Lights that cast no light.. only shadows

[inspleak]

Hey guys.. can any one fill me in on how to make
a light only cast shadows? I have a scene lit like I want but I want to make some of the objects cast a particular shadow, so I need a light that doesn't change the lighting of the objects, just makes them cast shadows... thanks so very much for your help!

-Jake

[joojaa]

make the light set the intensity to something very small like 0.001 (wont affect anything, maybe even specular off so that even this wont matter), then using depthmap shadows with a color intensity of something like -1000 for completely black!

Raytracing is a bit trickier, you disable shadow casting for all objects and then ad objecs with no primary visibility as the shadowcasters then by unlinking the shadowscasters you can controll what light cast what shadows!

[inspleak]

Cool.. thanks very much.. I am using depthmap shadows, so I have one more question left..

what exactly do yo mean by shadow color intensity.. how do you make that a negative number? I can get the color picker up, but you can only enter positive values for the colors... thanks so much!

-Jake

[nightshadevfx]

Even simpler to set the lights color to black and set the shadow colors value to -1.

[joojaa]

umm yeah that would be simpler! Also negative spotlights are cool!

[djsmackmackey]

here's an easier way. Make your light color Black, your intensity to negative 1, make your shadow color White.

[inspleak]

Great! thanks guys.. I really appreciate all of your help..

Have fun!
-Jake

[joojaa]

isnt that what NightshadeVFX said?

[djsmackmackey]

He said to make the shadow color -1. I was just saying a different way that would make more sense, since there seemed to be some confusion about how to make a shadow a negative color. There's quite a few ways to do this, really, so any way is acceptable. Just figured I'd give another option.

[moss]

That's really cool DJ! Doesn't make sense to me, but it works! Beats my previous method of making a positive light with a shadow, plus a negative light with no shadow.

[kjaft]

I doubt this is going to help you, but i use Shake for my compositing. You can use Photoshop as well just depends on what your doing. Depending on what im doing i set most of my objects to Render Layers. Then you can just render the shadows under the objects, and composite on top of them. It is very helpful, i konw That weta uses almost the exact same process. When i saw how they made the Helms deep, they rendered all the Orc army and then the shadows they prodcued. one layer was the orc army, under that was there shadows. i just think its helpful but it just depends on what your doing. dont know if this helps.