Emit Shadow

Is there a way to darken the cast shadow on the pink sphere?

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Hi,

Turn down the Emit value. Emit is for objects that are glowing. Although it doesn’t actually cause them to light other objects in the internal renderer, it reduces the amount they are affected by other lighting.

Add second lamp, turn on “OnlyShadow” button,change shadow color to black, increase Energy value and copy location from first lamp(light emitter).

I understand what Emit does. Is there any way (work-a-round) to make the cast shadow on the pink sphere darker without lowering or turning off Emit?

There is a white (1-1-1) object in my current project that doesn’t render bright enough, so I increased Emit for brightness which also lightened the shadows cast on it making them too weak. I want darker shadows on the bright object.

Maybe I should ask in a different way. Is it possible to brighten the already white object without increasing Emit that will allow the shadows cast on it to remain the same shade as before?

I think you could do that with nodes. Simply run the shadow pass through a curve filter with a “S” shape. This will allow you to “strengthen” the shadow that is already there.

I duplicated the original lamp then did everything you said except Copy Location. Problem solved, Thanks!!

Now, all objects in the scene get darkened shadows including the Emit object. Is there a way to tell the lamp to cast a shadow only on one specific object?

Yes, it is actually per material, however. Add the shadow only lamp to a group with a unique name. Then select the object and type in the name of the group in the material for that object. That is why it is actually per-material. If other objects share that material, they will receive the influence of the lamp as well.

I still don’t think that will work. Emit isn’t really an emit value. It’s a floor value. When it’s enacted at, say .2, the darkest any portion of that mesh can be is 20% of the fully lit value.

You can assign a negative light to the emitting sphere only and then the light on the right side can have something darker to cast a shadow on.

I found the Negative Light button, but can’t figure out how to Assign a lamp to the sphere. How is that done?

The Layer button only illuminates objects in the same layer as the light. Sounds like that will do what I need.

Here you go, my shadow only light casting over an emit. Harky is right to doubt, after he posted, I thought “He’s right, it won’t work.” But I tried it out and it does work. You can control the shadow darkness with the shadow color of the LampShadowOnly light.

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ras_shadow_on_emit.blend (311 KB)

Hm. Obviously you’re right. I think I was confusing Emit with Ambient.

edit: Just checked, and it is in fact Ambient that sets a floor for shading. If you crank up Ambient in World, you can’t get darker than that, no matter what. Not that it’s relevant to the original question, just a point of fact.

@Atom: Great solution with lamps group and Exclusive button. Thanks :slight_smile: