
	Templates: Copying Multiple Points

Multiple points are copied in a two stage process. First the Template and Target meshes are aligned, then each visible shape point in the Template mesh is snapped to the closest mesh point on the Target mesh.

Figure 141. Aligned Views

To get the meshes aligned, start off by adjusting the Template and Target views until the two meshes are oriented and positioned similarly in their respective windows (see Figure 141).

Figure 142. Multiple Copy Controls

When you are happy that the two views are matched, click on the Align button, found towards the bottom of the Templates panel (see Figure 142).

Figure 143. Aligned Points

You should then see a whole bunch of small black crosses appear in the Target mesh window; these are points sampled from the shape points, curves and patches in the Template window. Their initial positioning in the Target view will match their original positioning in the Template View (see Figure 143).

Figure 144. Refined Alignment

Unless you are very good, or just plain lucky, the crosses won't be fitted accurately to the target mesh. To get a better fit you can do one of two things: adjust one of the views and hit Align again to see if the fit gets closer, or click on the Refine button.

In the refinement process, the crosses are rotated and translated to minimize the distance between them and the target mesh. This will take a few minutes, but will give a much better fit than you could ever get by hand (see Figure 144).

If, for whatever reason, the refinment fails, slightly adjust one of the mesh views, click on Align again, and then Refine again. If after that it still fails to get a better fit, then don't worry too much; the point snapping, described next, will usually let you get away with any remaining alignment errors.

Figure 145. Points Copied

Once you are happy with the mesh alignments, click on Points to copy all visible shape points, and Seeds to copy all visible seed points from the Template to the Target mesh (see Figure 145). In previous versions of CySlice, a single Copy button was used to copy both sorts of points; this function has been split into two to allow for greater flexibility.

Figure 146. Remaining Curves Copied

At this point you might want to click on Copy Curves to copy the visible curves across. Its easier to see if the multiple point copy has worked by copying the connecting curves (see Figure 146).

Note: The default behaviour is to not scale points when they are group copied across; i.e. Scale Fixed (see top of Figure 142). This is important, for example, when mirroring points between two sides of the same head.
However, there may be situations when you do want the points scaled according to their relative size in the Template and Target windows. Say, for example, you wanted to copy a network from a child's face to that of an adult. In this case, make sure the child and adult heads are the same apparent size and enable the Scale Viewer button before copying points.

Then Copying Patches

If both shape and seed points are copied when you do the multiple point copying, you can Copy Patches as soon as you've copied the curves across.

Figure 147. Patches Copied

Figure 147 shows all points, curves and patches copied across.

One problem you might encounter is that some seed points in the multiple point copy process will end up outside their enclosing boundaries on the Target mesh. This is even more likely when you mix single and multiple point copy.

Figure 148. Patches Copied - Possible Problems

If you look closely at the top patch in Figure 148 you can see that there are two seed points in that enclosing boundary, and none in the enclosed boundary immediately below. This had occurred because the shape points in that area were copied one at a time, placed to closely follow the eye lid, and so the shape of the template and target curves is quite different. When the seed points were copied as a group, one of them didn't end up inside its enclosing boundary on the target mesh.

One way to avoid this situation is to copy potential problem seed points, one at a time, before you do the multiple point copy.

But by far the easiest solution is to do the multiple point copy, seed points included, then identify those seed points on the Target mesh that have ended up in the wrong place. Then, because you can't move seed points directly, you'll need to follow this procedure to re-locate them:

(1)

Delete the patch (right mouse click on seed point). The seed point gets turned into normal shape point.

(2)

Move that shape point.

(3)

Undel the patch you just deleted. It will be rebuilt in the new location, using the correct boundary curves.

Figure 149. Shaded Network and Template

Figure 149 shows the original template network (on bottom), and the final copied network (on top).