JP4011172B2 - Three-dimensional drawing creation method from sheet metal CAD drawing and storage medium storing program thereof - Google Patents

Description

（１）初めに最小閉領域の投影を行う。まず、最小閉領域と縁線分を照合して仮の立体面を作成する際、最小閉領域と縁線分との対応検査を行う。この検査が終って初めて仮の面が作成でき、この仮の面は最終立体図形の一部分の候補となる。
【００８３】
まず、縁線分の端点における面切断フラグを調べる。もし面切断フラグがたっていたならば、その位置で最小閉領域を切断する。これを例を用いて説明する。仮に正面図の最小閉領域を側面図の縁線分と照合させることを考える。例えば、図１２の場合、側面図の縁線分ａの端点の位置により、正面図の最小閉領域Ａが切断されている。縁線分ａのもう一方の端点には面切断フラグが立っていないので切断は行わない。
【００８４】
次に、最小閉領域を切断した後、切断された最小閉領域と縁線分が対応するかどうかを、それらの位置によって検査する。図１３のように、切断された最小閉領域のＹ座標値の最大値、最小値をそれぞれＹ_RMAXとＹ_RMINとし、縁線分のＹ座標値の最大値、最小値をそれぞれＹ_FMAX、Ｙ_FMINとすると、以下が成り立つとき、最小閉領域と縁線分は対応するものとする。
【００８５】
Ｙ_ＲＭＡＸ＜Ｙ_ＦＭＡＸ＋（Ｙ_ＦＭＡＸ−Ｙ_ＦＭＩＮ）・α
Ｙ_ＲＭＩＮ＞Ｙ_ＦＭＩＮ−（Ｙ_ＦＭＡＸ−Ｙ_ＦＭＩＮ）・α
（ただしαは定数であり、本実施例では０．１とする）
【００８６】
（２）次に合成縁の掃引を行う。（１）で検査され、条件が満たされた場合、縁線分を適切な方向に掃引して仮の面を作る基になる面を作成する。縁線分の掃引方向は、図４で示した座標系にしたがって、図１４に示すように、正面図の縁線分はＺ軸方向、側面図の縁線分はＸ軸方向、平面図の縁線分はＹ軸方向とする。この掃引の結果、直線の縁線分を掃引した場合は平面ができ、円弧の縁線分を掃引した場合は円筒面ができる。図１４の例で説明すると、縁線分ａは側面図の縁線分であるから、図１５に示すように、Ｘ軸方向に掃引して面を作成する。
【００８７】
（３）次に、掃引面への投影を行う。
（２）で得られた掃引面に、図１６に示すように最小閉領域を投影する。この投影を施すことによって、最終結果の立体面の候補となる仮の立体面ができる。つまり結果の立体の一部分の候補である。
【００８８】
そして、仮の面の有効性の確認を行う。表１で示したように、上記の最小閉領域の投影処理で生成された仮の面の種類によって二種類の有効性の確認方法を取る。
【００８９】
（１）垂直、水平面（法線ベクトルがＸ、Ｙ、Ｚ軸のどれかと平行な面）の場合の確認。
この場合、仮の面の有効性の確認は、図１７に示すように、最後の矢視において適切な縁線分を見つけることによって行われる。例として正面図の最小閉領域を側面図の縁線分と照合し、平面図の矢視で仮の面の有効性を確かめるとする。この場合、縁線分がＹ軸と平行であるとすると仮の面はＸＹ平面に平行である。この仮の面のＺ座標をＺ_p とし、Ｘ座標の最大値をＸ_pmax、最小値をＸ_pminとする。この面が有効であるか確かめるために、まず平面図で、Ｘ軸と平行でＺ座標がＺ_p 付近である縁線分を探す。見つかった縁線分のＸ座標の最大値をＸ_fmax、最小値をＸ_fminとする。
【００９０】
このとき、以下の条件が満たされる場合は仮の面は有効であるとする。
縁線分の端点でＸ座標がＸ_ｐｍａｘであるものについて、
・面切断フラグが立っている場合：
【数２】
Ｘ_ｆｍａｘ＋（１＋α）・（Ｘ_ｐｍａｘ−Ｘ_ｐｍｉｎ）
＞Ｘ_ｐｍａｘ （αは定数）
・面切断フラグが立っていない場合：
Ｘ_ｆｍａｘ＞Ｘ_ｐｍａｘ
縁線分の端点でＹ座標がＸ_ｐｍｉｎであるものについて、
・面切断フラグが立っている場合：
Ｘ_ｆｍｉｎ＋（１−α）・（Ｘ_ｐｍａｘ−Ｘ_ｐｍｉｎ）
＜Ｘ_ｐｍｉｎ （αは定数。４−６−２節と同じ）
・面切断フラグが立っていない場合：
Ｘ_ｆｍｉｎ＜Ｘ_ｐｍｉｎ
（２）仮の面、および円筒面の場合
この場合、仮の面の有効性の認識は、図１８に示すように、仮の面を最後の矢視が表す平面（正面図なら平面、側面図ならばＹＺ平面、平面図ならばＺＸ平面）に投影し、そのシルエットとその矢視の最大外ループを比較することによって行われる。具体的には、シルエットが最大外ループの内部にあればその面は有効であるとする。
【００９１】
例として正面図の最小閉領域を側面図の縁線分と照合し、矢視で仮の面の有効性を確かめるとする。側面図の縁線分が円弧である場合、は円筒面になる。この円筒面を平面図の矢視（ＸＺ平面）に投影する。またここで、平面図の最大外ループを、最大外ループの頂点の平面位置を中心にしてαだけ拡大しておく。これは、あいまいさをある程度吸収する上で必要である。図１９に示すように、仮の面を投影したシルエットを拡大した最大外ループの内部にあるならば、仮の面は有効であるとする。
【００９２】
次に、虚物体排除処理部７は、穴の部分及び虚物体を排除する（Ｓ５）。以上の方法で構築された立体図形には、図２０の（ａ）に示すように、穴の形をした面および虚物体も含まれている場合が多い。そこで、立体図形と三面図を照合させることにより、これらを排除する。この穴を排除するためのアルゴリズムを以下に述べる。ただし、本説明では、図２０の（ｂ）に示すように、三面図において孤立ループによって表現される、法線ベクトルがＸ、Ｙ、Ｚ軸のいずれかと垂直な面に開いた穴にのみ対応しているとする。
【００９３】
１．内部の最小閉領域から立体面を作るとき、図２１の（ａ）に示すように、その最小閉領域をもとにした立体面が１枚しか生成されなければ、その面は穴を表す虚物体であるとして排除する。
【００９４】
２．また、図２１の（ｂ）に示すように、立体面が複数作られた場合、各面の照合に使われた合成縁線分を調べる。
【００９５】
例えば、立体面の座標の最大値および最小値と合成縁線分のもとになった単体縁線分の端点を比較することにより、その立体面が排除すべきかどうか判断する。
【００９６】
例として、図２２に示す正面図の最小閉領域Ａと、側面図、平面図の縁線分を合わせて面を生成した場合について説明する。立体面のＸ座標の最大値をＸ_ＭＡＸ 、最小値を Ｘ_ＭＩＮ 、Ｙ座標の最大値をＹ_ＭＡＸ 、最小値をＹ_ＭＩＮ とする。
【００９７】
ここで側面の合成縁線分について、それのもととなった単体縁線分の中で、端点のＹ座標がＹ_MAX およびＹ_MIN のものがあるかどうか調べる。また、平面の合成縁線分について、それのもととなった単体縁線分の中で、端点のＸ座標がＸ_MAX およびＸ_MIN のものがあるかどうか調べる。すべての場合（４種類）において適切な単体縁線分の端点が見つかれば、この立体面は穴を表す虚物体であるとして排除する。
【００９８】
すなわち、図２３に示すように、最小領域Ａからできた仮の面Ａａを３次元座標系のＹ−Ｚ面に定義し、この仮の面Ａａの座標と合成縁成分に含まれている単体縁成分の端点とを比較して排除する。
【００９９】
次に、立体図生成処理部８は、平面又は円筒面を組み合わせて立体図を作成する（Ｓ６）。
【０１００】
この立体図の生成は、ＣＡＤ上に立体面の集合で表現された立体図形を生成するが、この後にこれらの図形を利用する場合、ソリッド化をした方が望ましい場合もある。本例では、立体面の集合で表現した立体図形を生成しているので、ソリッド化は比較的容易である。もしソリッド化を行うならば、図２４に示すように、これらの立体面に板厚の厚みをつけて、ブーリアン演算のＯＲを実行すればよい。本例では生成した立体面の間には、立体面に板厚の厚みを与えることを考慮して、あらかじめ隙間を空けてある。すなわち、図２５に示すように、板金の３面ＣＡＤ図面から自動的に立体図が生成されることになる。
