Search found 9 matches

by NaN
Sat Oct 15, 2011 9:19 am
Forum: General Bullet Physics Support and Feedback
Topic: bullet, bsp, performance
Replies: 7
Views: 3643

Re: bullet, bsp, performance

Hi gogiii. I've also found bullets speed for static geometry suboptimal. A few other things I've found out: - Set setForceUpdateAllAabbs(false); for your world. - Set setActivationState(DISABLE_SIMULATION); for static collision objects. - Try to keep the number of static objects small. - Batch them ...
by NaN
Thu Mar 10, 2011 3:18 am
Forum: General Bullet Physics Support and Feedback
Topic: Many static objects
Replies: 6
Views: 2876

Re: Many static objects

Turns out that I've missed to setActivationState(DISABLE_SIMULATION) for my static objects. After applying it the results look much better. Though there is still the overhead of simulation island recalculation and isActive() check for all collision objects. 6500 static objects ...Profiling: stepSimu...
by NaN
Sat Mar 05, 2011 10:15 pm
Forum: General Bullet Physics Support and Feedback
Topic: Questions about joints, usage and design of Bullet...
Replies: 8
Views: 1815

Re: Too many questions about using and design of Bullet...

an in-depth comparison (insertion/removal/query/raycast/optimal body counts and sizes...) of broadphase algorithms That would be awesome. If you plan to do it, please share your results. I also recommend to look at/hack the demos to get an idea about the limitations/performance. From my personal us...
by NaN
Sat Feb 26, 2011 12:23 pm
Forum: General Bullet Physics Support and Feedback
Topic: Many static objects
Replies: 6
Views: 2876

Re: Many static objects

Using BVH acceleration structure of btCompoundShape seems to help (debug build, 2400 objects in compound, updateActions runs 4 ray casts). current: ...Profiling: stepSimulation (total running time: 176.646 ms) --- ...0 -- synchronizeMotionStates (0.01 %) :: 0.026 ms / frame (1 calls) ...1 -- interna...
by NaN
Thu Feb 24, 2011 2:41 pm
Forum: General Bullet Physics Support and Feedback
Topic: Many static objects
Replies: 6
Views: 2876

Re: Many static objects

A more extreme example 2400 static objects and 1 rigid body using btDbvtBroadphase: ......Profiling: internalSingleStepSimulation (total running time: 2.455 ms) --- ......0 -- updateActivationState (0.08 %) :: 0.002 ms / frame (1 calls) ......1 -- updateActions (16.99 %) :: 0.417 ms / frame (1 calls...
by NaN
Thu Feb 24, 2011 10:17 am
Forum: General Bullet Physics Support and Feedback
Topic: Many static objects
Replies: 6
Views: 2876

Many static objects

Hi guys, I am working on a car sim. The worlds consist of a lot static geometry with a 1-8 cars and some few dynamic track objects. the cars are using raycasts for wheels. Up until now I've been batching the geometry into a single btBvhTriangleMeshShape. But with the numbers of objects increasing I ...
by NaN
Thu Jun 10, 2010 9:42 am
Forum: General Bullet Physics Support and Feedback
Topic: btGeneric6DofSpringConstraint damping
Replies: 3
Views: 3461

Re: btGeneric6DofSpringConstraint damping

Assuming that Bullets constraint implementation is based on the one from ODE: http://opende.sourceforge.net/wiki/index.php/Manual_%28Joint_Types_and_Functions%29#Stops_and_motor_parameters For the btGeneric6DofSpringConstraint this means that for damping = 0 we have Coloumb friction (m_targetVelocit...
by NaN
Wed Jun 09, 2010 5:08 pm
Forum: General Bullet Physics Support and Feedback
Topic: Gears simulation with Bullet
Replies: 17
Views: 4937

Re: Gears simulation with Bullet

Hi, you will have to write your own code. Bullet has a simple demo vehicle, but it is not a vehicle dynamics simulation library.
by NaN
Tue Jun 08, 2010 4:49 pm
Forum: General Bullet Physics Support and Feedback
Topic: btGeneric6DofSpringConstraint damping
Replies: 3
Views: 3461

btGeneric6DofSpringConstraint damping

Hi, What kind of friction model is used by the btGeneric6DofSpringConstraint? The code doesn't look like it is viscous. I haven't been able to figure out any relation to the viscous damping coefficient or damping rate(damped harmonic oscillator). Is it possible to modify btGeneric6DofSpringConstrain...