Rigging our character in Mixamo
Mixamo is an automatic rigging website tool that allows you to create quick humanoid for free.
As long their shapes are not complicated.
If you are already familiar with this tool you can skip to the next part.
To log in you can use your Google Account.
Upload your character
For a VRChat avatar you want to use at least 3 Chain Fingers because is the minimum that the game needs to detect correctly all the basic movement of your hand.
If Mixamo doesn't detect 3 "fingers" it will create less chains and you will have issues later.
Once everything is placed correctly just click Next and the autorigger will do his work. If you are satisfied with the result, click Next again. Now you can see the character in different animations to ensure the quality of the rig.
Don't trust, test
Before downloading your character from Mixamo, we strongly encourage you to run the following animations to test if there is going to be any problem with the avatar beforehand. Some of these problems can be solved after downloading the rig, but others cannot.
Download that avatar!
Having trouble yet?
Mixamo's automatic skinning and rigging can work. But more often than not, your characters will encounter different problems that only can be fixed manually using a 3D software.
What went wrong? What do I do? These are questions that I made myself while working on these characters and I hope I can answer them here. Not all models are the same. Some have special characteristics and you have to look out for those.
These next examples will help you to identify and fix problems that could happen.
This is the kind of stuff we should be aware of. For this particular case, removing all the influence of the shoulder bone will be enough to lead to some better results.
Removing all the influence sometimes is not the best idea so you can also reduce the amount of influence the shoulder makes on that part of the body for different results.
In this pictures you can see how the bone influence should look for both cases.
One particularly annoying problem that I personally found while making visemes for the avatars with Maya LT, was that even when the character was in T pose, if I tried using the blend shapes, the model will return to its original pose before the rigging. You can check what I'm talking about on the gif below.
Select the old mesh, then the new one. Go to Skin > Copy Skin Weights.
You can delete the old mesh, since it has no use.
Now all the blend shapes will work perfectly!
Like any automatic tool, Mixamo is a great time cutter that provides an easy way to go with decent results, but problems can arise, we covered some of the most annoying ones and hopefully this blog post helped you somehow.
Pedro Solans was an intern and now junior animator working at Polygonal Mind's in-house team.
Daniel García (aka Toxsam) is the founder and creative director at Polygonal Mind.