EP1787263A1

EP1787263A1 - Mesh design method and tool

Info

Publication number: EP1787263A1
Application number: EP05775913A
Authority: EP
Inventors: Sébastien DEGUY
Original assignee: Allegorithmic SAS
Current assignee: Allegorithmic SAS
Priority date: 2004-08-10
Filing date: 2005-08-03
Publication date: 2007-05-23
Also published as: WO2006015781A1; US20080211807A1

Abstract

The invention relates to a mesh design method which is used to generate or modify a mesh (60) of an input set comprising a plurality of basic geometric shapes (61). The inventive method comprises the following steps consisting in: (a) introducing the data forming the mesh (60) to be processed into a mesh modification tool; (b) introducing the parameters of at least one modifiable procedural map (50), which is intended to produce a spatial cursor, into a procedural card generation or modification tool; (c) generating the procedural card (50) using said procedural card generation or modification tool; (d) matching the different points of the procedural card(s) (50) with the corresponding parameters or points of the mesh (60); and (e) rearranging at least part of the points of the input set as a function of the data supplied by the procedural card(s) such as to generate a modified spatial arrangement for at least part of the basic geometric shapes. The invention also relates to a corresponding mesh design tool.

Description

Mesh design tool and method

The present invention relates to a tool and method of mesh design, which can be used in most areas where meshes are present, such as for example the modeling of images or objects, video games, video in general, industrial design, etc.

A large number of three-dimensional applications are wholly or partially realized with mesh. This mode of image construction is very practical and has many advantages, such as for example being able to dress the same mesh in several different ways, thus making it possible to easily and quickly generate several objects the basic structure is identical or similar.

On the other hand, in the many cases where an existing mesh must be modified, the manipulations to be carried out are generally tedious and expensive. You must either start again or rebuild a new mesh, or manually change each of the points you want to reposition, manually adding any additional points needed to enrich the mesh base. In cases where many objects are to be treated, the costs generated can easily become prohibitive.

To overcome these drawbacks, the present invention provides a mesh design method for generating or modifying a mesh of an input assembly comprising a plurality of elementary geometric shapes (such as for example triangles) describing a surface in a three-dimensional space according to an initial spatial arrangement on which the procedural map is operable to modify said arrangement, comprising the steps of: a. -Introduce the data constituting the mesh to be processed in a mesh modification tool; b. -input the parameters of at least one modifiable procedural map intended to produce a spatial cursor in a tool for generating or modifying procedural maps; vs. generate the procedural map using said modifiable procedural map generation or modification tool; d. performing a mapping between the different points of the procedural map (s) (or spatial cursor) and the corresponding points or parameters of the mesh; e. -Re-arranging at least a portion of the points of the input set according to the data provided by the one or more procedural maps so as to generate a modified spatial arrangement for at least a portion of the elementary geometric shapes.

According to an advantageous embodiment, the re-arrangement of the points is controlled by at least one modifiable procedural map including indications relating to a direction and a distance for the points to be moved.

According to various embodiments, these indications can be contained either in a single card or in several cards (for example a card with direction vectors and a card with distances or lengths). According to another variant, the direction vectors are normals at the surface defined by the mesh.

Each of the points of the initial spatial arrangement is likely to be moved in the direction indicated by the spatial cursor. This direction can be selected from a plurality of directions in space. In general, it can be any angle (any angle); according to a particular embodiment, said angle is an orthogonal angle. Note that each point can be moved independently (and therefore differently) from others.

Advantageously, said card is a procedural map, with a tree structure, comprising a plurality of stages, each with at least one node, said card being intended to produce a spatial cursor, which is associated with at least one parameter.

Advantageously, the method further comprises a subdivision step of subdividing at least a portion of the elementary geometric shapes. The subdivision factor can be fixed and at least 2, but is advantageously selected by the user depending on the context.

The subdivision step consists for example of: a. check if the subdivision stop criterion is reached; b. if the criterion is not satisfied, perform at least one subdivision and return to step (a); vs. if the criterion is satisfied, discontinue the subdivision.

