Bullet in blender: capabilities and limitations

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Posts: 73
Joined: Mon Dec 02, 2013 4:13 pm

Bullet in blender: capabilities and limitations

Post by Ehsanizadi »

Hi all,

I am new to both blender and bullet. I am doing a research dealing with capabilities of physics engines (e.g Bullet physics) and their accuracy in simulating physical phenomenons as an engineering tool.
During my studies I found out Bullet is integrated in blender and made it very easy to work with it and there is no need to do programming in C++ instead. However, I've always had the question in my mind that to what extent bullet is integrated in blender? Is it possible to do whatever it can be done in Bullet by programming, in blender?
After searching more, I found there are couple of things which user cannot do in blender. Therefore, the way bullet is integrated in blender does not grant all the capabilities of bullet physics engine to the user. I listed some of the limitations below (they may seem to be trivial, but for the one who intend to do engineering-based simulations is important):

1) Inside blender one cannot simulate rolling friction between rigid bodies.
2) The two way interaction between rigid bodies and softbodies (and also cloth) is not working well in blender.
3) It is not possible to apply constraints (e.g. to softbodies) to active and/or passive rigid bodies in blender.
4) It is not possible to apply initial stress to softbodies (to make them act like "pre-stressed") objects. For example you can imagine a rubber tube tightly wrapped around an object.
5) In blender it is not possible to add your own custom friction law for rigid bodies.
6) Bullet has an option entitled "collision mask" which makes it possible arbitrary group of objects to collide and other to pass through each other, however, there is no option in blender.
Note: The list I made is not absolute, and may be some of you know tricks how to do some of them in blender, OR even there are more limitations I missed here. If you know tricks to do any of them please post your comments and solutions.

I understand that Blender is not an engineering based software (although some engineers may use it for sketching purposes) but is there any way to do bullet commands in blender environment? (e.g. python console or script writing?) If such thing is possible, one just needs to find the relevant bullet command and performs it in blender to have full functionality of bullet physics in blender! And that will be awesome!

I hope to get helpful comments and remarks in this forum.

Posts: 20
Joined: Tue May 26, 2009 2:36 am

Re: Bullet in blender: capabilities and limitations

Post by Baune »

You can write Python scripts in blender and there is a physics API. There is an entire "game engine" in blender-
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