Plasma Cutter

Getting this effect to work took a few different elements working in concert with one another. First, I created a 3d model of the jagged edge left when plasma cutting metal. I baked the normals of this model into a tileable trim sheet texture. Next, I created the metal sheet. I cut the model in two and added a bit of geometry to either side of the cut. I unwrapped the object's UV2 to position my trim sheet along the cut line, making sure the beginning of the cut was at 0. In engine, I authored a shader that spread a glowing line across the cut and revealed the trim sheet.

I wrote a script that causes the light to flicker by adding two sine waves offset by the golden ratio (this is my favorite cheap flicker method and I use it often!). If I were working on a project with a lot of flickering lights, I would consider doing the flicker in the shader, and just passing some parameters from the light to define flicker strength and speed.

To finish things up, I added a flare (a billboarded non-depth-testing quad), some spark particles I painted in Krita, and a smoke shader on a little trail of geometry.

My next step would be to dynamically generate the cut and accompanying trim geometry at run time because of course players want to control the plasma cutter themselves!