According to various embodiments, either one subdivide once and move the newly introduced points, then resubdivise again, and so on, or, in cases where the subdivision criterion does not depend on the position of the points, performs all the subdivisions first, then moves all the new points for which a displacement is planned.

The subdivision stop criterion can be a threshold, a minimum, and so on.

The possibility of making one or more subdivisions of at least a portion of the mesh to increase the number of elementary geometric shapes is particularly interesting. It allows to use a simple starting grid, which can subsequently be completed appropriately to perform tasks more complex than those allowed by the simple starting grid. The subdivision thus makes it possible to generate the additional points that make it possible to adjust the complexity or density of the mesh as a function of the level necessary to achieve the desired result. Such automatic subdivision allows considerable time savings, since manually making such additions of points is very long and very tedious. A test makes it possible to check, for example, whether the desired mesh does or does not require the addition of new points. For example, one can check if the deviation from the theoretical result (that which would be obtained if one carried out an infinity of loops of subdivisions) is acceptable. Otherwise, according to another embodiment, if a test is independent of the position of the points, it can then be checked whether the number of elementary geometric shapes is at least equal to that which the user needs.

According to an advantageous embodiment, a threshold is set, for example as a function of the number of elementary geometric shapes and or the desired precision, or the fineness of the subdivision, etc. As long as the threshold is not reached, new points are added by subdividing the elementary geometric shapes. Depending on the case, the subdivision may concern all the elementary geometric shapes, or only a part of them.

Advantageously, the method according to the invention takes place with a display of the mesh. The mesh is thus preferably displayed at all stages, ie before it is modified, during and after modification. According to an advantageous embodiment variant, the display makes it possible to display the mesh and the procedural card or cards arranged on the mesh, with correspondence of the points. Such a visualization can be facilitated for example by coloring the mesh according to the card.

Advantageously, the method according to the invention takes place with a display of at least one of the procedural maps implemented, or at least a portion thereof. Such a display is very useful for adjusting the parameters of a card during work. In addition, in the case where a card or several cards must be modified, such a display is particularly useful.

Advantageously, the method according to the invention comprises one or more steps of modifying the procedural map / spatial cursor. After map modifications, one can then proceed directly to the stage of rearrangement of the points of the mesh.

One or more procedural maps can be modified before or after points of the mesh have been rearranged. Preferably, the manipulation of the selection of the portion of the mesh to be modified is performed from the mesh display window. The user may also be able to view the operations performed by a representation of the map on the mesh that reflects the changes in progress. The displacement calculations are preferably carried out at the end of the modifications, (and actuated for example using a command "creation of the mesh") so as to optimize the necessary calculation time. Thus, the mesh display window -presenting both the mesh and the map applied thereto- advantageously makes it possible to display the representation of the modified procedural map, substantially as the modifications are made.

The work done in the window of visualization of the mesh makes it possible to obtain a tool and a mode of work very ergonomic, very visual and thus very practical for the user. Indeed, if the modifications in progress are not presented or presented only in the procedural map display window, the user may have some difficulty in imagining the result of these modifications on the mesh.

According to an advantageous embodiment, the spatial map / cursor depends on the time. This embodiment makes it possible to create structures that vary as a function of time. In such a case, the subdivisions must be made before traveling. Thus, the position of the points of the mesh depends on the time, but the number of elementary geometric shapes and the topology are preferably independent of time. According to an advantageous embodiment, the mesh is generated by a mesh generator, for example during the introduction of the data / parameters of the latter to the mesh modification tool.

According to various embodiments, various tests may be applied to prevent the points or vertices being deployed beyond a useful limit, from which they are no longer visible. Indeed, it is generally useless to position points in non-visible places. This causes unnecessary losses of computing resources and memories. It is thus possible to check for each elementary geometric form if it forms an intersection with another. To minimize the time required, it is often more practical and sufficient to perform this type of test only for a limited number of elementary geometric shapes, for example those located in a given neighborhood.

