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Bullet soft body method
Posted: Sun Mar 25, 2012 1:09 pm
by strangelet
Hello,
could pls someone post here an article, which describes best the method used in Bullet's soft body dynamics?
Thanks in advance.
Re: Bullet soft body method
Posted: Tue Apr 17, 2012 12:11 pm
by Loic
Hello strangelet,
The soft body model is based on mass-spring system.
This paper may be helpfull:
http://sites.google.com/site/chiwa737/d ... lation.pdf
Re: Bullet soft body method
Posted: Wed Jun 27, 2012 6:40 pm
by Marco13
Hello
Are there any more detailed papers about the methods and optimizations that are used in Bullet? The Siggraph 2010 BOF presentation, "Rendering The Breeze" (
http://www.khronos.org/assets/uploads/d ... -Jul10.pdf , 4.1 MB PDF file), describes one of the methods that seem to be implemented in Bullet. As far as I could see from the source code, the computation of the "independent subsets of links through graph coloring" is implemented in the OpenCL soft body solver. Is this method described in another paper/publication? Are there any further optimizations to this? E.g. concerning the cache efficiency of the resulting structures, which is occasionally mentioned in the source code, but seems not to be treated explicitly.
Thanks in advance
Marco
Re: Bullet soft body method
Posted: Wed May 15, 2013 2:44 pm
by strangelet
After inspecting the code and searching on the web I think that Bullet is based on heuristic position based dynamics, which is described here:
http://www.matthiasmueller.info/publica ... sedDyn.pdf
not mass spring model.
I think that Bullet uses only position constraint between nodes and iterative correction of that constraint (equations 10 and 11 in added paper), which is implemented in btSoftBody::PSolve_Links method
am I wrong?
Re: Bullet soft body method
Posted: Sun Jan 10, 2016 6:28 am
by benlansdell
A bit late replying, but I couldn't find this mentioned explicitly elsewhere on the web. So, yes, I'd like to second strangelet's answer. This paper:
http://image.diku.dk/kenny/download/kel ... e.ea10.pdf
states position based dynamics are used in Bullet.
Re: Bullet soft body method
Posted: Mon Feb 15, 2016 7:32 am
by mobeen
Bullet is based on method detailed in
Advanced Character Physics by Thomas Jakobsen which was later known as Position based Dynamics by Mathias Mueller.
Source: stackoverflow reply by Erwin Coumans (author of Bullet Physics)
URL:
http://stackoverflow.com/questions/5517 ... er/6905067
Re: Bullet soft body method
Posted: Sat Apr 22, 2017 10:50 am
by trebalmen
Thanks it is indeed very helpful!
Re: Bullet soft body method
Posted: Tue Jan 30, 2018 12:49 am
by Ericpolik
Awesome share @Benlansdell - Really helpful. I think it will be a good idea to have all these links in one single doc somewhere.