
	Eg 2: SUBD Texture Maps

Once the surface has been fitted to your liking, you'll next want to define the texture map information. But first, the network should be saved out to a SLICE file, the full detail polymesh loaded, and the saved network reloaded.

Figure 219. Texture Maps Panel

To define texture map parameters, the Texture Maps panel is opened up (see Figure 219). From there you can step through each individual patch and edit map settings one at a time. But by far the easiest thing to do is use the auto define buttons:

(1)

Click on the right blue arrow to pick the first patch.

(2)

Enable the Pow 2 check box, as this will often produce more compact uv mappings (i.e. less wasted background space).

(3)

Enable the types of maps you want to render out. In this example its both Disp and Color.

(4)

Click on All Type to assign the selected patches map outputs to all patches.

(5)

Click on All Size to calculate and assign the optimal pixel dimension to all patches.

(6)

Click on All Err to calculate and assign the maximum surface error to all patches.

Once that process is complete, you should click on Sel Max to find which patch has the maximum surface error, then click on the blue Max Error button to recalculate the error for that patch.

Figure 220. Maximum Error Patch Selected

Because you are now calculating the error for a selected patch, Iview is run and loaded with a preview image of the displacement for that patch (see top right of Figure 220). The preview image often starts off a touch too small to see clearly, so you might need to enlarged the Iview window and hit <z> a few times to zoom in.

You could then type <Ctrl-h>. to view the grey levels histogram (see bottom right of Figure 220). The histogram can often give you more information about the grey level distribution in the image, and in particular, does it overflow to white, or underflow to black.

In this example, the maximum error patch is inside the ear, with a displacement error of 1.1 mm; that's probably a touch too ambitious. Even though the histogram indicates the minimum pixel value is 8 (in the range 0 to 255), the trend looks like is going to head below zero, suggesting a potential under flow when the full detail map is calculated.

If you think the error values might be heading outside the normal 0 to 255 range, then increase the maximum error for the selected patch. In this example, an error of 1.5 mm is probably more appropriate.

Remember: If you change any map parameter for the selected patch, make sure you hit <Enter> in the input field to assign that value.

Once you are happy with the map settings, click on the green Build UVs button to assign texture UV coordinates to the SUBD control hull. The final map size if calculated and written into the Total Size field. If this looks too small or large for you application, then change the percentage field and hit Build UVs again to recompute the size.

Figure 221. Texture View

Figure 221 is a screen capture of Maya's "Texture View" window, showing the UV coords for the example Killroo SUBD head surface. Viewing of UVs can now be done within CySlice itself with the Texture Maps View UVs button.