Mapping of two-dimensional surface detail on three-dimensional surfaces

In a computer-aided design system, a method of mapping two-dimensional pattern images onto a three-dimensional surface displayed on a graphic display, comprising:

• generating a three-dimensional mesh conforming to the topology of the three-dimensional surface, said mesh including lines intersecting at nodal points, said lines forming polygonal elements between nodal points, the distance between said nodal points corresponding to the three-dimensional topology of the surface;
• converting said three-dimensional mesh to a two-dimensional pattern mesh, said two-dimensional pattern mesh having a pattern outline, a plurality of polygons corresponding to said polygonal elements, each of said polygons having edges corresponding to said lines between nodal points of said polygonal elements, the length of said edges directly corresponding to the distance between nodal points defined by the three-dimensional topology of the surface;
• generating a bitmap image corresponding to the two-dimensional pattern image to be mapped, said bitmap image including a plurality of texture pixels;
• orienting said two-dimensional pattern mesh upon said bitmap image of the pattern image such that said pattern outline is orientated according to the pattern image to form a bitmap pattern piece image thereby ensuring said pattern mesh is an accurate representation of said bitmap image;
• and
• mapping said bitmap pattern piece image to the displayed three-dimensional surface according to the configuration of said polygonal elements of said three-dimensional mesh to form a dimensionally correct image of the pattern image on the displayed three-dimensional surface by interpolating a number of pixels along an edge span of said polygonal elements extending between opposing edges of said polygon and mapping said texture pixels of said bitmap image onto said edge span in correspondence to said interpolated pixels until said polygonal elements are filled with said texture pixels and all of said polygonal elements within said pattern outline have been interpolated and mapped, said edge span having a defined length corresponding to the three-dimensional topology of the surface, each edge span having an identical number of pixels interpolated and mapped thereto.

In a computer-aided design system, a method of mapping a bitmap pattern piece image corresponding to a two-dimensional pattern image, the bitmap image including a plurality of texture pixels, onto a three-dimensional mesh conforming to the topology of a three-dimensional surface displayed on a graphic display, the three-dimensional mesh represented by a two-dimensional pattern mesh having a pattern outline, a plurality of polygons configured proportionate to the topology of the three-dimensional surface, each of the polygons having edges with a length directly corresponding to the three-dimensional topology, comprising:

• assigning each edge of said polygons of said pattern mesh to an edge structure corresponding to a positional relationship of said polygonal relative to other polygons within the two-dimensional pattern mesh defined by two-dimensional positional coordinates;
• scanning said edge structure to locate two opposing edges of a single polygon, said opposing edges of said single polygon forming a plurality of edge spans therebetween;
• interpolating a number of pixels along one of said edge spans based upon a length of said edge span relative to the three-dimensional topology of the surface represented by a configuration of said single polygon, said interpolation accomplished by computing an actual pixel index in the bitmap image corresponding to the texture pixels along said edge span to determine a mapping position of said texture pixels according to the three-dimensional topology and computing color components of the texture pixel along said edge span, said color components being attenuated according to the three-dimensional topology and a light intensity falling on the three-dimensional surface corresponding to said edge span;
• mapping said texture pixels of said bitmap image onto said edge span in correspondence to said interpolated pixels;
• and
• recursively repeating said interpolating and mapping steps until each edge span has been mapped and recursively repeating said scanning, interpolating and mapping steps until each polygon within the pattern outline has been filled with the texture pixels thereby forming a dimensionally correct image of the pattern image on the displayed three-dimensional surface based upon the two-dimensional pattern mesh, the two-dimensional pattern mesh determining a texture mapping to the three-dimensional surface.