【０１０１】
従って、頂点と稜線の照合による手法では、頂点と稜線による手法では各矢視の頂点と稜線の座標がわずかにずれていたり、稜線が省略してあったりする場合、図面が簡単な場合でも立体図形の元となるワイヤーフレームモデルが正確に構築できず、その結果立体図形が生成できなかったが、本実施の形態ではトップダウン的手法により、面と線の照合によって立体図を生成するので、あいまいさをある程度吸収して立体を作成することができてる。
【０１０２】
なお、上記実施の形態では、板厚算出処理部４が板厚を自動的に求めるとしたがオペレータにより、予め板厚を入力させる場合は、その板厚を直接、縁線分生成処理部５に設定するようにしてもよい。
【０１０３】
【発明の効果】
以上のように、本発明によれば、図面の頂点と稜線の照合による立体作成では図面の持つあいまいさを克服するのは難しく、実際の図面への適用は困難であったが、トップダウン的一手法で各矢視の最小閉領域と縁線分の照合による立体図形生成手法−面領域照合法によって立体図を生成する。
【０１０４】
このため、
（１）板金図面から面単位の照合を行い、自動で立体図形を作成できた。
（２）多少の矢視間の位置の誤差を補って立体図形を作成できた。
（３）多少の図面の省略、データ不足を補って立体図形を作成できた。
（４）照合の単位を頂点と稜線から面単位にすることの有効性を確認できた。
【０１０５】
また、ボトムアップ的アプローチは頂点と稜線の照合により、ワイヤーフレームモデルを作成するが面領域照合法では、最小閉領域と縁線分を照合して立体図形を作成するので、それぞれの探索上の計算量を概算すると、明らかに計算量が少なくなる。
【０１０６】
さらに、ボトムアップ的アプローチでは、照合の結果ワイヤーフレームモデルを作成し、その後に面を生成してソリッドモデルとする。この場合、もしワイヤーフレームモデルが不完全だったならば、結果の物体は生成されない。つまり、図面に少しでも間違いがあると、結果の物体がまったく生成されなくなる。これに対し面領域照合法ではトップダウン的アプローチとして、先に面の存在を仮定してからそれを削除しながら最終立体を探索するアルゴリズムであり、面を削除する方法も完全に削除すべき理由がない限り削除しない。
【０１０７】
このため、結果として立体面が生成される可能性が高くなり、もし図面にボトムアップ的アプローチでは致命的な間違いが存在しても、面領域照合法の場合は図面が表す立体図形の一部分だけでも出力することが可能となる。
【図面の簡単な説明】
【図１】本発明の実施の形態の概略を説明する説明図である。
【図２】本発明のＣＡＤ板金三面図データから立体図を生成する方法の概略構成図である。
【図３】本実施の形態のＣＡＤ板金三面図データから立体図を生成する概略フローチャートである。
【図４】三面図の各矢視図の座標系を説明する説明図である。
【図５】最大外ループと最小閉領域のループを説明する説明図である。
【図６】図面誤りの検出を説明する説明図である。
【図７】平行線成分から板厚を求める手順を説明する説明図である。
【図８】縁線分の生成の手順を説明する説明図である。
【図９】円弧が存在する板金の縁線分の生成の手順を説明する説明図である。
【図１０】下板に円弧が存在する場合の面切断フラグの適用を説明する説明図である。
【図１１】照合の概略を説明する説明図である。
【図１２】最小閉領域の切断と照合とを説明する説明図である。
【図１３】座標系における照合条件を説明する説明図である。
【図１４】照合における３軸上の縁線成分の掃引を説明する説明図である。
【図１５】掃引による面の生成を説明する説明図である。
【図１６】最小領域の投影を説明する説明図である。
【図１７】面の有効性を説明する説明図である。
【図１８】平面図の投影を説明する説明図である。
【図１９】仮の面の有効性の確認の手法を説明する説明図である。
【図２０】虚物体を含む場合を説明する説明図である。
【図２１】生成された立体図に垂直面、水平面の穴ができる例を説明する説明図である。
【図２２】穴を表す面を削除する手順を説明する説明図である。
【図２３】平面に穴を定義する手法を説明する説明図である。
【図２４】本実施の形態によって生成された立体図を説明する説明図である。
【図２５】本実施の形態の手法によって生成される立体図の例を示す図である。
【図２６】従来の三面図の照合を説明する説明図である。
【図２７】従来における自動掃引法を説明する説明図である。
【図２８】従来の三面図の照合によって生成される虚像を説明する説明図である。
【図２９】従来における立体作成できない図面例を示す図である。
【符号の説明】
１ 矢視図読込処理部
３ 閉領域抽出処理部
４ 板厚算出処理部
５ 縁線分生成処理部
６ 照合処理部
７ 虚物体排除処理部
８ 立体図生成処理部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for creating a three-dimensional view from a sheet metal CAD drawing and a storage medium storing a program for creating a three-dimensional view from the sheet metal CAD drawing.
[0002]
[Prior art]
For a long time, it has been necessary to transmit a three-dimensional shape at a processing or construction work site. However, there is only a two-dimensional medium such as paper as a conceptual three-dimensional shape transmitting means that has not yet been real.
[0003]
In other words, how well a three-dimensional shape is reduced (represented) to two dimensions has been related to the efficiency of three-dimensional shape transmission. One of well-known methods for such efficient degeneration (expression) is a projection method.
[0004]
This method of expressing a three-dimensional shape by using a plurality of projection views has been applied to drawings and has played an important role industrially as an information transmission means for design and production for a long time. These pieces of drawing information are further expanded in terms of information processing as they are replaced with electronic data along with the spread of CAD.
