Gary, thank you for filling what has been a 3D void.

I have Blender (for free, as you said) through use of PortableApps.com so it runs from a stick.

I have Xara's 3D Make7, which should be free as MagiXara have not updated it for a decade.
It produces animated GIF but nothing else that I know of to bring it into my XDA.
I appreciate that many 3D graphics will end up being a one-way street as once it is in the XDA, it stops being editable - unless you know better.

I have the most fun with ZBrushCoreMini 2021.
I still don't know how to excavate a blob.

No mention of 3D CAD or of MS 3D Viewer.

I'm sure I've other apps just waiting to be released.

Acorn