See also:
Some people say Blender physics is broken. But my tests so far have shown that common physics issues are likely related to not changing Blender’s default collision settings to appropriate values.
Scaling objects to obscene proportions in order to get them to “work” in Blender physics is a hack, not a real solution.
Abiding to real-world scale means that everyone who uses real real-world scale can expect to get similar results using the same values. It means that Blender files and values in those files become interchangeable - even with physics applied.
The more people just mess with values to make them “work” with things that are not physically accurate in size, the less others working similarly can easily reproduce those results.
Having said that…
RIGID BODY COLLISIONS AT REAL-WORLD SCALE
- Working at real-world scale with Blender physics can sometimes yield unexpected and undesirable results. Using Blender’s default settings, rigid bodies may “explode” away from each other or not be able to get very close.
Often, the simple solution is to change Blender’s default collision margin from .04m (4cm!) to .001m.
CLOTH AND RIGID BODY COLLISIONS AT REAL-WORLD SCALE
Problem:
Blender’s default Cloth Collision Distance is “.015m” which is too much of a gap when used at real-world scale with rigid bodies. Additionally, the rigid body “outer thickness” (which repels cloth) default is “.02m”.
Solution:
Changing Blender’s Cloth Collision Distance to “.001m” and any rigid body “outer thickness” to “.001m” and increasing the collision quality reduces the gap between cloth and rigid bodies to “.002m”.
Using real-world scale with Rigid Body Physics in Blender
Even 216 1-inch cubes stacked together with corner vertices sharing space yield expected results when Blender’s default settings are adjusted accordingly.
Using real-world scale with Cell Fracture + Physics in Blender
It appears that Cell Fracture input values are limited when working at the scale of the types of objects humans typically interact with, but physics can work as expected when Blender’s default values are adjusted.
- Not the ideal workflow, but scaling up objects and performing a Cell Fracture and then scaling them down to their original size before applying physics can help reduce the gaps between pieces.