[0005]
On the other hand, the method of logically expressing the three-dimensional shape inside the computer has made tremendous progress over the past 30 years, and the three-dimensional CAD called the three-dimensional shape can be visualized and applied. The practical value has also increased dramatically.
[0006]
Here, considering the significance of creating a three-dimensional shape from a drawing, there are the following two.
[0007]
The first is to help understand the three-dimensional shape shown in the drawing. Regardless of how efficient the projection method is, the three-dimensional shape is represented in two dimensions, so information such as bending lines is missing, and information is diffused over a plurality of projection views. For this reason, the more complicated the drawing becomes, the more difficult it is for those who are not familiar with the drawing to understand the three-dimensional shape represented by the drawing.
[0008]
Second, if a 3D shape can be created from 2D information, that is, a drawing, it can be connected to 3D technology without denying the industrial system and its assets established in the past.
[0009]
There are various methods for generating a three-dimensional solid shape from this two-dimensional information, but it can be roughly divided into a bottom-up approach and a top-down approach.
[0010]
<Bottom-up approach>
The basic concept of this bottom-up approach is to automatically create a solid by inputting each vertex coordinate and edge line based on a mathematically correct drawing (geometrical figure) as a projection drawing.
[0011]
In other words, it does not require a Boolean operation or local shape change peculiar to 3D shape modeling. Basically, vertices and ridgelines such as a front view, a side view, and a plan view of a projection drawing are collated with each other to construct a solid. For this reason, only the mathematically correct projection position is required for each input projection view, and other conditions such as phase and the like are not required.
[0012]
In this method, as shown in FIG. 26, a plurality of arrow projections in the drawing are first collated to create a wire frame composed of vertices and ridge lines in space. Two adjacent ridgelines are taken out from the created wire frame, and the type of the aspect including the two ridgelines is determined from the combination. The type of the situation can be determined from a combination of two ridge lines or a positional relationship. Thereafter, the other ridge lines on the curved surface are extracted and sequentially looped, and the specific shape of the curved surface is determined from the looped ridge lines.
[0013]
The advantage of this bottom-up approach is that there are no restrictions on the solid figure represented by the drawing to be applied, and that no operator operation is required during the creation of the solid.
[0014]
<Top-down approach>
The basic concept of the top-down approach is to consider a simple closed area for each arrow projection, and create a plurality of basic solids by matching related figures in a pattern between each arrow view.
[0015]
Further, the final solid is completed as an assembly of basic solids while observing the inclusion relation and connection state of these basic solids. This method uses concepts such as surfaces and loops at the stage of a projected view, and further performs processing such as Boolean operations in the course of progress.
[0016]
In the bottom-up approach described above, a wireframe is created by matching vertices and ridges, and then a surface is generated. On the other hand, in this method, it is assumed that a surface or a basic solid exists from the beginning, and that assumption is made. The feature is to search for the resulting solid based on the above. Here, the top-down includes not only forming a basic figure with a set of appropriate vertices and ridges as a closed region, but also an operator intervening in judgment as necessary.
[0017]
In the automatic sweep method which is one of the top-down methods, as shown in FIG. 27, a stepped solid or perforated plate can be created by giving an arbitrary thickness to each of a plurality of closed regions in the drawing.
[0018]
The first advantage of this top-down approach is the operator's intervention, etc., which can absorb some ambiguities, omissions, and subtle mistakes in the drawing, and search for candidate solids until the final solid is obtained. The space is narrow.
[0019]
The second is that the bottom-up approach is based on matching between vertices and edges, whereas this method is based on face-based matching.
[0020]
[Problems to be solved by the invention]
However, there are two main problems with the bottom-up approach. One is an increase in the amount of calculation for the purpose of eliminating virtual objects.
[0021]
In the method of first making a wire frame by collating vertices and ridge lines as in the bottom-up approach, as shown in FIG. 28, imaginary vertices, ridge lines, and surfaces that do not actually exist are created.
[0022]
In order to finally create a correct solid, it is necessary to eliminate these imaginary objects by phase relation, collation with the original projection map, and the like.
[0023]
In some cases, there is a possibility that an explosion of a combination may occur or a phase cannot be determined and a solid cannot be created.
[0024]
Another problem is finding a correct projection as an input to this approach. If there are ambiguous parts in the drawing, as shown in FIG. 29, the vertices and ridgelines of each arrow are slightly shifted so that they are not visible to humans, or the ridgeline at the point A is omitted. There is a problem that the wire frame in the middle of the verification is not correctly generated, and as a result, a three-dimensional figure is not created.
[0025]
In any case, the bottom-up approach determines the overall phase related to the formation of a solid at the end of a series of operations, so if one of a large number of planes is not created, it will eventually end up after a long calculation time. There may be no solution at all.
[0026]
In particular, when the CAD drawing vertex and ridge data are slightly shifted, many of them cannot create solids, but since the drawings themselves are correctly viewed by human eyes, the reason why they cannot be created cannot be found, and this is a big problem in practice. It becomes an obstacle.
[0027]
On the other hand, in the top-down approach, the operator gives information to the system at the time of creating a solid and creates the solid, so the operator must understand the drawing, so if you are not an experienced operator, you can use the top-down approach method. There was no problem.
[0028]
For example, even in the automatic sweep method described in the basic concept, the operator must understand how much sweep length should be given to each closed region of the drawing.
[0029]
Another problem is that there is a limitation on the solid figure represented by the applicable drawing. For example, in the case of the automatic sweep method, the solid figure shown in the drawing must be such that it can be created by performing a Boolean operation after sweeping a certain arrow drawing to create a temporary solid.
[0030]
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a method capable of automatically generating a three-dimensional map from a two-dimensional development view without operator intervention.
[0031]
[Means for Solving the Problems]
  The method for creating a three-dimensional drawing from a sheet metal CAD drawing of the present invention is based on the two-dimensional triangle method.On the displayThree-sided view of the two-dimensional figure of the drawn sheet metal structureIn the arrow viewline segmentThroneThis is a method for generating a three-dimensional map based on mark information.
[0032]
Storing means in which an XY plane, a YZ plane, and an XZ plane of a three-dimensional (X, Y, Z) coordinate system are defined,
The computer is
  FIG.Side view, plan view, front viewThroneRead all the mark information,These are defined as the corresponding YZ plane, XZ plane, and XY plane.Arrow view reading process,
[0033]
  For each defined arrow view, after extracting the outermost loop of the arrow view around the predetermined direction as an outer loop, the loop is reversed from each line segment constituting the outer loop of the arrow view. Extract all loops that are traced around as inner loopsA closed region extraction process to perform,
[0034]
  For each arrow view, the distance between the parallel segments of the inner loop isSatisfies certain conditionsFor the first inner loop, the interval between the line segments is determined as the plate thickness of the sheet metal structure, and a line passing through the center of the first inner loop in the arrow view is calculated from the plate thickness. The edge line component is defined as any one of the YZ plane, the XZ plane, and the XY plane.Edge line componentGenerationProcessing steps;
[0035]
  The edge line component is swept in a direction perpendicular to the YZ plane, the XZ plane, or the XY plane where the edge line component is defined to generate respective sweep planes.,
  The first inner loop of the inner loops of the arrow view existing on the YZ plane, the XZ plane, or the XY plane opposed in the vertical direction to these sweep planes. A processing step of projecting the second inner loop to be removed onto the sweep surface to create and display the three-dimensional view;
The gist is to do.
