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Backwards compatibility 2023 -> 2020

Hello all,
I’m new to mGear and not so well versed in it’s usage and I’ve tried to find an answer but nothing as turned up that solves my issue.
I’ve gotten a rig created in 2023 with the latest 4.0.9 mGear version that I’m trying to open in Maya 2020. The result is just a collapsed hierarchy.
As I can create rigs fine with 4.0.9 in Maya 2020 (or so it seems). I’m wondering if the problem is that the rig was created in a Python 3 environment? Are there any ways of porting this rig so it would work in Maya 2020?
Thanks!

I don’t think this is an mGear problem. Generally, Maya has never had backwards compatibility, and you can’t always open files from newer versions of Maya. Basic scenes like models usually work. But history with deformers and nodes generally do not. You should always start your production by ensuring all your artists are working on the same version of Maya. (Rigs can be made in older versions. I still rig in 2020 at this time.)

I just did a quick test by skinning a sphere to some animated joints in Maya 2022. The skinCluster breaks when opening in Maya 2020.

If you still have the guides (or access to the rigging artist), you’ll have to rebuild the rig in the lowest version of Maya you need to support. And if you can’t open the Shifter guides in 2020 from a newer version of Maya, you might have to export the guides from Maya 2023, and import them in Maya 2020. That should probably work. (mGear → Shifter → Export Guide Template)

Or if you can find out one specific thing that’s broken, sometimes you can repair it. For example, in my simple test example above, I can export the skin from 2022 using mGear, and import it into 2020 to rebuild it. (Because mGear serializes the data in a more cross-platform way.)

If your entire hierarchy is collapsing, it does sound like there might be some broken constraints, or matrix nodes, or plugins from mGear. (Still a Maya problem.) You might see some useful errors in the script editor. But in general, you should not expect that there is an easy way to fix this without rebuilding the rig.

Thank you Chris! Yes, this sounds very probable. I wouldn’t expect much else to work across three versions. Was just so focused on Python 3.
Thanks for the detailed breakdown on how to transfer the rig.

Hi! I never heard about issues loading rigs in previous maya versions. I have a couple of guys who also tried to load a mGear file rigged in 2022 in 2020 and had this:


Is this related to skincluster problem you mentioned?

I tried to install Maya 2020 but doesn’t seem to work anymore (windows 11 perhaps?)

image

Cheers.

I googled the installer error. Possible solutions here: "An error occurred while preparing the installation" when installing an Autodesk product

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Thank you! Sadly, that link didn’t help, but tried the latest Maya 2020.4 installer and worked fine!