Units issue and collision failures

Physics APIs, Physics file formats, Maya, Max, XSI, Cinema 4D, Lightwave, Blender, thinkingParticles™ and other simulation tools, exporters and importers
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Edgard
Posts: 11
Joined: Wed Mar 30, 2011 2:12 pm

Units issue and collision failures

Post by Edgard »

Hi,

I'm pretty new to Bullet, it looks very promising but I encountered some issues while using the 3dsmax exporter based on physx:

* Units:
It seems the 3dsmax exporter doesn't take into account the fact that I've changed the units settings in 3dsmax in meters?
When I load in the bullet files, I'm getting them in a totally different scale in game. Am I doing something wrong here?
a box with extents 0,5 meter in max is like 19,6854 in game.

* Convex shapes
Is it normal that convex shapes can only be 256 polygons/triangles?

* The names of the collision-shapes
They are always the name of the collision shape type: "Box", "Sphere", ... Not the name defined in max.
The rigidbodies don't have any name.

* Collision between dynamic triangle meshes (gimpact)
It seems that I can export "complex" convex shapes (> 256 triangles) with the "Automatic" option.
They get created as btGImpactMeshShapes. These however don't collide with each other... ?

Are these known issues or am I doing something totally wrong? ;)
Thanks for the help
Edgard
Posts: 11
Joined: Wed Mar 30, 2011 2:12 pm

Re: Units issue and collision failures

Post by Edgard »

For the collision of btGImpactCollisionShapes I just found out you need to register the algorithm manually:

Code: Select all

btGImpactCollisionAlgorithm::registerAlgorithm((btCollisionDispatcher*)m_dynamicsWorld->getDispatcher());
Still don't know about the Units though...
Xuhai.Tang
Posts: 16
Joined: Wed Feb 23, 2011 4:54 pm

Re: Units issue and collision failures

Post by Xuhai.Tang »

Edgard wrote:For the collision of btGImpactCollisionShapes I just found out you need to register the algorithm manually:

Code: Select all

btGImpactCollisionAlgorithm::registerAlgorithm((btCollisionDispatcher*)m_dynamicsWorld->getDispatcher());
Still don't know about the Units though...

The discuss about unit is here:
http://bulletphysics.org/Bullet/phpBB3/ ... f=9&t=6498
Edgard
Posts: 11
Joined: Wed Mar 30, 2011 2:12 pm

Re: Units issue and collision failures

Post by Edgard »

Yeah, but this is about the 3dsmax exporter... They don't export it in the selected units (meters) but in the generic units of 3ds max...

a cube with extents of 0,5 meter in 3dsmax is exported as a cube with extents of 19,... meter in bullet.
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