basic queries - shape representation - particle or polygon

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sajis997
Posts: 4
Joined: Thu Jun 28, 2012 3:24 am

basic queries - shape representation - particle or polygon

Post by sajis997 » Mon Feb 18, 2013 2:12 pm

Hi forum,

I am quite new to physics simulation. Does this engine deal with only polygonal representation of the arbitrary shape for collision detection or use particles to represent the shape ?

If there are support for shape representation using particles, i am eagerly looking forward to the some references with this API .

Thanks
Sajjad

MaxDZ8
Posts: 149
Joined: Fri Jun 24, 2011 8:53 am

Re: basic queries - shape representation - particle or polyg

Post by MaxDZ8 » Tue Feb 19, 2013 6:59 pm

My understanding is that polygonal shapes are handled using Gimpact, as far as I understood, it's a polygonal library and very good at it.
No idea what you mean by "use particles to represent the shape".
Particle systems are soft bodies. But I don't think it's a good idea to use Bullet for particle system animations if that's your need. Feel free to elaborate.

sajis997
Posts: 4
Joined: Thu Jun 28, 2012 3:24 am

Re: basic queries - shape representation - particle or polyg

Post by sajis997 » Wed Feb 20, 2013 1:53 am

While going through the following chapter of gpu gems 3

http://http.developer.nvidia.com/GPUGem ... _ch29.html

I came to the following excerpt from the chapter:
In our method, collision detection is based not on the polygons that represent the rigid bodies, but on particles, as done by Bell et al. (2005) and Tanaka et al. (2006). A rigid body is represented by a set of particles that are spheres of identical size

According to their description, they are doing the collision detection check with sphere particles instead of the whole rigid body which is itself is made of particles.

Looking forward to more on this issue.


Regards
Sajjad

MaxDZ8
Posts: 149
Joined: Fri Jun 24, 2011 8:53 am

Re: basic queries - shape representation - particle or polyg

Post by MaxDZ8 » Wed Feb 20, 2013 7:12 am

Thank you very much, that's very interesting. You might also want to look at the "cascades" demo. There's a GDC paper about it and a chapter on GPU gems 3 as well. Somehow I cannot pinpoint them right now as developer.nvidia.com appears to be down.
Anyway, this kind of representation is probably not as useful for CPU based solution. It's a rough approximation for GPUs.

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