# How to create a drilling effect?

I wan't to show a drill drilling into a surface. I can't however, create the effect of the surface being ripped up by the drill. I'm trying to animate the shavings of the surface, to give it a believable appearance

I've created the jaw and I've imported an .stl drill that will work for the video. I am able to do the basic animation, but when the drill is going into the mesh, I cant seem to figure out how to have the section of the mesh "follow" or be removed from the drill depth, meaning that the hole left over after drilling.

• How about using a particle system to create some flakes of bone and a Boolean modifier for the hole? I'm not sure what you mean by "have the section of the mesh "follow" or be removed from the drill depth". – gandalf3 Sep 10 '13 at 22:36
• What I'm looking to do is drill a hole and when my animation moves the drill into the mesh, how do I show that section of mesh as removed? Basically I want to grow a hole. – Nick1018 Sep 10 '13 at 23:02
• There are several solutions (ideasman posted some, I could add dynamic paint with displacement), but they depend on the requisites of the animation. Do you need the bone, especially the section of the bone to be textured? – DavidGasku Sep 11 '13 at 8:27

## The following approaches could work well:

### Boolean

(Where an invisible object is used to define the empty space), This is the most direct answer and it can probably be made to work, but also may have problems if the jaw is a non manifold mesh. As a workaround in your case you could remove a part of the jaw, add a inset that the boolean operates on, this makes the computations much more simple but then you need to make sure the seams between the inset and the rest of the geometry are not noticeable.

### Deformation

Where a bone or shape key is used to deform the mesh to create the hole, this is fast and predictable but has some possible drawbacks. UV's & vertex-colors etc will distort with the mesh, drilling multiple holes in the one cavity (where the holes overlap) becomes difficult. (something boolean can do). The key to making deformation work here is creating the geometry so the deformation looks good. and you don't loose volume around the deformation in an unrealistic way.

### Mesh replacement

Replace parts of the mesh over time by animating visibility, may seem a weak solution and has the disadvantage that the animation wont be smooth and you have to finalize the mesh before making duplicates.. but it gives a lot of control.

## Other options which I think wouldn't work so well but including for completeness:

### Compositing

Sometimes you can use the depth to do operations you might assume you would need to do on geometry, there are tutorials showing clever use of depth buffer for similar tasks.

### Metaballs

For certain cases negative metaballs can be used well for this effect.