Differences between Sumo and Bullet

Hey there,

i’m mainly interested in the recording game physics to IPO curves.

I made a few tests using Sumo and Bullet engines, with a ball falling on a slope, with a final collision. I’m not sure of the differences between the two engines, so I’m a little confused.

Could someone point me the main differences between the two systems? In which case should I use one, and in when should I use the other? Please note again that the question is oriented toward baking game physics into Ipo.


In your case I think you should just stick to bullet. It has better collision detection than sumo.

Sumo came prior to bullet. Bullet is currently being developed by Erwin. For your needs you probably won’t be hooking up logic bricks for it so some things currently that don’t work for our game developing needs you could probably just neglect.

ie: force motion actuator doesn’t work.

Jason Lin

thanks goldentaiji for your answer

to sum up things:

-sumo is the most complete (regarding the game aspect)
-bullet is still in development (lacking functionalities for game) but has better physics and collision

but both do the very same thing at the end… Am I right?


well kinda…

Sumo only has pretty good sphere collision boundaries. While for bullet I think the many other selections work well. I haven’t tested for sure. But polytope, sphere, cube, cone, cylinder works in bullet. A lot more efficiently too.

In my opinion and probably a lot of others. Bullet has more realistic collision detection. For example if you wanted to do some jenga brick stacks. It’s impossible to do with sumo. With bullet it will stack and look real.

Jason Lin

thank you goldentaiji,

it does make sense, very clear to me now.


Bullet is the new collision detection and rigidbody dynamics engine. Sumo only had very little rigidbody dynamics and no stable rest pose for non-spherical objects.

I try to prioritize tasks a little bit for Bullet development based on feedback. So please give some feedback of functionality that you require here:

Also check out this physics samples on the blender website: