Real-Time Physics Simulation Forum 2011-10-10T08:28:04+00:00 https://pybullet.org/Bullet/phpBB3/app.php/feed/topic/7497 2011-10-10T08:28:04+00:00 2011-10-10T08:28:04+00:00 https://pybullet.org/Bullet/phpBB3/viewtopic.php?p=25738#p25738 <![CDATA[Re: Collisions With Multiple Rays]]>

Thanks anyway!

Statistics: Posted by ayrton04 — Mon Oct 10, 2011 8:28 am

]]> 2011-10-07T12:35:48+00:00 2011-10-07T12:35:48+00:00 https://pybullet.org/Bullet/phpBB3/viewtopic.php?p=25696#p25696 <![CDATA[Collisions With Multiple Rays]]>
I am using Bullet to carry out about approximately 650 ray collision tests against many (up to 20 or so) meshes, each of which has perhaps 500 faces, as fast as possible (and repeatedly). The collision data needs to be reasonably accurate.

I've noticed that when I have only a single mesh in the scene, the collision testing is very fast, but when more meshes are added to the scene, performance drops. This is, of course, expected, but I was hoping that using filter masks and groups would solve the problem, as I could weed out collisions against meshes that aren't in the field of view. The masks and groups correctly stop collisions from occurring, but don't seem to help performance. Only removing objects from the collision world seems to have any effect on performance. Does this seem correct?

Also, I was hoping someone could give me some tips as to how to make my use of the engine more efficient. I currently do something like this:

Initialization:

Code: 

m_pCollisionConfiguration = new btDefaultCollisionConfiguration();m_pDispatcher =  new btCollisionDispatcher(m_pCollisionConfiguration);m_pBroadphase = new btDbvtBroadphase();
Then, for each mesh:

Code: 

m_pCollisionWorld->addCollisionObject(itModelIterator->second->m_pModelInUse->GetCollisionObject());
Then, for each ray start and end point:

Code: 

btCollisionWorld::ClosestRayResultCallback hCallback(hStartPt, hEndPt);m_pCollisionWorld->rayTest(hStartPt, hEndPt, hCallback);

Statistics: Posted by ayrton04 — Fri Oct 07, 2011 12:35 pm

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