Apparatus and methods for wrapping texture onto the surface of a virtual object
View Patent ↗The invention provides techniques for wrapping a two-dimensional texture conformally onto a surface of a three dimensional virtual object within an arbitrarily-shaped, user-defined region. The techniques provide minimum distortion and allow interactive manipulation of the mapped texture. The techniques feature an energy minimization scheme in which distances between points on the surface of the three-dimensional virtual object serve as set lengths for springs connecting points of a planar mesh. The planar mesh is adjusted to minimize spring energy, and then used to define a patch upon which a two-dimensional texture is superimposed. Points on the surface of the virtual object are then mapped to corresponding points of the texture. The invention also features a haptic/graphical user interface element that allows a user to interactively and intuitively adjust texture mapped within the arbitrary, user-defined region.
1. A method for wrapping a texture onto a surface of a three-dimensional virtual object, the method comprising the steps of:
(a) providing an arbitrarily-shaped user-defined region of a surface of a three-dimensional virtual object, wherein a boundary of the user-defined region may be curved;
(b) for each of a plurality of locations in the region:
(i) mapping the location in the user-defined region to a corresponding location in a texture; and
(ii) assigning to the location in the user-defined region a graphical value associated with the location in the texture;
(c) graphically rendering the virtual object with the texture applied within the user-defined region; and
(d) updating, in real-time, the graphical rendering of the applied texture in response to direct user interaction with the surface of the three-dimensional virtual object.
2. The method of claim 1 , further comprising the step of: (e) modifying a voxel representation of the virtual object according to the graphical values assigned in step (b).
3. The method of claim 1 , wherein the texture comprises a tiled pattern.
4. The method of claim 3 , wherein no boundary of a tile of the tiled pattern is constrained to align with a boundary of the user-defined region.
5. The method of claim 3 , wherein step (c) comprises graphically rendering the virtual object with the tiled pattern applied within the user-defined region.
6. The method of claim 1 , wherein the graphical value is a color value.
7. The method of claim 1 , wherein the texture comprises an embossing pattern and wherein the graphical value represents an adjustment along a normal to the surface of the virtual object.
8. The method of claim 7 , wherein step (c) comprises graphically rendering the virtual object with the embossing pattern applied within the user-defined region.
9. The method of claim 1 , wherein the three-dimensional virtual object comprises a geometric representation selected from the group consisting of a NURBS patch, a Bezier patch, a Cardinal spline patch, a Gregory patch, and a bicubic patch.
10. The method of claim 1 , wherein the user interaction with the surface of the three-dimensional virtual object comprises an adjustment of a position of the applied texture on the surface of the three-dimensional virtual object.
11. The method of claim 1 , wherein the user interaction with the surface of the three-dimensional virtual object comprises an adjustment of a scale of the applied texture on the surface of the three-dimensional virtual object.
12. The method of claim 1 , wherein the user interaction with the surface of the three-dimensional virtual object comprises an adjustment of a rotational position of the applied texture on the surface of the three-dimensional virtual object.