
	Eg 5: UV Mapped Meshes

This example shows how CySlice can be used to surface UV mapped polymeshes.

Figure 244. HRC Polymesh

Figure 244 shows a dense polymesh, cylindrically mapped with an even denser 2k color map. The geometry and color in this example comes from a Cyberware HRC (High Resolution Color) head scanner.

Figure 245. SUBD Surface Construction

The surface fitting process proceeds exactly as described in previous tutorials. First the polymesh is reduced/decimated to speed up interaction, then feature curves are drawn, patches are added, the half is mirror templated to create a whole face, and the result is saved out to a SLICE file (see Figure 245).

Figure 246. Dense Polymesh Reloaded

Next, the original dense polymesh is reloaded, making sure that the UV color map is loaded as well. The SLICE file just saved out is then loaded up, and the surface is rebuilt (see Figure 246).

Figure 247. Default CySlice UVs

Then the patch by patch Texture Maps parameters are defined as usual, and Build UVs is evoked to assign the default CySlice UVs to the SUBD surface (see left side of Figure 247).
Because each patch's map resolution calculation is based on geometry density, not color map density, the overall map resolution will probably come out lower than the original map size. In this example, the calculated map size was 1k by 1k, but the original map was 2k by 2k.
In these situations the percentage value beside the Build UVs button should be increased so that the calculated map size comes out about equivalent to the original map size. In this example, the map was scaled by 200% to create a 2k by 2k map size.
The middle and right side of Figure 247 shows the rendered SUBD surface and new color map. Because the original dense color map is resampled, to match the new UV arrangement, there is some loss of crispness. And obviously the map looks more complex and would be much harder to edit in a 2D paint application.

Copying UVs

If the original color map could be used to texture the SUBD surface there would be no loss of quality; this is where the Copy UVs tool comes in handy.

Figure 248. Copied UVs

UVs can only be copied to an imported SUBD surface, so first the existing points/curves/patches based network is exported as a PLY file, then the network is deleted with Reset, then the PLY based SUBD surface is loaded back in.
Next Copy UVs is evoked and Poly selected because the UV source PLY is a polymesh (not a SUBD surface control hull). Then the dense polymesh is selected and opened from the Copy UVs file selection window.
Figure 248 shows the final result; the UVs have been modified so the original color map can be used in place of the CySlice resampled one.