[0036]
  A storage medium storing a program for creating a three-dimensional view from a sheet metal CAD drawing of the present invention is based on the two-dimensional triangle method.On the displayThree-sided view of the two-dimensional figure of the drawn sheet metal structureIn the arrow viewline segmentThroneIt is a storage medium that stores a program for generating a three-dimensional map based on mark information.
[0037]
Storing means in which an XY plane, a YZ plane, and an XZ plane of a three-dimensional (X, Y, Z) coordinate system are defined,
In the computer,
  FIG.Side view, plan view, front viewThroneRead all the mark information,These are defined as the corresponding YZ plane, XZ plane, and XY plane.Arrow view reading process,
  For each defined arrow view, after extracting the outermost loop of the arrow view around the predetermined direction as an outer loop, the loop is reversed from each line segment constituting the outer loop of the arrow view. Extract all loops that are traced around as inner loopsA closed region extraction process to perform,
  For each arrow view, the distance between the parallel segments of the inner loop isSatisfies certain conditionsFor the first inner loop, the interval between the line segments is determined as the plate thickness of the sheet metal structure, and a line passing through the center of the first inner loop in the arrow view is calculated from the plate thickness. The edge line component is defined as any one of the YZ plane, the XZ plane, and the XY plane.Edge line componentGenerationProcessing steps;
  The edge line component is swept in a direction perpendicular to the YZ plane, the XZ plane, or the XY plane where the edge line component is defined to generate respective sweep planes.,
  The first inner loop of the inner loops of the arrow view existing on the YZ plane, the XZ plane, or the XY plane opposed in the vertical direction to these sweep planes. A processing step of projecting the second inner loop to be removed onto the sweep surface to create and display the three-dimensional view;
ExecuteThis is the gist.
[0038]
This facilitates the installation and execution of this program and improves the distribution.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
As explained in the above problem, the bottom-up approach cannot absorb the ambiguity, omission, some errors and accuracy problems of the drawing. However, creating a three-dimensional shape from a drawing is not so easy.
[0040]
In the three-dimensional CAD, the shape input method is significantly different from that of the conventional two-dimensional CAD drafting, and complicated and three-dimensional thinking is required. Therefore, the burden on the operator is extremely increased.
[0041]
For this reason, if a system for automatically creating a three-dimensional object from a drawing can be achieved, the above two meanings can be satisfied and the burden on the operator can be significantly reduced.
[0042]
What are the features of the drawings that can be handled by such a system? First, there is a lack of information and diffusion as described above, but it also includes many conventions, implicit understandings, and small and large mistakes (including accuracy issues). Humans understand these drawings by interpreting them each time to correct or correct information, but it is very difficult for computers to do it. For this reason, technology that automatically creates solids from drawings written by humans is strongly desired in the industry, but there are no examples of practical application. .
[0043]
(1) Human-drawn drawings are not completely accurate and include ambiguous expressions, mistakes, and omissions. How do we make a robust system that absorbs those expressions, and what is its core algorithm?
[0044]
(2) The shape and accuracy displayed in the drawing must correspond to the shape and accuracy of the completed solid and the shape and accuracy of the completed solid. That is, if the expected 3D shape is different from the completed 3D shape, the cause must be an algorithm that can be easily recognized on the drawing. It's a problem if a nearly complete drawing is not created by a single mistake.
Is given.
[0045]
The bottom-up approach that has been generally used so far (creating solid figures by matching the vertices and ridges between the arrow views) requires a complete drawing as a premise and makes it ambiguous drawing written by humans. Is difficult to apply.
[0046]
Therefore, the present invention uses a top-down approach system that can handle ambiguous expressions that are not problematic as projection drawings but are not problematic as practical drawings.
[0047]
In this method, not the verification of the vertices and the edge lines, but the verification of the graphic that is a larger unit is performed. That is, some errors are absorbed by global collation in units of areas. Therefore, an actual drawing can be handled without any problem, but the shape of the region in the thickness direction is not guaranteed. However, it is important for sheet metal with a constant thickness. Therefore, the object of the drawing to handle is limited to the three-sided view showing “sheet metal”.
[0048]
In addition, the solid figure represented in the drawing is
(3) A plane whose normal vector is perpendicular to any of the X, Y, and Z axes
(4) A cylindrical surface whose central axis is parallel to any of the X, Y, and Z axes
It must consist of In addition, the drawing as a three-dimensional projection diagram is a three-view diagram on the CAD of only a geometric shape constituted by straight lines and arcs.
[0049]
Furthermore, since the sheet metal has a constant thickness, the completed three-dimensional shape is expressed by a set of three-dimensional surfaces. By providing these assumptions, a solid is created from a drawing including some mistakes and omissions only by the judgment of the computer without operator intervention.
[0050]
An outline of a method for creating a solid from a three-view drawing only by the judgment of the computer will be described below.
[0051]
<Outline of the invention>
FIG. 1 is an explanatory diagram for explaining the outline of an embodiment of the present invention. Further, in the present embodiment, the top-down approach refers to creation of a solid based on the judgment of a computer without operator intervention. Moreover, it is set as the sheet metal three-sided view on CAD.
[0052]
In the present invention, as shown in FIG. 1, first, in the three views (front view, side view, plan view), the minimum closed regions (A, B, a, b, c, d) of the respective surfaces are extracted. The sheet thickness of the sheet metal is predicted based on the information. Then, using the obtained thickness value, an edge line segment representing the edge is extracted.
[0053]
After that, the minimum closed area represents the shape of the solid surface, and the edge line segment represents the position of the solid surface, and the minimum closed area and the edge line segment are collated (called surface area collation) to create a solid surface. To do.
[0054]
That is, the present invention is a three-dimensional drawing creation method limited to “bending and cutting” of a sheet metal having a constant thickness.
[0055]
On the other hand, the features of the sheet metal drawing in which the processing method is limited as described above can be described as follows.
[0056]
・ Since the plate thickness is constant, the closed loop of line segments (hereinafter referred to as the closed region) appearing in the geometric figure of the drawing is basically a three-dimensional surface (including a hole as an imaginary plane) and its side surface ( Hereinafter, this is referred to as “edge”), and the overlapping of these closed regions is shown.
[0057]
-The surface represents the shape of a solid surface, and the edges represent the position and orientation of the surface.
-Since the original is a single plate, the shape of the solid figure is limited.
Based on such characteristics, the following restrictions are added.
(I). The drawing must consist of straight lines and arcs.
(B). The solid figure represented by the drawing is composed of a plane whose normal vector is perpendicular to any of the X, Y and Z axes and a cylindrical surface whose central axis is parallel to any of the X, Y and Z axes.
[0058]
With the above, the sheet metal diagramFaceThe shape is quite limited, making it easier to capture the shape of a solid figure. However, because of the drawings as described above, there are many ambiguous points. For example, since the plate thickness is constant, the plate thickness can be accurately written or the side surfaces of the holes can be omitted. In these cases, the conventional bottom-up approach could hardly produce solids.
