If you use weight maps on subpatch objects for texturing, you'll want to pay attention to this pitfall. If you never use subpatches, ignore this. And anyway, hopefully this will be fixed in version 6.1.
In Figure 1 we see 2 weight maps on a subdivided plane as viewed in Modeler. They look identical, but in fact there is a fundamental difference, and in Layout they will perform quite differently. The weight map on the left contains 4 points, all at 100%. The weight map on the right contains 4 points at 100%, plus the adjacent 12 points at 0%.
Figure 1:
First lets look at how these weight maps perform on non-subdivided surfaces. In layout I imported the two planes and textured each with a color gradient, using weight map as the input parameter. Since the weight maps contain values from 0 to 100, I created a white key at "parameter 0" and a red key at "parameter 100".
Figure 2:
As Figure 3 shows, these weight maps perform identically, mimicking how they appear in Modeler.
Figure 3:
Now lets see how they perform on subpatch objects. Lets look at two cases. One in which the subpatch level for each object is set to zero, the other where the subpatch level is six. With the Subpatch at zero (or one), the two maps perform identically, with an outcome similar to what we see in Modeler. It is when the subpatch is set higher than one that the difference in weight maps becomes apparent. The weight map with only 4 points at 100% no longer appears as it does in Modeler. Your textures will abruptly come to an end, fading to zero in the brief span of a single subpatch. The weight map with the zeroed points, on the other hand, performs perfectly, with color fading all the way to the zeroed points.
Figure 4:
So lets say you've already set up a bunch of weight maps for a subdivided object and you didn't create a ring of 0% points. There is a (sort-of) fast way to solve this. Open your object in Modeler. Select the weight map you wish to change (Press the "W" button in the lower right hand corner of the screen and select the map from the popup menu). Next select all the points in the map using "SelectByMap". (If you have trouble finding any of these options, go to Preferences:Edit Menu Layout and for god sakes map these options to someplace you can get to fast!) Third, "Expand Selection", or "shift-]". This will select all the points adjacent to the points in your map. Now use "SelectByMap" to DESELECT the points in the map. Now you are left with only the points ringing the map. Assign these points a map value of 0% using "Set Vertex Map Value". You have just added these points to your weight map...
There may be some situations where you want a sudden transition in your texture, and then perhaps you wouldn't want to set a ring of 0% points. But of course if a sudden transition is what you are after, you can achieve this with a much greater degree of control and flexibility by adding more keys to your gradient in the surface editor...
The pitfall outlined in this tutorial is not a problem when using endomorphs or weight maps with bones as long as you set your subdivision order to "after displacement" or "after bones", respectively.
Dug Stanat