The invention further provides a mesh design tool for generating or modifying a mesh of an input assembly having a plurality of elementary geometric shapes (such as triangles) describing a surface in a three-dimensional space according to a spatial arrangement. initial state on which the procedural map is capable of acting to modify said arrangement, said tool comprising:

an input unit of the mesh, for receiving the data corresponding to a mesh to be modified;

a tool for generating or modifying procedural maps making it possible to generate procedural maps having a tree structure, comprising a plurality of stages, each with at least one node to which at least one parameter is associated, intended to produce a spatial cursor, comprising:

a card parameter input unit, for receiving predefined procedural card parameters taking into account the data of at least one input set on which the spatial cursor will act in order to modify the initial spatial arrangement; a processing unit for processing said parameters, so as to generate said spatial cursor map, so that the map has a tree structure;

instructions for implementation, to ensure the operation of the tool and in particular of the processing unit;

an output, making it possible to transmit the generated cards, an integrator, capable on the one hand of matching the different points of the spatial cursor with the corresponding points of the mesh, and on the other hand of re-arranging at least a part points of the input set according to the data provided by the one or more procedural maps so as to generate a modified spatial arrangement for at least a portion of the elementary geometric shapes.

Since the procedural maps with tree structure are modifiable, the tool according to the invention gives the user a very great flexibility of work. Thus, changes can be made easily and quickly, with an appropriate tool, rather than manually.

The tool according to the invention advantageously comprises, during its implementation, a display window of the mesh, capable of presenting the mesh to be modified (preferably before, during and after integration).

The tool preferably includes a node selection tool for selecting at least one node of a stage.

Such a tool can be implemented either through the procedural map display window, or through the window for viewing the mesh. It allows for example to move a selected portion and / or change the parameters of one (or more) procedural map associated with this selection only. The rest of the map can either remain unchanged or be modified according to other parameters. According to an advantageous variant embodiment, the mesh design tool also comprises:

a tool for selecting and modifying card parameters, in order firstly to select a parameter to be modified, and secondly to allow the entry of the new value of the parameter;

a processing unit for processing said parameters so as to generate said modified spatial cursor map;

instructions for implementation, to ensure the operation of the tool and in particular of the processing unit; an output, making it possible to transmit the modified card.

The node selection tool advantageously comprises a depth selection unit, making it possible to select the extent of the modification to be made on the shaft. According to another exemplary embodiment, it comprises a mobile node-object location frame. The frame can be controlled by a cursor directly from the work interface.

According to another advantageous embodiment, the mesh design tool, also comprising a mesh generation module. Such a module can be arranged to cooperate with the mesh input unit. The user thus has a tool allowing him to create a mesh, which is easily modifiable later with the other elements of the mesh modification tool.

The invention will be described with reference to FIGS. 1 to 24 attached, presented solely by way of non-limiting example, in which:

FIGS. 1a, 1b and 1c illustrate the basic principles for the mapping between the points of the procedural maps and the corresponding points of the mesh to be modified; FIGS. 2a and 2b show the main steps of two embodiments of the method according to the invention; FIG. 2c illustrates the main functional elements of the tool according to the invention during its implementation;

FIGS. 3 to 8 show on the one hand the working interface of the tool according to the invention, and on the other hand the various steps making it possible to modify a mesh from an modifiable procedural card;

FIGS. 9 to 14 illustrate various examples of tree structures for procedural maps, example parameters and examples of modifications; FIGS. 15 to 19 show different examples of procedural maps with a tree structure; FIGS. 20 to 23 show examples of modifications made to modifiable procedural maps;

FIG. 24 illustrates an exemplary interface for a tool for generating and / or modifying procedural maps with a tree structure.

