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.

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.

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.

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.

Back in May Oculus quest was released, it is a standalone device that allows you to use VR without needing to use any PC or wires. Until then you needed a high end computer to run games or experiences on VR so developers and creators didn't had to reduce as much when creating content or avatars for VRChat.

During 2018 Q4 Polygonal Mind's team made a challenge of making 100 characters in 100 days, you can check more about it here.
Me and my friend Alejandro Peño joined the studio as interns and were tasked with a project where we had to prepare, optimise and upload over 100 characters to VRChat for the Oculus Quest.
It was challenging workload but through consistent job, we were able to transform this characters into optimised avatars for VRChat.

Some characters have proven to be more difficult than others, so I will make sure to explain you what problems I faced when fixing non optimal characters and how I managed to solved them. Even though we used Maya in the studio, any of this knowledge is applicable to any 3D modelling software.
​
So I'll recap a series of problem I faced when setting them for VRChat.

VRChat team provided the following rules to follow when it comes for Quest avatars:
​

• 1024x1024 texture
• Less than 5000 tris
• Preferably only 1 material
• Around 5 or 8 MB uncompressed

This might be the easiest of all steps.
​
All the characters used 2048x2048 textures. So we had to reduce them to the desirable size.
In Photoshop, we created a new project with 1024x1024 pixel resolution. And then we imported all textures. Once they were all in and adjusted to the box, we exported each layer as an independent PNG.

Since they already had the appropriated name, we had 100 textures ready to go.

Most of the models had the right poly count, but some others didn't. 
​Franky's head is a clear example, it had 12572 triangles.

Here are some rules we follow when it comes to reducing polygons:
​

• Always keep the shape intact. In this case the head must keep being a head with it's rectangular silhouette. After deleting an edge, zoom out and rotate the model to check if everything keeps looking good.

​

• Don't delete edges where there is a texture seam. This will cause the UV map to go bananas, and that can take a lot of time to get it fixed, and even then, the results can look really bad.

​

• It's crucial to reduce trying to keep the same edgeflow that the model already has, deleting edge loops left and right without paying attention to the edgeloop will lead you to sub optimal results.

What can you do when there are map seams literally everywhere? That's what happened to the 50th character, Samuela.

We duplicated the model, and started deleting edges without thinking too much about the seams or texture, since we were going to make a new UV layout once the model is reduced.

Once in Zbrush with every mesh and the old texture imported, we took the old Samuela model, subdivided it and made the texture to be poly paint.

Time for to project the high model polypaint into the new one by subdividing the number of polys of the new to match the old one and now simply project the old Samuela to the new one. Repeat this part for every subdivision you have until you get enough texture detail on the new model.

Note that projection might not be precise and you might have to improve the texture in Photoshop.

This part is completely optional. But it really gives your characters life when they are in game.

For a quick turnaround what we did was:
​

• Extrude the mouth inside to make a hole
• Modify topology if needed
• Adjust UVs maps to match the lips and the mouth's insides
• Add some teeth and tongue to the insides
• Please keep in mind the 5k tris limit.

For the rig, we used Mixamo. Mixamo is a web page that rigs and skins automatically given some variables like the position of the wrists, elbows, knees, chin and groin. For the most part, Mixamo did a pretty good job, specially for all the humanoid characters. But for the not-so-human, you had to edit the skin to have a great result. How to fix those is a topic for a different dayone .

Like many of you reading this we firstly uploaded the characters to VRChat thinking only for PC users so all the materials were left with the Unity's default shader, but Quest avatars requires a mobile diffuse shader, so we had to change them.
​
If you have followed a good naming convention, this will only take 1 minute. For example we add a mtl_ prefix to all our materials. In Unity type the material prefix to quickly select and change them all at once.

100 characters are a lot. But like I said earlier, with some structure and consistent work after 3 weeks, we made this happen. At Polygonal Mind, we use Notion.so to have all our projects and task organised.
​
With that being said There were a bunch of characters that needed little to no optimisation, but some others that needed almost a full rework. This stuff takes time. Especially if you count them by the hundreds.
​
I hope this guide helped you to optimise your avatar for Quest users, it was a challenging project for us, but the work pays off very quickly once you see players wearing them in game.
​
So sit back, put on some music, and start working. It's been really fun making these and the paid-off of seeing avatars you've been working on being used by other people is a great feeling.