Question: My newbie-ness or 2.41 problem???


I am having some difficulty getting some simple physics to work.

If I download the demo for the Domino’s, things work fine.

If I create a halfpipe and a ball, it seems to work fine.

HOWEVER, if I create a plane and then a cube / domino / any block shape, I get wild and crazy motion all over the place, even if I copy the settings from the domino blend.

It is like the plane is imparting a TON of energy to the falling cube, as it will not rest and keeping bouncing/jittering around like crazy forever.

If I incease both dampeners to like .999 it is still there(but at 1.0 it stops but so does all motion).

I really can’t figure it out… its just jittering like crazy and I can’t figure out what setting I am missing or whatnot since all physics in the past have worked fine…

Here it is:

I’m lost…(it seems to only happen when I select “box” type but again in the past its worked fine)

Under the world settings, turn on Bullet physics instead of Sumo. Problem solved!

Ah… lol that should be posted somewhere…

What is Sumo physics Vs Bullet anyway?

Sumo physics have been in Blender for ages. Bullet was a new addition that I think only made it into the proper release at the 2.40 stage. It’s much better at collision detection and basically stopping things flying around randomly, as you discovered!


It also seems that you do not have a material attached to anything. The cubes or the plane. I thought(One of the Game Engine experts here correct me if I am worng) that you had to have a DYN material attached to any object that you would want to be evaluated by ANY of the physics engines,ketji,sumo,ode or bullet

What’s a DYN Material?

Also, I noticed that even though the blocks aren’t flying all over the place, it seems as if my blocks are connected to the ground or something as they are VERY VERY hard to tip over.

Everytime I try to setup a couple blocks, it seems to take a lot of force to tip over the second block(extreme angle-ing of the first block and sometimes elevation).

Many times, somewhere in the chain there will be one block tilted against another block which is standing straight up and the line will stop.

It’s as if there is a TON of friction at the egde of the falling block against the face of the next block, or as if the next block was “stuck” to the ground which would explain why it was so difficult to push over.

Any help would be appriciated, even with copying settings it does not seem as if I can get anything CLOSE to the domino example…

i could be wrong here, but if you using the cube setting shouldn’t the base be equal to the longest side, making it fairly challenging to nock over?

A DYN material? A fairly integral part if physics simulation!
If you add a material to your objects, then press the DYN button underneath the colour settings, you can change the restitution and friction of your objects, plus some other crazy stuff.


I’m having problems with bullet too - I find that unless you have perfect cubes and are using “box” bounds, objects tend to jitter if placed close to each other (even though they are not touching). Objects that start close to gether (not touching) fly apart violently on the first frame.

Can anyone help?


Well I believe you have to have them slightly hovering, because with the way the math is done if they are actually occupying same space, the physics bug out (2 masses in same spot and all).

Its as if they started out inside eachother, so each’s elasticity pushes on one another…


My Default Friction and elasticity in the DYN settings were widely different, so I had non-elastic(bad) and high-friction(double bad) physics so that is why my domino’s didnt work at all.

Thanks for explaining the DYN settings to a newbie, :slight_smile: