Evolutionary Direct Manipulation Of Free Form Deformation Representations For Design Optimization

Abstract

An improved method for optimizing a design, based on direct manipulations of the object points of a design. In addition, the number and modifications of control points is kept as minimal as possible while the targeted movement of object points is realized and the automatic adaptation and generation of a set of control points for deformations which allows the movement of object points to desired positions. One aspect of the invention is to generate the transformation function ƒ which is optimized to be able to realize desired changes of object parameters by means of control point variations. This optimization can be realized in a way that the mapping between the original coordinate system of the design and the spline coordinate system is not changed, so that no additional “freezing” process (the generation of the mapping between the coordinate systems) is necessary.

Description

BRIEF DESCRIPTION OF THE FIGURES

Further aspects and advantages of the invention will become apparent when reading the following detailed description in connection with the annexed drawing, in which

FIG. 1 shows the principle of constraint deformation: A 3D curve is computed from the original 2D curve, and projected twice to obtain two different deformed 2D curves.

FIG. 2 shows the principle of Free Form Deformation.

FIG. 3 shows the principle of EFFD: undisplaced (left) and modified (right) control points of an arbitrary control volume in accordance with one embodiment of the present invention.

FIG. 4 shows the Example of a B-spline-mesh and a T-mesh in accordance with one embodiment of the present invention.

FIG. 5 shows examples for T-spline simplification in accordance with one embodiment of the present invention.

FIG. 6 shows (left) knot lines for blending function and (right) T-mesh in accordance with one embodiment of the present invention.

FIG. 7 shows (left) a simplified configuration of a design object and a grid comprising object and control points and (right) the same configuration with a chosen target point and derived control points in accordance with one embodiment of the present invention.

FIG. 8 shows a flowchart of a method for optimizing a design according to the invention in accordance with one embodiment of the present invention.

FIG. 9 shows a flowchart of another method for optimizing a design according to the invention in accordance with one embodiment of the present invention.

FIG. 10 shows a flowchart of yet another method for optimizing a design according to the invention.

FIG. 11 is an illustration of the method shown in FIG. 10 in accordance with one embodiment of the present invention.

Claims

1. A computer-implemented method for optimizing a design, comprising the steps: representing the design, using a model and a grid, wherein the model includes object points, the grid comprising control points, and wherein the representation of the grid is variable and adaptive;choosing one or several object points;adapting the object points; andoptimizing the design by adapting the grid based on the object points.

2. The method of claim 1, wherein the adaptation of the object points increases or decreases the number of object points.

3. The method of claim 1, further comprising the step of: utilizing at least one of an evolutionary algorithm or a stochastic optimization to realize the adaptation of the object points.

4. The method of claim 1, further comprising the step of: selecting said one or several object points from object intervals or patches.

5. The method of claim 4, further comprising the step of: repeating the steps of choosing one or several object points, adapting the object points and optimizing the design, until an optimality criterion is met.

6. The method of claim 5, wherein the step of adapting the object points comprises the step of: adapting the object intervals or patches from which object points are chosen.

7. The method of claim 6, wherein the step of adapting the grid based on the object points increases or decreases the number of control points in the grid.

8. The method of claim 7, wherein the adaptation of the grid uses an evolutionary algorithm.

9. The method of claim 8, wherein the adaptation of the grid further uses a local search method.

10. The method of claim 7, wherein the adaptation of the grid uses a stochastic optimization algorithm.

11. The method of claim 10, wherein the adaptation of the grid further uses a local search method.

12. The method of claim 11, wherein the local search method is a least squares method.

13. The method of claim 6, wherein the step of adapting the grid based on the object points uses a least squares method.

14. A computer-based system for optimizing a design, the design represented using a model and a grid, wherein the model includes object points, the grid comprising control points, and wherein the representation of the grid is variable and adaptive; object point means for choosing one or several object points;adaptation means for adapting the object points; andoptimization means for optimizing the design by adapting the grid based on the object points

15. A computer software program product embodied on a computer readable medium for performing the method of claim 1 when run on a computing device.