The present invention is based on the use of procedural maps with tree structure. Figures 9 to 14 illustrate examples of such trees (for the specific case where n = 1, where n is the size of the support, for example, n = 2 for an image, n = 3 for a volume, n = 1 for a curve). In the example of Figure 9, at j = 0, there is a single node. Two child nodes or sons are at level j = 1, and four at level j = 2. All nodes are similar. The F function contributes a lot to the definition of the basic form of the object-node. It is also referred to in this document as "morphlet". A morphlet can take virtually any form. Such a procedural map with a tree structure can be represented by the following equation:

Σ Σ F (2 ^j x - k), (j, k) jk

forming a tree T, and also represented in document by: Σ F (2 ^j x - k) G - k) eT

in which:

-F is a function or morphlet R ⁿ → R

-x is a vector of the type (X ₁ , X ₂ X _n );

-T is a tree comprising nodes (j, k) and in which

-j indicates the current level, among a total potential number of levels jmax (j e (0, 1, 2 jmax);

-k is a displacement vector for each node N and of the type (xi, X ₂ i Xn) •

Figures 9 to 14 illustrate examples of local modifications that can be achieved through the tree structure of the invention. For example, in Figure 10, different values of H have been assigned. Thus, the left half-shaft of FIG. 10 has a value of H of 0.2; the one on the right, a value of H of 0.8.

The shaft is symmetrical but the invention makes it possible to produce unsymmetrical shafts. This type of modification can make it possible to locally modify the roughness level of a card: by tending towards H = 1, a surface will be smoother; tending towards H = O, a surface will be rougher.

In Figure 12, some subtrees or branches are deleted. Parameter P represents a probability of removing branches from a tree. With p = 0.2, there is a probability of o, 2 to remove branches; for p = 0.8, this probability is 0.8. This parameter can be adjusted to maintain or not a high density of subtrees.

Figure 13 illustrates the possibilities offered by the parameter D, the offset. The offset moves one or more nodes from their original positions. Finally, FIG. 14 illustrates the major types of parameters with which the invention makes it possible to work to create or modify procedural maps: the action parameters such as p and D, and the structure parameters, such as H, F and ξ.

Figures 15 to 19 illustrate examples of procedural maps having tree structures. For example, Figure 1 shows an example in which a morphlet of type F = 1, if X2 + y2 <1, otherwise, F = O. At j = 0, with a simple node, a simple NO object node is generated, taking the form of a uniform and centered disk (Figure 15).

For j = 1, at the second level, Figure 16, there are four node-objects, in this example, four smaller disks, each being uniform. This layer is thus divided into four sections, each forming a node-object. Each section occupies VA of the initial map, according to the quadratic and uniform type arrangement of this example. We thus see the effect of the main parameters: j indicates the current level, k allows the displacement of node-objects, in this example from the center of the map towards the center of one of the quarters. The basic morphlet F remains unchanged.

The following figure (Figure 17) illustrates the 3 ^Θ level 0 = 2), for the same morphlet. Since the previous level, there is a new subdivision in 4 quarters, each quarter having its node-object, in this example, a similar disc, but always smaller.

Figure 18 shows the sum of these different layers. This very simple example makes it possible to visualize the basic forms of each level. Figure 19 illustrates a sum of the same type but for a higher number of levels, therefore a higher number of node-objects, hence a more complex structure in this example. EXAMPLES OF MODIFICATIONS

Figures 20 to 23 illustrate examples of map modifications that can be made using the method and tools of the invention. In FIG. 20, the mobile frame 23 of the node selection tool 20 is located on an object node 51 to be processed. The following figure shows the result after deleting this node. We see very well that the changes can be made at a local level, without affecting the rest of the map.

Figures 22 and 23 illustrate a similar process of changing the parameters at a node. In this example, the function or morphlet F has been modified, thereby affecting the basic form of the node-object of this quarter map. Indeed, we see in Figure 23 the disks of Figure 22 which are now thinned or crushed.

FIG. 24 illustrates an example of a working interface obtained by a tool 10 for generating and / or modifying procedural maps with a tree structure. According to various embodiments, such a tool can be provided either for the modification of existing procedural maps, or for the generation and modification of such maps.

The basic tool includes a node selection tool, including a J-level selector 21, and a node selector, allowing the selection of a given node in the selected level. In practice, as described below, the user selects a layer, corresponding to a given level J and a node object, corresponding to a node K.

