Fluorescent Lights with DMap Shadows

# 1 15-06-2012 , 10:34 PM

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Join Date: May 2012

Posts: 10

I am trying to model a building with 10 individual fluorescent bulbs linked together around the edges for lighting. (basically these... https://www.cpsc.gov/cpscpub/prerel/prhtml03/03145b.jpg) Anyways, I have everything modeled exactly the way I want except the lights. I currently have point lights in the middle of all the tubes, but they aren't doing the trick. I have to use Raytrace Shadows and the light isn't flooding the room like it should. Too many intense shadows.

Long story short, it takes way too long to render with the raytrace shadows. I need to switch to dmap shadows to save render time. I tried using spot lights, but the edge of the cone was causing an unwanted shadow line. HELP!!!

What type of lights/light settings and render settings should I use?

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# 2 15-06-2012 , 11:34 PM

Technical Director
Join Date: Feb 2004

Posts: 2,988

The correct way to do this would be to use mentalray with a light shader; but it seems like you're using software. Anyhoo, you can use a single volume light. Change the light direction to outwards, and the light shape to a cylinder. Then, put a self-illuminated material onto the tube. Scale the volume light to the size of the tube, then in light linking, make sure the light ignores the tube geometry. Done user added image

Imagination is more important than knowledge.

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# 3 16-06-2012 , 09:56 AM

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Join Date: Feb 2010

Location: Australia

Posts: 4,255

This has intrigued me for many moons...cheers ND...giving the Mental Ray one a shot...if that fails...try option 2....I must say I didnt find much literature on how to use or do it in MR...am heading to the Maya help files to have a browse.

Cheers bullet

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

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# 4 16-06-2012 , 07:35 PM

Technical Director
Join Date: Feb 2004

Posts: 2,988

If you want to do it in Mental ray, create an mia_material, and under advanced, map a mia_light_surface node. In the color, map an mib_blackbody. In the blackbody, set the temperature to 7500 (cool-white) and leave the intensity at 1. Go back and map this blackbody to the mia_material's color as well. Go back to the mia_light_surface node, and turn the Fg Contrib to 1. To make your light brighter, play with the intensity and the Fg Contrib. (It goes without saying that you'll need to enable final gather)

If you want your light to glow, and you don't want to do it in post, you can map the output value of the mia_material into the color of a surface shader, assign the surface shader to the object, then use the glow there.

Hope this helps.

Imagination is more important than knowledge.

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# 5 17-06-2012 , 02:06 AM

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Join Date: Feb 2010

Location: Australia

Posts: 4,255

Thanks ND......duly recorded in notepad LOL. I did find a tut very similar but without the blackbody bit...involved the light surface, the FG contribution and attaching a light to it...but will try yours today...thanks again mate.

cheers bullet

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

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