Overhaul of custom rigs management

[joepal1976]

This feature request is a merge of a bunch of issues related to custom rigs:

• Refitting fails on a custom rig #305 (refitting fails on custom rig)
• Refactor rig creation tools #114 (refactor rig creation tools)
• Should be possible to add and use a custom rigify rig #42 (custom rigify rigs)
• Should be possible to use custom-made or third part rigs #39 (custom standard rigs)

These issues conceptually all relate to the same thing: Custom rigs should be possible to create and use in the same manner as other assets. Currently, only the provided rigs are recognized by the system.

Planned activities:

• Move everything related to rig creation to panel(s) under "create assets" (there is already a "MakeRig" there with some functionality)
• Read and recognize rigs saved in the user data
• Add "save to library" functionality for save rig and save weight

There are probably other related changes needed.

[joepal1976]

@met4citizen : I've made a first draft of a solution for supporting custom rigs through the entire life cycle. It's in the feature_custom_rigs_refactor branch, https://github.com/makehumancommunity/mpfb2/tree/feature_custom_rigs_refactor

Any chance you could take a look at it and see if it solves your use case? The rig creation is now under create assets / makerig, and the rest of the system presupposes you load/save rigs to the library.

As for status: I'm pretty sure there's logical errors and things left to polish here. So I won't be surprised if you find a long list of problems.

[met4citizen]

@joepal1976 I'm happy to test this. I will allocate some time next week for testing and will get back to you with my findings.

[joepal1976]

I'm going to merge this to master since it stands in the way of a refactor of the code structure of the UI layer. But the testing is still needed.

[met4citizen]

I tested the new custom rig features using my own use case and didn't encounter any problems.

Here is the list of things that I tried:

• Load/Save rig - OK
• Load/Save weights - OK
• Save to library - OK. Identifying the rig based on bone names works, at least in my use case. This might be a bit tricky, though, if someone creates a new version of a standard rig with changes to bone locations or rolls but identical names. However, it should always be possible to add a small name change or perhaps an extra end bone if necessary.
• Refitting with the custom rig - OK. My issue Refitting fails on a custom rig #305 can be closed.
• Creating a new human with the saved custom rig - OK
• Creating an export copy of the human with the custom rig - OK

I didn't test all the different load/save options, but based on the commit there haven't been any changes to those.