The tool 10 includes a parametering tool 30, for selecting a parameter, either to give it a first value, or to modify or adjust it, as the case may be. To modify a map, one or more nodes 41 are first selected. A tool such as the node selector 20 offers this possibility. Such a tool can advantageously provide two functions: a level selection unit 21, and a node selection unit. The node selection tool comprises a mobile screen target 23. This target is advantageously configured so as to allow delimiting at least one object node 51 in a given layer. In the illustrated examples, the target is substantially square in shape. To facilitate the selection of the nodes, the tool includes a mode of displacement so as to allow the self-positioning of the target on a node-object or on a set of node-objects, for example the nearest nodes, when the target is not perfectly positioned by the user on a node. The target can be controlled by any type of conventional control of a computer, such as a mouse, a pointer, keyboard keys such as arrows, or a remote control such as a machine, a specially designed circuit or a control software . It can also be controlled directly from the interface of the node selection tool, for example by means of a cursor 24 controlling the movement of the target 23 on the card.

Advantageously, the tool 23 is configured so that when a level is selected, the shape and size of the frame 23 adapts to those of the object node 51 of the corresponding level. The tool 23 makes it possible to select any node of the selected level.

According to another variant, the node selection tool 20 comprises highlighting means, making it possible to indicate to the user which nodes are selected. Such an indication may be made by color or intensity change, flashing, or any other effective visual means.

The tool 10 preferably includes a depth selector 26, allowing the user to indicate whether the current operation only concerns the nodes of the selected level or whether the subtrees should also be treated in a similar manner. The parametering tool 30 first makes it possible to select a parameter to be considered. Then, its new (modified or initial) can be entered. The tool is advantageously adapted so as to be able to process at least one, but preferably all types of parameters illustrated in this document, such as: F: 34, H: 35, ξ: 36, p: 33, D (x) : 31, D (y): 32.

The interface allows the user to give a value to the different parameters. For example, for F, the user enters a function, such as the one illustrated. According to one variant, a drop-down menu can offer the user a series of functions from which he can choose. It is the same for the parameter ξ. For the parameter p, the user gives a value, for example between 0 and 1, for example using a cursor or other similar tool. A drop-down menu can also be proposed. For parameters H and D (for x and y), in the case where the user chooses the internal mode, the values can be entered in a manner similar to that of the parameter p, with values for example between 0 and 1 for H , and as a percentage for D. A time scale 70 representing the time makes it possible to work with cards whose parameters may be called to vary as a function of time.

Procedural maps in tree structure and mesh

Figures 1a, 1b and 1c show the basic principle upon which the present invention is based. This example is deliberately very simple for demonstration purposes. It goes without saying that many applications in the field of computer graphics involve meshes and procedural maps more complex. A mesh 60 consisting of a number of elementary geometric shapes 61, has an initial spatial arrangement. The information or data used to modify the position of at least one of the elementary geometrical shapes 61 are provided by one or more procedural maps 50 with a tree structure 40. In the example of FIG. 1a, eight triangles 61 are arranged in a plan to form a square. The procedural map 50 must contain at least the repositioning information for the points to be moved. The card 50 therefore has different information in its upper left portion, corresponding to the points to be moved, those of the rest of the card, corresponding to points that we do not want to move. FIG. 1b shows the correspondence between the sections or regions or points of the procedural map 50 of instruction or positioning calculation, and the different points of the mesh 60 to be modified. For each point of the mesh corresponds a point of the map. In this example, the pairing of the points corresponds simply as if the procedural map were superimposed on the initial mesh. The arrows of correspondence of Figure 1b illustrate this aspect.

When the mapping is done, the data used to reposition the points of the mesh 60 have been transferred or sent to the computer. In this theoretical diagram, we illustrate the transposition of the map to the mesh. In practice, a means or calculation tool is required to read or interpret the positioning data of the card and establish the new position.

Figure 1c shows the result of the calculation performed to reposition the points to move. The displacement information contained in the map has been applied to the mesh 60. It can be seen that the pale portion of the map 50 containing non-zero values has allowed the repositioning of a corresponding portion of the points of the mesh 60, as a function of the values contained therein. in the map.

