Physical interaction between objects

Question

Is it possible with Blender to have a physical interaction (dealing with contacts) between objects?

For example:

• I would like to make a sphere scratch another object and imprint a permanent plastic deformation on this object.
• I would like a sphere enter inside a cylindrical part (with an elastic behavior) and expand it from the inside.

Is it possible to do this with Blender, or by combining Blender with external tools?

Answer 1

Yes, Blender is absolutely capable of doing this. The feature you are looking for is called dynamic paint.

To do this simply select the object you want to deform, go to the physics tab, click on dynamic paint, and choose canvas.

Then just scroll down to the dynamic paint advanced rollout and choose displace under surface type.

Next, select the object you want to use to inflict the deformation and set it as a dynamic paint brush (just select brush instead of canvas).

Then you can animate the brush object to scratch across the canvas object and it will deform it.

A few tips for using dynamic paint:

• You will want the canvas object to have plenty of subdivisions so that it has enough geometry to get deformed.
• You may want to enable anti-aliasing and add some sub-steps on the canvas object for a smoother deformation, particularly if the brush object is moving fast. This makes Blender sample the motion of the object between frames for smoother painting.
  

Answer 2

You can easly achieve physically believable results by running physic simulation, dynamic paint, keyframed shape keys, molecular add-on, fluids... a mix of all... but remember that Blender is an animation-focused software, so don't expect to be asked just about some real world phisical parameters and let the software do all the work.

First example:

An interesting way to imprint plastic deformation by using a "static" cloth simulation can bee seen in this video https://www.youtube.com/watch?t=267&v=wJFE2pb0Ri4

The object to be deformed is a highliy subdivided, cloth physic enabled, with structural stiffnes set to 0 in order to keep the deformation caused by a second object that has collision physic enabled.

Second example:

No smart idea about. Maybe a fluid simulation (if I have well understood what is your concept about). The cilinder act as a boundary and the sphere emit big fluid particles in both direction...but the interface will never be smooth as an expanding sphere has.