Maxwell Render | Official public forum

...

...

You CAN model a Fresnel lens and use it, and it will work exactly like you expect, but it will also turn all your lighting into caustics and take forever to clear up. As an alternative, though only an approximation, you can bury your emitter inside a "tube" to help create a spot. I've done this to fairly good extent on a number of occasions for exactly this reason. Having emitters with a "spot-like" angle control for this sort of thing has been on the wishlist for a bit...


_Mike

...

mverta wrote: Having emitters with a "spot-like" angle control for this sort of thing has been on the wishlist for a bit...

This would be a much welcomed feature. It could be as simple as an angle of dispersion setting: zero for pure parallel light (like a laser beam), 90 for unrestricted dispersion (like it is now). Would save a lot of time - especially for the archvis folks so they not only don't have to model accurate lamps, but will reduce the amount of calculations needed to reach a solution. Less geometry, less bounces.

Yes, we have a number of photographers here... you can currently simulate grids the same way, either with geometry, .mxi textures, etc. I recently simulated a 40-degree grid using geometry to good effect.

_Mike

...

In the last project, I actually modeled a Lumedyne 40 for use on the "flash"...

_Mike

The tube trick (called a snoot in my studio days) worked pretty good for me. I just found that I had to make the emitter smaller to get the light to feel harder and more like a fresnel. It's not the same exactly, but it's pretty close.

Hardening up the light just meant I had to pull the emitter/snoot fairly far away, really shrink the emitter to a point, and make the snoot longer. Anyway, worked pretty well for me.

Good idea on the grid trick though - have to give that a go.


b

Don't forget to make the snoot black!

hehe

try this. Make a octagon, reverse the normals. remove every second polygon on the upper 45 degree. Apply an 'inside the studio' texture to the inside of the octagon. black otherwise.

change the lighting to ambient white at about 500 or season to the taste.

the light spills through the 4 open 'ports' and produce decent results without a single emitter.

this can work for images also, creating a clipmap where the bright areas are become transparent. Mapping the image to the inside of the shape (in this case octagonal). If the object is set to glow without emitting light (lightwave) or something like that in maxwell. or if it glows I assume it puts out light. Anyway, the light spills through the 'lightholes' and you can produce decent HDRI-like results without any actual lights in the scene.

cheers.

...

...

It only took you 2 years?

...

jfrancis wrote:
This forum needs better moderation. too many junk posts.

If I wanted to be at eatpoo.com I'd be there.

Ahh, I was just messin with ya... (hence, the laughing smiley)

I'll not do that again! No sir!

Consider me moderated.