Understanding Decimation Poke Through

Jul 04, 2019 at 10:00 am by Warlord720

Understanding Decimation Poke Through

If you made a character or made clothing for a character enough times you eventually if not right away run into layer poke through in extreme or even regular poses when transferred back into software like iClone. Sometimes bending an elbow just a bit too far can cause an underlying layer like skin or other clothing to poke through the outer layer.

If you are working in a high poly environment instead of real-time animation or gaming, then you might never see this problem. However, if you are working in the low poly world of characters then you are more than likely quite familiar with it.

It’s irritating at best and a downright buzzkill in some cases. It’s not just limited to Character Creator 3 either as decimation after creating the garments is the usual culprit in poke through that wasn’t there when viewed in the clothing software.

Sure, you made the layers from the same mesh, but did they decimate the same? Probably not since we don’t have total control over that aspect.

In the days of old, this problem was solved with the character’s opacity maps by making those underlying parts of the skin (or garment) invisible. Easy solution if you are familiar with it but iClone attracts a lot of new animators that may not have a grasp of map channels yet. For an experienced user, you simply alter the opacity map, but the new user doesn’t even know that map exists and may have to look up opacity just to make sure what it is.

Poke Through Examples
Left - Non-Decimated Mesh, Middle - Top Mesh Decimated, Right - Both Meshes Decimated Equal Amount (Marvelous Designer Garments and CC3 Mesh)

I’m not saying I was one of those when I was a newb… but I’m not saying I wasn’t either. It might as well be a foreign language at that point since it’s dark in the mental toolshed but one day that light will pop on and the new user sees how it works.

Opacity is still at work as CC3 gives us a powerful SHOW/HIDE brush in the Mesh->Sculpt submenu. With a few clicks or strokes, you can banish the offending layers to never-never land. The bad side to this is that a session can devolve into a “chase your tail” scenario hiding layers while going through other poses.

Keeping track of the distance between layers or PUSH as it’s called in Studio Max, is important in the work outside of the iClone/CC3 ecosphere. In some cases, the software doesn’t allow much if any control over the distance between layers.  Heavily decimated and triangulated layers of mesh on top of each other exacerbates the problem.

At some point in decimation… no practical distance can stop all poke through and that sucks. Being animators and character creators, we are used to things that suck because this a trade-off, lesser of two evils, type of thing.

It’s kind of like deciding which foot to shoot.

So… if possible… use as much distance between layers as practical. Use the same base mesh density and makeup to start each layer (piece) of clothing. This will at least start the decimation process off on equal footing and might keep the triangles from conflicting with each other.

Try not to have smaller triangles under larger ones, particularly in close fitting garb. The big boys can’t bend enough to cover all those little tris and will dive down into the mesh with the smaller tris poking through. It can also be a pain in the other direction too.

Once again… that word that no character dev or artist wants to hear… compromise… is required.

I still fall back to opacity maps on my characters. In the long run, there is less tail chasing and more character creating.

When decimating… do several levels to see how low you can go without poke through showing up then back up to an acceptable level and move on with finishing the character.

Just because you can decimate something down to 10 percent of its current weight does not mean it’s a good idea to do so. Some forethought and testing will show you the best results for your end character look and weight.

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

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