The repositioning data can be provided in any format for establishing a new position, for example using vectors. As such, several additional procedural maps may be useful for providing the data. For example, a map for distances, and one for angles or directions. In the example illustrated in FIG. 1, the displacements are orthogonal; only a distance map is sufficient to establish the new positions. Figure 1c also shows examples of displacement values for points that have been repositioned. Procedural maps therefore act as spatial cursors, making it possible to redefine the positions of different points of a mesh to be modified.

Figures 2a and 2b show functional diagrams for illustrating the different steps of the method according to the invention. A starting mesh 60 is considered in order to make modifications. A procedural map 50 is established by the user. This card contains the parameters or data relating to the movements of the points to be made. A mapping step makes it possible to match the points of the card 50 with those of the mesh 60. The transmitted data then make it possible to carry out distance calculations and possible direction calculations (for cases where the displacements are not not orthogonal). The step of moving the points can then be performed. A modified mesh is thus obtained.

According to an advantageous embodiment, the method and the tool according to the invention make it possible to modify the procedural card or cards. The map is modified by the user, using tools that are described later in this document. From this modified map, applied to the starting grid, the distances and directions calculations are carried out, making it possible to proceed with the displacements of the points of the mesh. A new mesh is then obtained. This new mesh can of course be modified again, as many times as necessary, to obtain a satisfactory result.

Although FIG. 2a shows the calculation and displacement steps as being carried out successively, they can be performed in parallel, or in a different order. Of course, the moving step is advantageously performed at the end of the process, to allow the prior obtaining of all the data necessary to perform these movements. FIG. 2b shows an advantageous variant of FIG. 2a, furthermore comprising one (or several) subdivision steps of the mesh 60. It is indeed common that the basic mesh is not dense enough to obtain the desired result. from the travel data provided. Rather than manually adding the missing mesh points, the method and the tool according to the invention make it possible to enrich or increase the density of the mesh by adding, using an iterative process, missing points. This very advantageous feature of the invention is described in more detail later in this document.

Figure 2c shows the various functional elements used in the implementation of the invention. An integrator 100 receives on the one hand the data of an input unit 102 of the mesh 60, and on the other hand the data of a tool for generating and / or modifying 103 of procedural card. The integrator 100 includes calculation instructions enabling it to map or match the cards with the mesh. It also includes calculation instructions enabling it to calculate the distances and possible directions, in order to proceed with the displacements of the points of the mesh for which information relating to a displacement has been provided.

The resulting mesh is preferably stored by a backup unit 104 of the mesh.

Integrator 100 also plays a key role in cases where a card needs to be modified. Advantageously, it makes it possible to manage or to carry out these modifications starting from the window of visualization of the mesh. Information about the changes made is passed to the map generation / modification tool, which generates the new map with these changes. Finally, the integrator makes it possible to calculate distances and possible directions for a modified map. The movements of the corresponding points can then be made. FIG. 3 illustrates an example of a working interface 110 of such an integrator 100. The illustrated example has two viewing windows: a first window 111 for displaying the card 50 or at least a portion of a card in progress. use, and a window 112 for viewing the mesh. According to an advantageous embodiment of the invention, this second window 112 makes it possible to represent not only the mesh 60 alone, but also the assembly resulting from the mapping of the cards with the mesh. This aspect is particularly advantageous and facilitates and greatly enhances the work of the user who can view the elements for which he wishes to make changes.

Card parameterizing tools 130 are arranged on the working interface 110 and comprise, in the illustrated example: a "function" command 134 for entering or modifying the basic function of the procedural card used. A command 135 to enter or modify the value of H, and a command 125 to enter or modify the value of Jmax. Other commands making it possible to enter or modify other parameter values can also be used on this interface, for example the commands presented in the parameterization tool 30 of the interface of FIG. 24 (for the parameters Xi, D and p). Moreover, as in the interface of FIG. 24, the interface 110 of the integrator 100 may have a time scale in order to make it possible to establish one or more parameters that may vary as a function of time.

