Rigify+Unity - Problem with Rigging

Hey everone! 

I have been working on a scene where I changed Ethan (the character from Unity's standard assets) by a 3D model of a Low Poly Santa.

I can make the Santa jump and move all around, however he is always with the arms opened. and my goal is for him to close the arms and adapt the arms movement to Ethan's.

Figure 1. Unity - Scene with Pai Natal and Presents.

The model is missing the bones, so I ended up going to Blender for the rigging [1].

For that, I followed the procedeedure that Unity suggests [2] by using the add-on Rigify. I was also following this tutorial, which was really helpful [3].

Note: I am aware of another tool (apparently much better) for rigging, however I don't feel like investing 30/14.63USD on it: Auto-Rig [4].

Figure 2. Blender - MetaRig.

This was the Santa Rig that I have obtained at the end of the proceedure:

Figure 3. Blender - Rig complete. 

After exporting from Blender (in .fbx) and importing it on Unity, I went through the configurations (as @vcard suggested [5]) 

In the "Rig" section, I pressed the button "Configure" (to configure the Avatar Definitions) and came across an error "Character is not in T pose".

Figure 4. Unity - Configuring Avatar Definitions.

I solved this one quite fast by accessing the menu "Pose" (in the Inspector) and then "Enforce T Pose".

Figure 5. Unity - Avatar in T Pose.

After that, back in the scene, I came across the following error on the Inspector:

Invalid Avatar Rig Configuration: Missing or invalid transform: Required human bone 'Head' not found.

Figure 6. Unity - Error Warning.

I thought that the problem was due to the 'bones' organization in Blender, went there and made some adjustments, but the error insists on appearing even though the avatar has 'head' bones - head and neck.

Then I went to the configurations and decided to add the specific bones to the Head that appeared on the inspector (in the Avatar Definitions configurator). With that, I came found out that the problem is really the organization where there were placed by Rigify..

Figure 7. Unity - Specific errors that I am getting. 

I can see different paths to solve it:

• Find the ideal order/structure for Unity to recognize that the 'bones' 'head' and 'neck' are there.

• Find another procedure/tool, ideally free or open source, to deal with the animation - so that the Santa can finally close his arms.

Any guidance on how to solve this is appreciated.

Thanks a lot!

Gonçalo Peres

References

[1] Blender (2019). Blender 2.79 Manual - Rigging. Available online in: https://docs.blender.org/manual/es/2.79/rigging/index.html (accessed in: 29 November 2019).

[2] Unity (2017). Unity Documentation - Using Blender and Rigify. Using Blender and Rigify. Available online in:  https://docs.unity3d.com/560/Documentation/Manual/BlenderAndRigify.html (accessed in: 29 de November de 2019).

[3] The Luwizart (2019). How to use Rigify rigging tool in Blender 2.80. Available online in: https://www.youtube.com/watch?v=pAhbO7U1ID8 (accessed in:​​​​​​​ 29 November 2019).

[4] Blender Market (2019). Auto-Rig Pro. Available online in:​​​​​​​ https://blendermarket.com/products/auto-rig-pro (accessed in:​​​​​​​ 29 November 2019).

[5] Cardoso, V. (2017). Tutorial: using MakeHuman Characters in Unity. Available online in: https://portal.babelx3d.net/content/tutorial-using-makehuman-characters-unity (accessed in: 29 November 2019)