[0059]
Hereinafter, a method for creating a three-dimensional view from a three-dimensional view of a CAD sheet metal will be described with reference to the block diagram of FIG.
[0060]
As shown in FIG. 2, the method according to the present embodiment includes an arrow view reading processing unit 1 that reads two-dimensional CAD sheet metal three-view drawing data for each surface and stores it in the memory 2, and an arrow view reading process. After the section 1 reads each arrow view data, the closed area extraction processing section 3 that extracts the closed area from each arrow view data in the memory 2 is compared with the extracted closed areas to determine the thickness of the drawing. A plate thickness calculation processing unit 4 to be obtained and an edge line segment generation processing unit 5 that converts a closed region corresponding to the plate thickness into an edge component (line) in accordance with the calculation of the plate thickness are provided.
[0061]
In addition, the minimum closed area and the edge line component to be a surface are defined in a coordinate system corresponding to the arrow view, and the edge line component and the minimum closed area of each coordinate system are swept in a predetermined direction. A collation processing unit 6 that creates a surface and collates whether or not an edge component exists in a direction perpendicular to the surface to generate a part of the solid, and the collation processing unit 6 makes the part of the solid diagram Compare the surface with the surface on the coordinate system corresponding to the surface, andThe same thingIf there is a body (imaginary object), the imaginary object is excluded from each surface of the three-dimensional diagram generated by the imaginary object exclusion processing unit 7 that excludes the object from the surface that is a part of the three-dimensional diagram and the matching processing unit 6 Then, a three-dimensional map generation processing unit 8 that combines a part of the surfaces of the three-dimensional map and outputs them to a display unit (not shown) or a printing unit (not shown) is provided.
[0062]
A method for creating a three-dimensional view from the CAD sheet metal three-view drawing configured as described above will be described with reference to the flowchart of FIG.
[0063]
First, a minimum closed region is extracted from each arrow data (front view, side view, plan view) of the CAD sheet metal three-view drawing (S1). This region is extracted by extracting an isolated line segment (a line segment in which any one of the end points is not connected to any other line segment) and removing it if possible. In order to facilitate the extraction of the minimum closed region, vertices are generated as data in the CAD at the intersections of the intersected line segments.
[0064]
That is, the arrow view reading processing unit 1 shown in FIG. 2 determines a coordinate system for each surface (front view, side view, plan view) of the two-dimensional sheet metal three-view drawing as shown in FIG. (In the case of the third trigonometric method)
[0065]
Then, the closed region extraction processing unit 3 extracts the minimum closed region from each arrow drawing as shown in FIG. First, as shown in FIG. 5A, the outermost vertex Ai in a certain arrow view is searched. A loop is taken clockwise from the vertex Ai so as to trace the outline of the drawing. This loop is referred to as the “maximum outer loop” as viewed in this arrow. Next, as shown in FIG. 5B, the loop is then taken counterclockwise from each line segment followed by the maximum outer loop. This maximumOutsideThese loops obtained by looping counterclockwise from the loop are defined as the minimum closed region.
[0066]
Also, there is no trace from the line segment that the maximum outer loop followed. Therefore, as shown in FIG. 5 (c), if there is a loop independent from other loops, find the one containing the loop in the minimum closed region obtained so far. to add. Further, as shown in FIG. 6, if these loops (maximum outer loop, minimum closed region) cannot be created, the user is informed that the drawing is wrong.
[0067]
Next, the sheet thickness calculation processing unit 4 predicts the sheet thickness of the sheet metal represented by the drawing based on the extracted data of the minimum closed region (S2). In the calculation of the plate thickness, each line segment constituting the minimum closed region is referred to as “side”.
[0068]
As shown in FIG. 7A, the plate thickness calculation processing unit 4 extracts pairs of parallel line segments from the minimum closed regions of all the arrows obtained by the closed region extraction processing unit 3. For example, for each side of the minimum closed region, a corresponding side that is a straight line for a straight side and an arc for a side of an arc is found and set as a pair of sides. At this time, as shown in FIG. 7B, the corresponding sides are searched under the condition that the sides are opposed to each other.
[0069]
For the pair of sides thus obtained, the average of the lengths of the two sides is expressed as L as shown in FIG._i, The distance between sides is T_iAnd Here is the value T_tAnd
[Expression 1]
T_t・ (1-dt) <T_i<T_t(1 + dt) (dt: constant)
L for all i such that_iFind the sum of L_tAnd L obtained in this way_tL is the largest of_tmaxThen
L_t<L_tmax・ C (C is a constant close to 1)ExampleThen, for convenience 0.7)
L that satisfies_tOut of T_tIs the smallest T_tIs the plate thickness. This thickness is hereinafter referred to as t.
[0070]
Based on the thickness t, the edge line component creation processing unit 5 extracts a line segment representing an edge from the minimum closed region obtained in step S1 (hereinafter, this line segment is referred to as an edge line segment) (S3). .
[0071]
For example, the obtained plate thickness t is applied to a pair of parallel sides of each minimum closed region in FIG. The distance between the sides of a pair is T_iThen, for the plate thickness t, t · (1-dt) <T_i<t(1+dt) (dt: constant used in FIG. 7C), a line segment passing between the two sides as shown in FIG. And make it a single edge segment. This is performed for a pair of sides obtained from the minimum closed region of all arrows. In this manner, straight line and arc edge segments are extracted.
[0072]
Next, the edge line component generation processing unit 5 synthesizes a single edge line segment. For example, as shown in FIG. 8B, the single edge line segment obtained by the plate thickness calculation processing unit 4 is a single edge line segment of a plurality of straight lines that are on the same line and are adjacent to each other. Is synthesized.
[0073]
There are also two simple edgesline segmentAre adjacent to each other with a gap of about the plate thickness, these edge line segments are combined into one combined edge line segment. Hereinafter, the term “edge line segment” refers to a combined edge line unless otherwise specified. The single edge of the arc is not combined.
[0074]
Next, the edge line component generation processing unit 5 determines a face cutting flag. The determination of the chamfer cutting flag is performed in the case of a three-dimensional figure as shown in FIG. 9A in which the plane and the cylindrical surface are smoothly connected (in general, when the curved surfaces are smoothly connected), Do not draw a border between the faces. However, if this boundary line is not drawn correctly, as described above, it is not possible to generate a three-dimensional view from the three views of the sheet metal.
[0075]
Therefore, it is possible to simultaneously generate the three-dimensional plane and the cylindrical surface by collating the minimum closed region (A in FIG. 9A) representing the plane and the cylindrical surface with the other straight line and the edge of the arc. Without generating the plane and the cylindrical surface separately. By creating a three-dimensional surface in this way, consistency in the algorithm is maintained.
[0076]
At this time, in A of FIG. 9A, the maximum length is larger than the corresponding straight line and the edge of the arc corresponding to the other arrows. Therefore, by defining a face cutting flag at each end point of the edge line segment, as shown in FIG. 9B, the minimum closed area is cut to the size of the edge line segment, and the size is set appropriately. Perform verification.
[0077]
Specifically, the face cutting flag is set when each end point of the edge line segment is in the following state.
