Is there was way to cut a shape like this

I want to animate the “cutting out” of a logo with a laser or cutting torch
Something like this:

Now I have done this:
Curve paths and displacements etc…

Any tutorial on this, old or new?

Start with modelling it, because you’ll use some of the modelling elements for your animation.

Start with a block and a text object. For this example, which is smooth shaded (or autosmoothed) you can get away with booleans, which are easy-- don’t have to worry about topo.

Duplicate the text object and give it sufficient extrusion (in properties/object data/geometry) to go through the block, then convert to mesh (alt-c -> mesh). Enter edit on the text-mesh and remove doubles by merging by distance (m->distance.) Make two objects from the block (duplicate the block), using a boolean modifier targeting this text-mesh, first on difference, second on intersect. That gives you the block object and the text object. For each of these objects, set them to flat shaded or to autosmooth, or else you’ll get weird normals from bad boolean topo. Apply the modifiers, then delete the text mesh.

Give the new text object rigid body physics and enable “animated” in properties/physics/rigid body/settings, then keyframe the “animated” trait. Separate out the individual letters of your text object (in edit, p->by loose parts). Set the origin to geometry for these (select all, shift ctrl alt c -> origin to geometry.) You now have several individual rigid bodies. For each of these rigid bodies, move the keyframed “animated” trait to the frame before the frame you want them to start falling, then advance a single frame, uncheck “animated”, and keyframe.

Return to your original text object. Disable extrusion on it. Convert to a curve (alt c->curve). Separate each individual curve to a new curve, probably by selecting linked (hover mouse over handle, ‘l’, p->separate). For each of these curves, set the origin to the location of the first control in the curve. Create an empty (at the world origin) and give it a follow path constraint for each of these curves, then create an additional empty at the position of whatever is emitting the laser, and have the first empty damped track (another object constraint) that second empty. This is your beam, and you can parent whatever mesh to it you want.

Set the follow path constraints to fixed position. Keyframe/animate the offset factor to move the empty along a single curve. Animate the influence to change which curve the empty follows-- you should be following no more than a single curve at any point, and if you want pauses, there should be times that you don’t follow any curve. At these points, copying transforms from the second empty (the target of the damped track) may be ideal.

Create a floor, with rigid body physics set to “passive”, probably as a cube with cube collision (cube collision is better than plane/mesh collision.) Do not bother giving the block body any physics, as it will just create friction and give you collision problems, and it’s unnecessary.

Create a mesh for your laser and parent it to this empty. Create particle and smoke simulations. I won’t get into these techniques, as they’d be better asked on the material board and the particles/physics board respectively.

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Thanks! I’m going to give it a try :slight_smile: