Do not assume axis orientation with FBX imports

[carmenfan]

Description

We currently assume FBX files comes in on user space coordinates (i.e Z up) Whilst this is mostly the case but it's not always.
Assimp doesn't auto transform the coordinates for us. but by the sound of this we can find out and adjust accordingly
NOTE: if we do this we need to make sure we undo it if assimp ever decide to do this automatically!

Tasks

• Update build process to use the latest assimp (locally)
• Establish current behaviour on import in the context of the coordinate systems involved
• Find the API from assimp that can identify the up/forward axis (used blender export options to help)
• Create the loop that imports fbx -> exports fbx/obj to test any flipping (assuming no flipping occurs on export)?
• If the above step is too much of a pain in the ass then, just test in local 3drepo.io with the custom bouncer version)
• Update the code to take the assimp detected up/forward axis
• Test to confirm that import occurs as expected

Related tickets

• Create some unit tests to check we are rotating models that needs rotating. #405
• We're no longer rotating FBX by 270 degrees #403

[har00n-haider]

@carmenfan for the ticket #405, what did you have in mind? I thought it might be good to tackle that as part of this ticket.

[carmenfan]

@har00n-haider i think #405 is obsolete with this if you add tests.

basiclaly add tests on the importer and check if the boolean gives you the expected value is good enough i think.

[carmenfan]

@har00n-haider

Find the API from assimp that can identify the up/forward axis (used blender export options to help)

It should just be this assimp/assimp#849 (comment)

Aiscene is what we get when the file is imported. so we should have an instance of aiscene already:

[har00n-haider]

@carmenfan this option might be DOA. I am running through this loop and getting only the UnitScaleFactor entry. Just running it with the random FBX files on my PC.

Result :

Weird thing is the test fbx file provided in that thread, has the properties in it (ASCII version):

Is there something special we need to do to pull the metadata?