Light plain visible

chriswrcg

If I create a plain primitive and turn it into a light source and then make it not visible in the render "so you can't see the primitive" is the light also not visible or does the plain primitive still produce light?

Enchanted April

Yes it will but you should it not make "invisible". Instead you should set the cutout to 0,0001 or so. I don't remember the exact count for the zeros...

FenixPhoenix

Or you can create a small (90x90) jpeg, fill it with black, then plug that into the cutout opacity channel. That will make the primitive invisible but it will still shed light.

Update: I'm attaching the one I use (always handy) in case you want to use this one.

margrave

Do you even need a plane primative?

You can change the geometry on a spotlight to a rectangle, then set "Render Emitter" to off. It'll light everything up while still being invisible.

I'm not aware of any advantages mesh lights offer aside from being tangible geometry in a scene, which is not what you want.

Richard Haseltine

margrave said:

Do you even need a plane primative?

You can change the geometry on a spotlight to a rectangle, then set "Render Emitter" to off. It'll light everything up while still being invisible.

I'm not aware of any advantages mesh lights offer aside from being tangible geometry in a scene, which is not what you want.

A light can be hidden from direct view but not from indirect (reflections, seen through other surfaces). A plane with near, but not quite, zero opacity is nearly invisible both directly and indirectly.

Skyewolf

FenixPhoenix said:

Or you can create a small (90x90) jpeg, fill it with black, then plug that into the cutout opacity channel. That will make the primitive invisible but it will still shed light.

Update: I'm attaching the one I use (always handy) in case you want to use this one.

It doesn't even need to be that big a single pixel will work. A black 1px x 1px image plugged into cutout opacity. Then you don't need to worry about the haze that simply turning down the opacity to .00001 gives you. :) 

Paintbox

 

A light can be hidden from direct view but not from indirect (reflections, seen through other surfaces). A plane with near, but not quite, zero opacity is nearly invisible both directly and indirectly.

It suddenly dawns to me why they call it a ghost light.