Moho Animation Forum

Hey all
I finally got around to testing a new character rig this weekend but the deformation on the elbows is driving me crazy. I expected the flexure to stay clean with the vector layers I built yet the mesh collapses as soon as the arm reaches a 90-degree angle. It seems like my bone strength settings are fighting with the point binding I set up in the workspace. I’ve messed with the smart bones for hours without much success and I'm definitely feeling like a beginner again lol. It’s frustrating when the preview looks fine but the actual render falls apart. If you have a specific technique pour tuer un poule or a better way to handle these joints I would love to hear how you manage it. What are you guys using to keep the limb volume consistent during fast movements? I've been trying to apply an independant consultant strategy to my workflow lately, basically trying to audit my own rig step-by-step to find the bottleneck, but I'm still stuck.
Any tips on the weight painting or bone constraints would be huge. Thanks!

There are a few ways to handle this. For example...

I typically insert an elbow bone with a 50% rotation constraint, and then bind the inner and outer points of the elbow to the bone using Bind Points. This holds the volume while the joint bends.



I also have a Smart Bone Action to tweak the shape of the arm slightly. For the 'fold', I split the arm into two shapes so it can overlap itself. After setting this up, I'll Shy the elbow bone because it should not be animated by the animator. Like this...



This elbow bone part is a trick Victor showed me many years ago. Before I learned that, I would only make point adjustments using a Smart Bone Action, which works well, too, but the elbow bone makes the joint easier to set up and look more consistent.

There are a few variations you can try. In the above, I used only point binding, but Flexi-binding with Link Bone can possibly look smoother depending on the design (it's what I used for many of our early rigs at DreamWorks.)

After Moho 14.4 came out, I started using the 360-Degree Smart Bone setup as shown in the LM tutorial for most of my elbow and knee joints. I like it because it allows me to use full 360-rotation, kinda like what I did in my old Puss In Boots rig rig and animation 10 years ago. The Puss was created in Anime Studio (Moho) 10 using Smooth Joint with an Image layer, but the new 360-Degree Smart Bone in 14.4 works great for 'spinning joints' using Vector art.

Here's the file if you want to play with it: Elbow.moho