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How can I make a spotlight in maxwell? Do I have to fully modeled the whole light? I have a wall with some artwork and I have a recessed light fixture on the ceiling that I want to use as a spotlight.

Thanks for you help.

cheers

locos77 nothing is a dumb question if you seek the answer, In maxwell you have several lighting options:

-Physical Sun
-Sky Dome
-IBL Image based Lighting (HDRI) using High Dynamic Range Images
-Emitter Materials

Depends what you are trying to create, sounds like you might model some basic geometry (poly plane or sphere) apply a material to it and add an emitter layer to it, you can even use IES lighting data, checkout chapter 6 and 7 of the pdf manual.

Cheers

Brett

I used a spotlight to throw a beam of light behind this woman's head
http://www.digitalartform.com/archives/ ... pussy.html

The method I used to create the beam was to put a platonic solid emitter at the focus of a parabola. By making the parabola shinier silver mirror, or more diffuse white, I could change the quality of the beam and spot.







Here is the parabola in .obj format (long, thin y=x^2)

http://www.digitalartform.com/archives/ ... ellip.html



I tried cones and ellipses as well.

http://www.digitalartform.com/archives/ ... ellip.html

The Fresnel lens approach was interesting to me, but I was advised away from it as it turns your lighting into noisy, expensive caustics.

http://www.digitalartform.com/archives/ ... ens_-.html

Here's a faster and a more simple solution:

Use a simple plane for your emitter geometry and mask it like you need.
Attach it on the back of your light fixture (slightly inside) and that's all.
Make sure the emitter's normals are facing in correct direction.




Now, if you make the material of fixture (I mainly talk about the inner side) made of pure black,
it will not cast indirect rays from the spot and the result will look like this:




If you use a lighter fixture color, the emitted light will start bouncing inside the fixture and
it will start to look more interesting. Although, I suggest using high rough single BSDF material
for the inner face of the fixture. That will add a lot of speed.




Controlling focus is as easy as changing the shape of the fixture. In this example, it's more long/narrow.




I'm sure one can add more complexity in this basic setup but,
it's not always good adding more detail if you're also after rendering it fast.

Download Scene

jfrancis wrote:



The Fresnel lens approach was interesting to me, but I was advised away from it as it turns your lighting into noisy, expensive caustics.

http://www.digitalartform.com/archives/ ... ens_-.html

Fantastic test render btw, somewhere on the forum I also have done some nice fresnel tests ( a few years ago )

Thanks

One difference between a collimated beam and a 'barn door' emitter is the beam will not falloff as the inverse square of the distance. Not that that matters that much, but something to consider.

Another difference, I think, but have not tested, is a collimated beam will throw sharp shadows from a 'gobo' or 'cucoloris' over a distance, whereas a cookie near a barn door emitter will produce soft shadows unless the cookie is moved near the target and away from the source.

Also the spotlight circle potentially has a sharper edge, and a little cautic-y detail is easier to produce in the beam strike.

Thanks for everything, those are some great awesome answers. That helps a lot..

cheers

IES is simple solution, sometimes I hide the IES geometry from the camera and use a secondary emitter to fake the fixture

I think maybe the new slide projectors in v 3 are going to be useful for creating collimated light beams? Throw in the volumetrics and they will even form visible beams in the air.



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Upcoming Webinar — Episode 91
Maxwell Render – An Insider’s Look at V3!
Live! Wednesday, October 23, 2013 — 11:00am PDT
http://www.novedge.com/webinar/91



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EDIT:

From what I now understand about the projectors this doesn't sound like it will work.