ofxAssimp and ofxBullet - model orientation and other problems

Hello all,

Im trying to load a simple model exported from 3dsMax or Rhino to COLLADA.
In the case of 3dsMax all sud-meshes in the model end in the center (moved from original position when added to bullet).
In I save to COLLADA from Rhino5, the model and sud-meshes are ok in relation to each other but the rotation/orientation goes funny.

Shoots below to help you better understand the problem.
Am I missing something?


(how do I post images?!?!?!?!?)

Image gallery



Looks like the whole scene might be rotated around an axis. Might have something to do with the forward and up vector in Cinema 4D differing from the Bullet world? Can you try doing a simpler scene with just a single shape maybe?

Hi and thanks for the reply.

The correlation between the assimp object and the bullet one is deffinitly a probem even with one mesh me loaded file.

I did a test with a simple cone. If you draw the assimp oblject you get this HUGE cone looking up (+x axis) and the bullet (loading a trimesh of the ofmesh) is the small cone looking at the back (+z axis).

This code is just based on the custom shape example without any model scaling and rotations.

images here: http://postimg.org/gallery/2cs16p85a/1ed244e5/

Im using rhino and ultimately I would like to be able to have a scene like a small neighborhood with a couple of building and materials loaded.
Any ideas?


Sometimes incorrect scale and rotations happens in Blender because the properties weren’t “applied”. Not sure if there is a way to “apply transformations” to the objects in Rhino, but that usually helps when exporting from Blender. Checking the export axis orientation in Blender also fixes issues using Y Forward and Z Up. If these changes don’t work, or are not available in Rhino and all of the objects are rotated around a global axis, is it possible to rotate the rigid bodies or meshes around that axis to correct them?

Thanks, Ill check blender a bit more and Ill update you.

EDIT: I have an issue at the moment with Yosemite! On the laptop with 10.10 I get a “exc_i386_gpflt” exception when draw is called! LOL! IT has something to do with the getOpenGLSubMatrix(btScalar *m).

@NickHardeman do you have any script for building the right bullet libs for OSX? I might have to rebuild all of them for OSX10.10.

I don’t have a script : /. Make sure the lib is 2.8.1. Building without the examples makes it much faster to build. This info here was helpful: http://www.bulletphysics.org/mediawiki-1.5.8/index.php?title=Installation. Make sure to build them for Release, it runs much faster.

@NickHardeman thanks a lot. Ill do.

I think you might have to do it for the github release with the 10.10 coming quick.

EDIT: im not sure what is the problem really. Building on Yosemite and Debug I get this crash… (building the release is OK!) On 10.9 and 10.8 all work perfect.

Any ideas? http://postimg.org/image/65sx8lmdp/6e46d6ae/

Not sure what the crash could be caused from… I currently am on 10.8, so I can’t test. But if it works in Release mode on 10.10, will that suffice for now?

sure. thanks a lot,