[RichG]

Is it possible to control the cone angle of a projector. I'm shining a projector through a volumetric onto someone's face but I have to put the projector very close to the face and the beams are radiating out in a 90° cone. I'd like to pull the projector away and get the beams more parallel, not as fanned out. Tried the spotlight trick of putting the projector inside a tube to focus it but, as I suspected, it wasn't the answer.

[RichG]

So that'll be a no, then!

[eric nixon]

You can use the map to control the cone....black area of the map emits no light,... map is spherically projected.

[Mihai]

Yes, it should work. You can get a very narrow beam if you want. Try turning off tiling in the map parameters if you don't get expected results.

[RichG]

Spherical mapping? That makes sense now. Because we are required to use a simple plain, I'd assumed it was simply flat mapped to that and I was using a square image. If it's spherically mapped I assume that the left and right 25% of it are dead zones as they will be wrapped around the back of the plane so not emitting, is that right? It's a shame in that I'll need a huge map to get decent resolution in the focus area but there you go. I shall carry on my tests. Thanks for the tips.

EDIT: Actually not too bad. I reduced the scale of the image area to about half the depth of the image file and it narrows the beam considerably.

[eric nixon]

I think its like ies, you use a sphere, or a piece of a sphere, and Mihai reminds us, by disabling tiling but still using repeats, you can use a small map.