halos shining through alpha spaces

Is there any way to get a halo to shine through a material that has an alpha channel?

Basically, I wanted to add to the “cutting-through-steel” tutorial having a back-lamp with a halo that pierces through as the steel is cut. However, even though I can see the halo on the other side, the light doesn’t pierce through where the material is invisible. Is it possible to do this? Is it possible to fake it?

Blender does not support this feature.

As far as faking it, it may be possible, but I have no idea as to how to go about doing it. Sorry.


I did something like that, albeit it was for bullet holes, but the idea is the same.

On a separate layer, add a halo spot and turn its Layer option on
Create a mesh with the path of the “cutting” cutted out (on the same layer)
Duplicate the path of the particle emitter and move it to that layer
Parent a particle emitter to the path. A simple plane would do the job well. Make it as small as possible.
For the particles settings, nothing is important except the start and end frame and the number of particles. Keep all the rest at 0 (Forces, Norm, …)
Create a plane a little larger than the width of the cutout section, parent it to the emitter and use it as duplivert.
Now’s the tricky part: You have to offset the path’s start and end frame so that the end frame matches with the start of the particles emitting (“the cutting”).
Say for example, you path length is 100 frames, and it starts on frame 1. You edit the Curve IPO to make it start on frame -99 and end on frame 1.
Change to life of the particles emitting the planes to match the length of the path.

So basicly, the trick is to use particles with duplivert that will die at the same rate at which the surface is being cut, so that the spot will only shine through the part that are actually cutted.

hope that was useful.