・ When the edge line is an arc
・ When the edge line is a straight line and smoothly connects to the edge of the arc at the end point
However, as a disadvantage of this method, as shown in FIG. 10, since the cutting flag is applied even to the minimum closed region that does not represent the cylindrical surface, an unnecessary surface may be formed.
[0078]
Next, the matching processing unit 6 determines the minimum region of each arrow obtained in step S1 as the edge line of the other arrow.MinA surface (also referred to as a temporary surface) of the three-dimensional map projected on the surface that has been swept is created (S4).
[0079]
This collation process collates the minimum closed region obtained in step S1 and the edge line segment obtained in step S3 to create a three-dimensional figure. However, the normal vector is a plane perpendicular to any of the X, Y, and Z axes, and the central axis is a cylindrical surface parallel to any of the X, Y, and Z axes.
[0080]
In any case, as shown in FIG. 11, first, a three-dimensional surface is created by checking the minimum closed region of the arrow on the drawing with the corresponding edge line of any other arrow. The collation method of confirming the effectiveness of the three-dimensional surface by using the data of the arrows.
[0081]
Further, the processing method is changed depending on the type of the three-dimensional surface formed by collating the first arrow and the edge line segment. For example, the validity of a surface whose normal vector is parallel to any of the X, Y, and Z axes is confirmed by the edge segment of the last arrow. The validity of the plane whose normal vector is not parallel to any of the X, Y, and Z axes (hereinafter referred to as an oblique surface) and the cylindrical surface is confirmed by the maximum outer loop of the last arrow view. Therefore, a possible collation method is as shown in Table 1. The details of the verification processing procedure will be described below.
[0082]
[Table 1]

(1) First, the projection of the minimum closed region is performed. First, when creating a temporary solid surface by collating the minimum closed region and the edge line segment, a correspondence inspection between the minimum closed region and the edge line segment is performed. Only after this inspection is completed, a temporary surface can be created, and this temporary surface becomes a candidate for a part of the final solid figure.
[0083]
First, the surface cutting flag at the end point of the edge line segment is examined. If the face cutting flag is on, the minimum closed area is cut at that position. This will be described using an example. Suppose that the minimum closed region of the front view is collated with the edge line segment of the side view. For example, in the case of FIG. 12, the minimum closed region A in the front view is cut by the position of the end point of the edge line segment a in the side view. Since the face cutting flag is not set at the other end point of the edge line segment a, cutting is not performed.
[0084]
Next, after cutting the minimum closed region, whether or not the cut minimum closed region corresponds to the edge line segment is inspected by their positions. As shown in FIG. 13, the maximum value and the minimum value of the Y coordinate value of the cut minimum closed region are set to Y, respectively._RMAXAnd Y_RMINThe maximum and minimum Y coordinate values of the edge line segment are Y_FMAX, Y_FMINThen, when the following holds, the minimum closed region corresponds to the edge line segment.
[0085]
Y_RMAX<Y_FMAX+ (Y_FMAX-Y_FMIN) ・ Α
Y_RMIN> Y_FMIN-(Y_FMAX-Y_FMIN) ・ Α
(Where α is a constant,In this example0.1)
[0086]
(2) Next, the composite edge is swept. If the condition is satisfied when inspected in (1), the edge line segment is swept in an appropriate direction to create a surface that forms a temporary surface. As shown in FIG. 14, the sweep direction of the edge line segment is in the Z-axis direction, the edge line segment in the side view is in the X-axis direction, and the plan view is in accordance with the coordinate system shown in FIG. The edge line segment is the Y-axis direction. As a result of this sweep, a plane is formed when a straight edge line is swept, and a cylindrical surface is formed when an arc edge line is swept. In the example of FIG. 14, the edge line segment a is an edge line segment of the side view, and thus a surface is created by sweeping in the X-axis direction as shown in FIG. 15.
[0087]
(3) Next, projection onto the sweep surface is performed.
A minimum closed region is projected onto the sweep surface obtained in (2) as shown in FIG. By performing this projection, a temporary solid surface that is a candidate for the final solid surface is created. That is, it is a candidate for a part of the resulting solid.
[0088]
Then, the effectiveness of the temporary surface is confirmed. As shown in Table 1, the above minimumCloseTwo types of validity confirmation methods are taken depending on the type of the provisional surface generated by the region projection processing.
[0089]
(1) Confirmation in the case of a vertical or horizontal plane (a normal vector is a plane parallel to any of the X, Y, and Z axes).
In this case, the validity of the temporary surface is confirmed by finding an appropriate edge line segment in the last arrow view, as shown in FIG. As an example, the minimum closed area of the front view is checked against the edge line segment of the side view, and the validity of the temporary surface is confirmed by the arrow view of the plan view. In this case, if the edge line segment is parallel to the Y axis, the temporary surface is parallel to the XY plane. The Z coordinate of this temporary surface is Z_pAnd the maximum value of the X coordinate is X_pmax, The minimum value is X_pminAnd To see if this surface is valid, first in a plan view, the Z coordinate parallel to the X axis is Z_pLook for edge lines that are nearby. The maximum value of the X coordinate of the found edge line segment is X_fmax, The minimum value is X_fminAnd
[0090]
At this time, it is assumed that the temporary surface is valid when the following conditions are satisfied.
The X coordinate at the end point of the edge line segment is X_pmaxAbout what is
・ When the face cutting flag is set:
[Expression 2]
X_fmax+ (1 + α) · (X_pmax-X_pmin)
> X_pmax      (Α is a constant)
・ If the face cutting flag is not set:
X_fmax> X_pmax
The Y coordinate is X at the end point of the edge line segment_pminAbout what is
・ When the face cutting flag is set:
X_fmin+ (1-α) · (X_pmax-X_pmin)
<X_pmin      (Α is a constant. Same as section 4-6-2)
・ If the face cutting flag is not set:
X_fmin<X_pmin
(2)For temporary and cylindrical surfaces
In this case, as shown in FIG. 18, the validity of the temporary surface is recognized by the plane represented by the last arrow (the plane is a front view, the YZ plane is a side view, and the ZX plane is a plan view). ) And comparing the silhouette and the maximum outer loop of the arrow view. Specifically, if the silhouette is inside the maximum outer loop, the surface is valid.
[0091]
As an example, the minimum closed area of the front view is checked against the edge line segment of the side view, and the validity of the temporary surface is confirmed by the arrow view. When the edge line segment of the side view is an arc, it becomes a cylindrical surface. This cylindrical surface is projected onto a plan view (XZ plane). Here, the maximum outer loop of the plan view is enlarged by α around the plane position of the vertex of the maximum outer loop. This is necessary to absorb some ambiguity. As shown in FIG. 19, it is assumed that the temporary surface is valid if it is inside the maximum outer loop obtained by enlarging the silhouette projected from the temporary surface.
[0092]
Next, the imaginary object exclusion processing unit 7 excludes the hole portion and the imaginary object (S5). In many cases, the three-dimensional figure constructed by the above method includes a hole-shaped surface and a virtual object as shown in FIG. Therefore, these are eliminated by collating the three-dimensional figure with the three views. An algorithm for eliminating this hole is described below. However, in this description, (bAs shown in FIG. 5, it is assumed that the normal vector represented by an isolated loop in the three-view diagram corresponds only to a hole opened in a plane perpendicular to any of the X, Y, and Z axes.
