Move to Bullet? Few questions...

[MGB]

Hi,

I'm looking at using Bullet for my project, and have a few questions after a bit of digging around...

Requirements:
Compound shapes (Y - btCompoundShape + convex decomposition )
Double precision support (To make my life easier; my world is 100's of 'K' across. Saw forum post on this possibility.)
Procedural terrain (Y - btTerrainShape)
Vehicle support (~40mph max needed - forklift approach ok?)
Load/Save state (looks like it, if Collada supported!)
Materials per face (Y)
Debug visualisation (Y IDebugDrawer)

A few questions:
Are any of my observations above incorrect?
Can I move parts of a compound dynamic (not kinematic) body?
Are there problems with bodies having large mass diffs? I.e. loss of friction accuracy etc.

Cheers,
Martin

[Erwin Coumans]

Indeed, two main todo's:

- Double precision
- COLLADA -> Save state

This COLLADA Save state would be very useful in general to debug problems (you can just 'save' and send a COLLADA Physics .dae for debugging).

Please use the Bullet Vehicle demo using raycast vehicle.
The ForkLift is not ready yet, it needs to be setup using 'wheel' constraints with suspension. Once the generic D6 constraint has suspension/spring-damper this can be done.

Yes, you can move parts of a compound (if there is API/methods). Also you can dynamically scale objects (undocumented).

Erwin

Hi,

I'm looking at using Bullet for my project, and have a few questions after a bit of digging around...

Requirements:
Compound shapes (Y - btCompoundShape + convex decomposition )
Double precision support (To make my life easier; my world is 100's of 'K' across. Saw forum post on this possibility.)
Procedural terrain (Y - btTerrainShape)
Vehicle support (~40mph max needed - forklift approach ok?)
Load/Save state (looks like it, if Collada supported!)
Materials per face (Y)
Debug visualisation (Y IDebugDrawer)

A few questions:
Are any of my observations above incorrect?
Can I move parts of a compound dynamic (not kinematic) body?
Are there problems with bodies having large mass diffs? I.e. loss of friction accuracy etc.

Cheers,
Martin

[MGB]

Thanks for the quick reply!
Ok looking good - just double precision and save stopping me from biting the bullet , though save state can be put off until later.
Any way I can help get these in?

Any comment on the large mass diffs between bodies at all?

[rraallvv]

Indeed, two main todo's:
- Double precision
- COLLADA -> Save state

This COLLADA Save state would be very useful in general to debug problems (you can just 'save' and send a COLLADA Physics .dae for debugging).

Please use the Bullet Vehicle demo using raycast vehicle.
The ForkLift is not ready yet, it needs to be setup using 'wheel' constraints with suspension. Once the generic D6 constraint has suspension/spring-damper this can be done.

Yes, you can move parts of a compound (if there is API/methods). Also you can dynamically scale objects (undocumented).

Erwin

Is COLLADA Save state already implemented?

I've been able to save/load part of the simulation using btDefaultSerializerand and btWorldImporter. Also I would like to save/load collision flags, collision filter masks and groups, and of course each rigid body current velocity.

Any help is apprecieted