One important, very simple tool in iClone and Character Creator is the Opacity map channel. I’m not talking about the opacity slider as that is more of a hammer on a gnat solution that removes everything from the view and the render. Rather I’m focusing on the Map Channel itself in the Texture Setting area of the Material panel.
More specifically I use them in both applications to eliminate layer poke through with clothing on character avatars. Poke through can be a big problem for some characters in everyday types of animations but the very bad offenders can ruin a render or hours of animation work.
Nothing like spending the evening animating a nice scene only to see it trashed by a chunk of white shirt poking through a dark jacket or worse, skin popping through tight-fitting clothing. Seems like it always happens in front of the camera too!
There are many reasons for poke through, but it’s generally related to decimation for a lower poly count. The problem is the underlying cloth mesh has fewer triangles than the layer over it meaning it has bigger triangles that cannot possibly bend at the same places as the smaller triangles above it forcing the mesh to poke through the upper layer. It simply has no other place to go.
In most cases… unless you want to rework the mesh… the opacity channel map for each body part or garment can be manipulated in an image editor like Photoshop to show or hide those parts. Even if the model is not broken down into sub-parts you can still alter the main map masking the areas you need to work with.
I keep a generic set of opacity maps in my texture folder, and it goes with me anywhere iClone or Character Creator is installed. I have a totally black map for those channels that will not show such as the body parts covered by clothing. If I’m lucky and it’s the entire body part like the torso then I’ll use the black map. Same for the legs if there are boots. I’ll use the black map whenever skin is not showing.
Results of Generic and Custom Opacity Maps to Hide Layers
Another important generic opacity map is for the arms and hands. This is when you need to be able to see the hands and parts of the lower arm extend from a shirt or jacket but not the rest of the arm. Same for the legs and feet if you need to see only a portion of the lower leg and foot. In some cases, an opacity map can be used to cut the top off of a hair mesh, so it looks like it fits under a cap or hat.
When I say generic, I mean just that. When using the character bases from Character Creator 3, I keep each type of opacity map (as I make it) in a folder within my textures so I can quickly load them up on other models that use the same base. If all I need to see are the hands and feet then I can load the generic maps until that is all that shows. These maps are very handy and a time saver.
Examples of Generic Opacity Maps. Black = Hide, White = Show
Any part of an object that has an opacity channel can be manipulated in this manner with these simple maps. Why worry about or even deal with poke through and related issues when you can simply manipulate the visibility of the underlying layer? Out of sight, out of mind as it won’t show in the final render anyway.
M.D. McCallum, aka WarLord, is an international award-winning commercial graphics artist, 3D animator, published author, project director, and webmaster with a freelance career that spans over 20 years. Now retired, M.D. is currently working part-time on writing and select character development projects. You can learn more about MD on his website.