[0093]
1. When creating a solid surface from the internal minimum closed region, as shown in FIG. 21A, if only one solid surface based on the minimum closed region is generated, the surface is an imaginary representing a hole. Eliminate as an object.
[0094]
2. In addition, as shown in FIG. 21B, when a plurality of three-dimensional surfaces are created, the composite edge line segment used for collating each surface is examined.
[0095]
For example, it is determined whether or not the solid surface should be excluded by comparing the maximum value and minimum value of the coordinates of the solid surface with the end points of the single edge line that is the basis of the composite edge line segment.
[0096]
As an example, the minimum closed region of the front view shown in FIG.AAnd the case where a surface is produced | generated combining the edge line segment of a side view and a top view is demonstrated. The maximum value of the X coordinate of the solid surface is X_MAX, The minimum value X_MIN, The maximum Y coordinate value is Y_MAX, The minimum value is Y_MINAnd
[0097]
Here, for the combined edge line of the side surface, the Y coordinate of the end point is Y_MAXAnd Y_MINFind out if there are any. In addition, for the combined edge line of the plane, the X coordinate of the end point is X_MAXAnd X_MINFind out if there are any. If an end point of a suitable single edge line segment is found in all cases (four types), this solid surface is excluded as a virtual object representing a hole.
[0098]
That is, as shown in FIG. 23, a provisional surface Aa formed from the minimum area A is defined as a YZ plane of a three-dimensional coordinate system, and the coordinates of the provisional surface Aa and a single unit included in the combined edge component Eliminate by comparing with the edge of the edge component.
[0099]
Next, the three-dimensional view generation processing unit 8 creates a three-dimensional view by combining planes or cylindrical surfaces (S6).
[0100]
The three-dimensional diagram is generated by generating a three-dimensional figure represented by a set of three-dimensional planes on the CAD. However, when these figures are used thereafter, it may be desirable to solidify the figure. In this example, since a solid figure expressed by a set of solid surfaces is generated, solidification is relatively easy. If solidification is to be performed, as shown in FIG. 24, these three-dimensional surfaces are given thicknesses, and a Boolean operation OR is executed. In this example, a gap is created in advance between the generated solid surfaces in consideration of giving a thickness to the solid surfaces. That is, as shown in FIG. 25, a three-dimensional view is automatically generated from the three-surface CAD drawing of the sheet metal.
[0101]
Therefore, in the method using vertex and ridge line matching, the vertex and ridge line coordinates are slightly shifted in the arrow and ridge line method, or the ridge line is omitted. The wireframe model that is the basis of the figure could not be constructed correctly, and as a result a solid figure could not be generated, but in this embodiment, a three-dimensional view is generated by collating faces and lines with a top-down method, It is possible to create a solid by absorbing the ambiguity to some extent.
[0102]
In the above embodiment, the plate thickness calculation processing unit 4 automatically determines the plate thickness. However, if the operator inputs the plate thickness in advance, the plate thickness is directly set to the edge.lineThe minute generation processing unit 5 may be set.
[0103]
【The invention's effect】
As described above, according to the present invention, it is difficult to overcome the ambiguity of drawings in the creation of a solid by matching the vertices and ridges of the drawings, and it is difficult to apply to the actual drawings. A three-dimensional figure is generated by a three-dimensional figure generation method-surface area matching method by matching the minimum closed region and edge line segment of each arrow in one method.
[0104]
For this reason,
(1) A surface figure was collated from a sheet metal drawing, and a three-dimensional figure could be automatically created.
(2) A solid figure could be created by compensating for some positional error between arrows.
(3) A three-dimensional figure could be created by making up for some omission of drawings and lack of data.
(4) The effectiveness of changing the unit of collation from a vertex and a ridge to a surface unit was confirmed.
[0105]
In addition, the bottom-up approach creates a wireframe model by matching vertices and ridge lines, but the surface area matching method creates a 3D figure by matching the minimum closed area and the edge line segment. Estimating the amount of calculation clearly reduces the amount of calculation.
[0106]
Furthermore, in the bottom-up approach, a wireframe model is created as a result of collation, and then a surface is generated to form a solid model. In this case, if the wireframe model is incomplete, the resulting object is not generated. In other words, if there is any mistake in the drawing, the resulting object will not be generated at all. On the other hand, in the surface area matching method, as a top-down approach, it is an algorithm that searches for the final solid while first deleting the surface after assuming the presence of the surface. Do not delete unless there is.
[0107]
As a result, there is a high possibility that a solid surface will be generated, and even if there is a fatal mistake in the bottom-up approach in the drawing, only a part of the solid figure represented by the drawing in the case of the surface area matching method But it is possible to output.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining an outline of an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a method for generating a three-dimensional view from CAD sheet metal three-view data of the present invention.
FIG. 3 is a schematic flowchart for generating a three-dimensional view from CAD sheet metal three-view drawing data of the present embodiment.
FIG. 4 is an explanatory diagram for explaining a coordinate system of each arrow view of a three-view drawing.
FIG. 5 is an explanatory diagram for explaining a maximum outer loop and a minimum closed region loop;
FIG. 6 is an explanatory diagram illustrating detection of drawing errors.
FIG. 7 is an explanatory diagram for explaining a procedure for obtaining a plate thickness from parallel line components;
FIG. 8 is an explanatory diagram illustrating a procedure for generating edge line segments.
FIG. 9 is an explanatory diagram for explaining a procedure for generating an edge line segment of a sheet metal in which an arc exists.
FIG. 10 is an explanatory diagram for explaining application of a chamfering flag when a circular arc exists on the lower plate.
FIG. 11 is an explanatory diagram for explaining an outline of collation.
FIG. 12 is an explanatory diagram for explaining cutting and collation of a minimum closed region.
FIG. 13 is an explanatory diagram illustrating collation conditions in the coordinate system.
FIG. 14 is an explanatory diagram illustrating sweeping of edge line components on three axes in collation.
FIG. 15 is an explanatory diagram illustrating generation of a surface by sweeping.
FIG. 16 is an explanatory diagram illustrating projection of a minimum area.
FIG. 17 is an explanatory diagram for explaining the effectiveness of a surface.
FIG. 18 is an explanatory diagram for explaining projection of a plan view.
FIG. 19 is an explanatory diagram illustrating a method for confirming the effectiveness of a temporary surface.
FIG. 20 is an explanatory diagram illustrating a case where a virtual object is included.
FIG. 21 is perpendicular to the generated stereogram.surfaceIt is explanatory drawing explaining the example which can make the hole of a horizontal surface.
FIG. 22 is an explanatory diagram illustrating a procedure for deleting a surface representing a hole.
FIG. 23 is an explanatory diagram illustrating a technique for defining a hole in a plane.
FIG. 24 is an explanatory diagram illustrating a three-dimensional view generated according to the present embodiment.
FIG. 25 is a diagram illustrating an example of a three-dimensional view generated by the method of the present embodiment.
FIG. 26 is an explanatory diagram for explaining the matching of the conventional three views.
FIG. 27 is an explanatory diagram for explaining a conventional automatic sweep method.
