A light in the window... HELP! :)

RKane_1

Two questions:

How would you best make it seem like there was a light in a window in the distance that illuminated an area WITHOUT being able to make a window transparent? (The set I am using has a block of building material right behind the window material so making the window surface transparent is pointless)

and

What settings (Could be camera or area light settings) would make an area light invisible in a final render?

SpottedKitty

Is the window glass a separate material from the frame and the wall it's set in? That would be easiest, you could put some ambient (not too much) on the material for a fake "glow", and set up a wide angle spotlight just outside the window to illuminate the area. Adding an area light to the window material itself probably won't work, if the light is bright enough for your needs the window itself will most likely be glowing much too brightly.

For an invisible area light, check the Surfaces tab and look for the "Fantom" on/off switch, that sets whether or not the surface is visible.

mjc1016

Hmmm...obviously an area light would be my first choice. But what to use or turn into the light is the question...since geometry does have an impact on how they behave, it may be better to use a plane instead of part of the building as the base for the light.

SpottedKitty's idea has a lot going for it, too...especially if you use one of the ShaderMixer/other spots that can accept gels...that way you can add any details like mullions, to enhance the effect of the light coming out the window.

JonnyRay

I vote with mjc, for something that specific, you'll probably do best with a simple plane with the uberAreaLight shader applied to it. Make sure you have plenty of sub-divisions in the plane, though since area light shaders actually cast lights from the vertices on the surface. If you use the defaults when you create the plane primitive, you'll end up with only have 4 corner vertices, which will make controlling the light much harder.

RKane_1

Does distance play a role in how far an area light shines? Like if it goes past a certain point, it falls off?

mjc1016

JonnyRay said:

I vote with mjc, for something that specific, you'll probably do best with a simple plane with the uberAreaLight shader applied to it. Make sure you have plenty of sub-divisions in the plane, though since area light shaders actually cast lights from the vertices on the surface. If you use the defaults when you create the plane primitive, you'll end up with only have 4 corner vertices, which will make controlling the light much harder.

The trick I've found with area lights is simple geometry and enough 'faces' to give a good distribution, like a 2 ft sq plane with 4 to 8 divisions, will give better light than anything more complex...also making the plane the 'right' size to start with seems to work better than scaling it up, after the fact...also large areas should get more divisions. Problems start to crop up when dealing with curved/smoothed surfaces.

There will be some subdivision at render time...but there's no need to make it a SubD or go overboard with the divisions. Also don't forget to play around with the samples settings...more will smooth things out, but at a slower render speed.

The UA plane preset is a single 'face' plane at size of 1 meter.

mjc1016

RKane_1 said:

Does distance play a role in how far an area light shines? Like if it goes past a certain point, it falls off?

There are falloff settings in the UberArealights...so it is adjustable.

And the Fantom setting should make the mesh invisible in the render...

RKane_1

Also, fiddling with opacity doesn't screw up the normals, does it?

Richard Haseltine

You could use the Polygon Group editor to make the obstructing geometry a separate material, then hide it and make the window semi-transparent..

Jaderail

If all you need is the glow Ambient would be enough. I like the Poly Group editor and creating a new Mat zone just for this. Or a Plane placed properly. Fall off will be a issue over distance in a Area light.