Tools 140 for integrating and calculating the mesh are also presented in FIG. 3. These tools comprise a selection control of the mapping mode 141 which makes it possible to choose from known modes, such as parameterization mapping. UV, spherical, cylindrical, cubic, planar, etc.

A subdivision command 142 makes it possible to establish the importance of the subdivisions to be realized. In the illustrated example, it is a division by 4. A displacement command 143 makes it possible to enter the mode (or angle) of displacement. According to one embodiment variant, this command is advantageously replaced by one or more procedural cards, especially in cases where the angles are not all the same for all points. In the illustrated example, it is a displacement according to a plane normal. A threshold command 144 for adjusting the subdivision threshold is also present. In the example, it is a cursor to select a value between 0 and the maximum threshold. Finally, the illustrated example includes a command button 145 to start the creation of the mesh, that is to say the step of moving the points.

The commands arranged under the mesh display window are advantageously dedicated to the options and tasks performed using this window. For example, in the example shown, a level selection command 121 selects which level or stage on the tree the current change is to be applied. A depth selector 126 also makes it possible to indicate whether the modification applies only to the current node or to all the nodes that depend on it (the child nodes).

Finally, the working interface preferably comprises a command "position of the camera" 150 for simulating a positioning of a camera relative to the object being worked. In the example shown, this command is used to select the viewing angles and the distance between the camera and the object.

In addition to the basic interface, FIG. 3 presents an example of a basic mesh 60 used as an input set, presented in the window 112 for displaying the mesh. The other window 111 shows an example of a procedural map 50 with a tree structure, which will make it possible to modify the basic mesh presented in FIG.

FIG. 4 presents the step of mapping between the points of the procedural map and those corresponding to the mesh, from the map and the grid presented in FIG. 3. The type of correspondence, the number of subdivision to be applied to the initial mesh as well as the type of displacement can be indicated by the user with the various integration tools 140 and mesh calculation provided on the working interface 110. The dotted arrows show how the points of the map are matched to those of the mesh. Once the mapping has been done, the command "creation of the mesh" 145 makes it possible to carry out the various calculations necessary to make the displacements of the points affected by the card.

The mesh display window 112 of FIG. 5 shows the mesh 60 once the movements have been made. This same figure also shows the selection tool 123 or target used to select a portion of the mesh on which the user wishes to make local changes. It selects the work stage and at which nodes the changes will apply, thanks to commands 121 and 126.

Figure 6 illustrates the next step of making the desired changes on the selected mesh portion. In this example, the user moves the selected mesh portion to position it at another location, as indicated by the dotted arrow. The working interface allows the user to work from the viewing window, which is particularly useful for visualizing the effect of current changes on the mesh. Figure 6 shows that at this stage, the new mesh is not yet calculated. The window has (within the target 23) an image of the section of the selected procedural map. Note on this same figure, the viewing window 111 of the procedural map that shows the modification made to the map.

In this example, the modifications are made and controlled from the window 112 for viewing the mesh. According to an alternative embodiment, the modifications can be controlled and performed from the viewing window 111 of the card. When the user is satisfied with the modifications made to the card, he can start the calculation for the creation of the mesh containing these modifications. FIG. 7 shows this step, in which the modified mesh is established, for example by activation of the command "creation of the mesh" 145. It is clearly seen in the figure the appearance of the vertical displacements in the portion of mesh that has been displaced. .

Finally, FIG. 8 illustrates the final result obtained once all the modifications have been made.

The exemplary embodiment of the integrator 100 has been described and presented with an interface 110 in which one finds both the working tools of the procedural maps and those relating to the mesh. According to various embodiments, the tool is split into different subsets. For example, it comprises a tool and an interface of the type of those of FIG. 24, used in parallel with a mesh management interface that does not have a card display window and card parameterization tools.

