[Bf-committers] 1) ESC doesn't abort render 2) Bullet physicsproblems

Alexander Ewering blender at instinctive.de
Sat May 13 02:15:52 CEST 2006

On Fri, 12 May 2006, Erwin Coumans wrote:

> Hi,
> There is a lot of ways to make physics not work, and you probably found one 
> of them :)
> Easiest is to look more at the provided samples that work, and see which 
> change breaks things. Usually scaling messes things up badly.
> Scaling, shifting the center of mass, making objects too small (there is hard 
> coded tolerances at the moment) etc.
> Best is to mail me a blend, and I can verify it.
> Eventually some faq should help out.

Hi and thanks for the reply,

well, I wouldn't consider a 20x10x10 cm brick 'too small' :) Indeed I tried
rescaling the scene upwards, and it fixes things. Though, this raises the
question again: *WHAT* does 1 Blender unit actually *mean*? In the past, it
definitely meant 1 metre - for example, the gravitational constant 9.81 gave
realistic gravity if you had 1 BU = 1 metre.

Now, it seems like the problem is not the size of the scene, but that
the hard-coded tolerances are too big.

Also, as soon as I attach a motion actuator to an object with dRot in it,
and I trigger it once, this object starts to absorb dynamic objects
instantly when they touch it, and this behaviour stays through the rest of
the Blender session - even if you remove the actuator. You have to quit and
restart blender in order to fix bullet...

File is here:


Try up/downarrow during play, this works. Then, try rightarrow. Boom,
physics broken until you restart Blender.

Anyway, I think the bug tracker is a better place for this. :)

| alexander ewering              instinctive mediaworks
| ae[@]instinctive[.]de   http://www[.]instinctive[.]de

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