FIG. 28 is an explanatory diagram for explaining a virtual image generated by collation of a conventional three-view diagram.
FIG. 29 is a diagram illustrating an example of a drawing in which a solid cannot be created in the related art.
[Explanation of symbols]
1 Arrow view reading processing section
3 Closed area extraction processing section
4 Thickness calculation processing section
5 Edge segment generation processing unit
6 Verification processing part
7 Virtual object exclusion processing part
8 3D map generation processing unit

Claims (10)

A method of producing a three-dimensional view based on line segments coordinate information arrow view in three orthographic views of the two-dimensional figure of the sheet metal structure depicted on the display unit based on 2-dimensional trigonometry,
A storage unit in which an XY plane, a YZ plane, and an XZ plane of a three-dimensional (X, Y, Z) coordinate system are defined ;
The computer is
Side view wherein an arrow view, a plan view, read all the coordinate information of the front view, the Y-Z plane of these relevant, the X-Z plane, arrow view read to define the X-Y plane Processing steps;
For each defined arrow view, after extracting the outermost loop of the arrow view around the predetermined direction as an outer loop, the loop is reversed from each line segment constituting the outer loop of the arrow view. A closed region extraction process that extracts all the loops traced around as inner loops ;
For each first view of the inner loop in which the distance between the parallel line segments of the inner loop satisfies a predetermined condition for each arrow view, the space between the line segments of the sheet metal structure Obtained as a plate thickness, a line passing through the center of the first inner loop of the arrow view from this plate thickness is defined as an edge line component representing an edge of the inner loop, and these edge line components are An edge line component generation processing step defined in any of the YZ plane, the XZ plane, and the XY plane ;
The edge line component is swept in a direction perpendicular to the YZ plane, the XZ plane, or the XY plane where the edge line component is defined to generate respective sweep planes. ,
The first inner loop of the inner loops of the arrow view existing on the YZ plane, the XZ plane, or the XY plane opposed in the vertical direction to these sweep planes. A method for creating a three-dimensional diagram from a sheet metal CAD drawing , wherein the second inner loop except for the processing step is performed by projecting the second inner loop onto the sweep surface to create and display the three-dimensional diagram. The processing step includes
The computer is
When the arrow view facing the sweep surface is parallel to the sweep surface, a step of generating a temporary solid surface by projecting the second inner loop of the parallel arrow view onto the sweep surface When,
Confirming the validity of the temporary solid surface by finding an appropriate edge line component corresponding to the temporary solid surface in the other arrow view defined on the non-projected surface; A method for creating a three-dimensional diagram from a sheet metal CAD drawing according to claim 1 wherein: The processing step includes
The computer
When the sweep surface facing the arrow view defined on the surface is an oblique surface or a cylinder that does not close, a temporary solid surface that projects the second inner loop of the arrow view onto the sweep surface Generating
Checking the effectiveness of the temporary solid surface by comparing the temporary solid surface with the outer loop of the other arrow view defined on the surface facing the temporary solid surface in the vertical direction;
The method for creating a three-dimensional diagram from a sheet metal CAD drawing according to claim 1, wherein: 4. The sheet metal CAD drawing according to claim 2 , wherein after the validity is confirmed, the sheet thickness is added to the temporary solid surface and the solid surface is displayed on the display unit. 5. 3D drawing creation method. The computer is
When the inner loop of the arrow view is extracted all the steps of each arrow FIG sequentially extracts the pair of parallel line segments in each loop,
And determined Mel step the vertical distance of the line segment parallel to each other,
Comparing each vertical distance of each inner loop, and setting the inner loop having the narrowest distance interval as the first inner loop ;
A method for creating a three-dimensional diagram from a sheet metal CAD drawing according to claim 1 , wherein a sheet thickness calculation processing step including : A storage medium storing a program for generating a three-dimensional view based on line segments coordinate information arrow view in three orthographic views of the two-dimensional figure of drawn sheet metal structure on the display unit based on 2-dimensional trigonometry ,
A storage unit in which an XY plane, a YZ plane, and an XZ plane of a three-dimensional (X, Y, Z) coordinate system are defined ;
In the computer,
Side view wherein an arrow view, a plan view, read all the coordinate information of the front view, the Y-Z plane of these relevant, the X-Z plane, arrow view read to define the X-Y plane Processing steps;
For each defined arrow view, after extracting the outermost loop of the arrow view around the predetermined direction as an outer loop, the loop is reversed from each line segment constituting the outer loop of the arrow view. A closed region extraction process that extracts all the loops traced around as inner loops ;
For each first view of the inner loop in which the distance between the parallel line segments of the inner loop satisfies a predetermined condition for each arrow view, the space between the line segments of the sheet metal structure Obtained as a plate thickness, a line passing through the center of the first inner loop of the arrow view from this plate thickness is defined as an edge line component representing an edge of the inner loop, and these edge line components are An edge line component generation processing step defined in any of the YZ plane, the XZ plane, and the XY plane ;
The edge line component is swept in a direction perpendicular to the YZ plane, the XZ plane, or the XY plane where the edge line component is defined to generate respective sweep planes. ,
The first inner loop of the inner loops of the arrow view existing on the YZ plane, the XZ plane, or the XY plane opposed in the vertical direction to these sweep planes. A program for creating a three-dimensional drawing from a sheet metal CAD drawing for executing the processing step of projecting the second inner loop except the projection onto the sweep surface and generating and displaying the three-dimensional drawing is stored. Storage medium. The processing step includes
In the computer,
When the arrow view facing the sweep surface is parallel to the sweep surface, a step of generating a temporary solid surface by projecting the second inner loop of the parallel arrow view onto the sweep surface When,
Confirming the validity of the temporary solid surface by finding an appropriate edge line component corresponding to the temporary solid surface in the other arrow view defined on the non-projected surface; A storage medium storing a program for creating a three-dimensional drawing from a sheet metal CAD drawing according to claim 6 for executing the following. The processing step includes
In the computer,
When the sweep surface facing the arrow view defined on the surface is an oblique surface or a cylinder that does not close, a temporary solid surface that projects the second inner loop of the arrow view onto the sweep surface Generating
Checking the effectiveness of the temporary solid surface by comparing the temporary solid surface with the outer loop of the other arrow view defined on the surface facing the temporary solid surface in the vertical direction;
The storage medium which memorize | stored the program which produces the solid figure from the sheet-metal CAD drawing of Claim 6 for performing this . The processing step includes
On the computer ,
9. After the validity is confirmed, a three-dimensional view is created from a sheet metal CAD drawing according to claim 7 or 8 , wherein the plate thickness is added to the temporary three-dimensional surface and the three-dimensional surface is displayed on the display unit . A storage medium storing a program to be executed. The computer is
When the inner loop of the arrow view is extracted all the steps of each arrow FIG sequentially extracts the pair of parallel line segments in each loop,
And determined Mel step the vertical distance of the line segment parallel to each other,
Comparing each vertical distance of each inner loop, and setting the inner loop having the narrowest distance interval as the first inner loop ;
Storage medium storing a program for creating a three-dimensional view of the claims 6-9, wherein the sheet metal CAD drawing for executing a thickness calculating step including.

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