Claims

A mesh design method for generating or modifying a mesh (60) of an input assembly having a plurality of elementary geometric shapes (61) describing a surface in a three-dimensional space according to an initial spatial arrangement on which the procedural map is operable to modify said arrangement, comprising the steps of: a. -Introduce the data constituting the mesh (60) to be processed in a mesh modification tool; b. inserting the parameters of at least one modifiable procedural map (50) intended to produce a spatial cursor in a tool for generating or modifying procedural maps; c.-generating the procedural map (50) using said modifiable procedural map generation or modification tool; d. performing a mapping between the different points of the procedural card or cards (50) and the corresponding points of the mesh (60); e.-re-arranging at least a portion of the points of the input set according to the data provided by the one or more procedural maps so as to generate a modified spatial arrangement for at least a portion of the elementary geometric shapes.

2. The design method according to claim 1, wherein the re¬ arrangement of the points is controlled by at least one modifiable procedural card (50) comprising indications relating to a direction and a distance for the points to be moved.

The method of design according to one of the preceding claims, wherein said card is a procedural card (50), with a tree structure (40), comprising a plurality of stages (43), each with at least one node ( 41), said card being intended to produce a spatial cursor, with which at least one parameter is associated.

4. Design method according to one of the preceding claims, further comprising a subdivision step of subdividing at least a portion of the elementary geometric shapes.

The design method according to claim 4, wherein the step of subdividing comprises: a. Checking whether the subdivision stopping criterion is reached; if the criterion is not satisfied, perform at least one subdivision and return to step (a); if the criterion is satisfied, stop the subdivision.

6. Design method according to one of the preceding claims, further comprising a step of displaying the mesh.

7. The design method according to one of the preceding claims, further comprising a step of displaying at least one of the procedural maps implemented.

8. Design method according to one of the preceding claims, wherein modifying at least one procedural card.

9. Design method according to one of the preceding claims, wherein at least one procedural card depends on time.

10. The design method according to one of the preceding claims, wherein the mesh is generated by a mesh generator.

11. mesh design tool for implementing the method according to one of claims 1 to 10, for generating or modifying a mesh of an input assembly comprising a plurality of elementary geometric shapes describing a surface in a three-dimensional space according to a initial spatial arrangement on which the procedural map is operable to modify said arrangement, said tool comprising:

an input unit of the mesh, for receiving the data corresponding to a mesh to be modified; a tool for generating or modifying procedural maps (10) for generating procedural maps (50) with a tree structure (40), comprising a plurality of stages (43), each with at least one node with which it is associated at least one parameter, for producing a spatial cursor, comprising:

an input unit (30) for card parameters (31, 32, 33, 34, 35a, 35b, 36) for receiving predefined parameters of procedural cards taking into account the data of at least one set of input on which the spatial cursor will act to modify the initial spatial arrangement;

a processing unit for processing said parameters, so as to generate said spatial cursor map, so that the map has a tree structure;

an output, to transmit the cards produced; an integrator, able on the one hand to match the different points of the spatial cursor with the corresponding points of the mesh, and on the other hand to re-arrange at least a portion of the points of the input set according to data provided by the one or more procedural maps so as to generate a modified spatial arrangement for at least a portion of the elementary geometric shapes.

12. mesh design tool according to claim 11, comprising, during its implementation, a mesh display window, may have the mesh to be modified.

13. mesh design tool according to one of claims 11 or 12, further comprising a node selection tool (20) for selecting at least one node of a floor of a card.

The mesh design tool according to one of claims 11 to 13, further comprising:

a tool for selecting and modifying card parameters (30), firstly to select a parameter to be modified, and secondly to allow the input of the new value of the parameter (31, 32, 33, 34). 35a, 35b, 36); a processing unit for processing said parameters so as to generate said modified card;

an output, making it possible to transmit the modified card.

The mesh design tool according to one of claims 13 or 14, wherein the node selection tool comprises a depth selection unit (26), making it possible to select the extent of the modification to be made on the screen. 'tree.

The mesh design tool according to one of claims 13 to 15, wherein the node selection tool comprises a mobile node node locator frame (23).

The mesh design tool according to claim 16, wherein said frame (23) is controlled by a slider (21, 24) directly from the working interface.

18. Mesh design tool according to one of claims 11 to 17, also comprising a mesh generation module.