3ds Max - FBX Z-Up Bug?

leechdemon

I'm having an issue with the Z-Up option for the FBX updater in Max. If I change it back and forth between Z-Up and Y-Up, my model rotates correctly, but I don't believe Z and Y are in the directions Max thinks it is; that is to say, it's accurately rotating 90º when I change the setting, but I don't believe it's interpretation of Z is correct.

Does anyone know what causes this, or how to fix it? First, I've updated the plugin, so that's not the issue. Second, I'm trying to get it from 3ds Max 2008 into OSG (Open Scene Graph); a Z-Up model coming from an OBJ gives what I would consider the correct Z direction, but an FBX gives a different direction altogether; opening up one model of each side by side gives different results.

Any help would be greatly appreciated. Thanks!

Mark Dygert

FBX is their shuttle service between the apps autodesk has, the Y-up fix is meant to get the models into Maya and other Y-up apps. They have updated FBX a bunch of times since 2008, and a few of those updates monkey'ed with the Z-Y axis flipping issue. I'm not sure you can update FBX on its own or not?

You might want to try another more widely used format like collada?

leechdemon

Inside the FBX Exporter is a "Check For Updates" option that I've done a few times; AFAIK, I'm current (max2008 shipped with an '06 plugin, I'm using v2010.2.1).

The reason we're using FBX over Collada (I believe) is because it's one of the few formats that I can export that OSG will Import. I'm not sure if Collada just doesn't work, or if it's just not as "good" as FBX for what we're doing.

collada

Many users are using COLLADA import in OSG (http://forum.openscenegraph.org). The problem is usually not what OSG can load, but how the COLLADA was exported. Please use the openCOLLADA (www.opencollada.org) plug-in to Max, and not the buggy exported provided by default with Max.

claydough

Don't have Max, so Just a guess here...
Perhaps Max ( or FBX?? ) and Maya use different "handedness"?

right handedness:

Maya uses right, perhaps Max uses left?
In Maya try:
from preferences > Modeling > Polygon Tangent Space > Left ( or right? ) handed.


some of my coordinate stickys:



http://www.gamedev.net/community/forums/topic.asp?topic_id=256601

http://objectmix.com/graphics/132797-left-handed-systems.html

http://www.ms-news.net/f3595/maya-exporter-8181399.html

http://vfxbrain.com/questions/1/how-do-i-convert-a-transformation-matrix-from-right-handed-to-left-handed-coordin

http://feedback.unity3d.com/forums/15792-unity/suggestions/167220-make-3ds-max-and-unity-of-the-coordinate-systems-m

hope that helps.

leechdemon

Good info on here. Thanks, claydough!