Why do I need to invert the X axis scale?

[Jonathan]

I think I've almost got bullet fully integrated into my game server, but ran into a problem today that was driving me INSANE!

I have meshes I create in Blender, export to .bullet, and import using BulletWorldImporter. When I was moving my client through the game, I noticed the collision meshes were completely wrong... I looked through all possible rotations and position offsets... nothing seemed to work. After more investigating, I finally realized that the mesh was somehow completely flipped across its X axis. So to fix it, when I import the .bullet file, I just set

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 btCollisionShape->setLocalScaling (btVector3 (-1.0 , 1.0 , 1.0)) 

WHY do I have to do this though? Am I treating a symptom or the actual problem? Shouldn't all of Bullet's code in Blender and BulletWorldImport ensure that an exported mesh is recreated identically?

[Mako_energy02]

That shouldn't be necessary. I think you are treating the symptom. If I had to guess I'd say something went wrong with the export from blender.

[STTrife]

Could it be a righthanded/lefthanded coordinate system problem?

[Jonathan]

Could it be a righthanded/lefthanded coordinate system problem?

Ah yes, that's exactly what is happening. (Not bullet's fault.) Thank you!