How to exclude an object from casting shadow on certain object

[roboz]

Hi there,

Maybe I'm missing something but is there a way to exclude an object from casting a shadow on a certain object? Here's an example: I have a sphere sitting on a ground plane. Above the sphere is a rectangle which casts a shadow on the sphere but also on the ground plane. How can I exclude the ground plane from receiving a shadow from the rectangle? Or how can I exclude the light from casting a shadow on the ground plane?

I hope that makes sense. Maybe there's an obvious solution but I just can't think of anything right now.

Thanks
Alex

[Sekhar]

For the ground, you can uncheck Receive Shadow under Object Properties -> Render.

[oDDity]

Yes, but then it's won't recive shadows from the sphere either, or anything else. If you turn off shadow casting for the plane, then it won't cast a shadow on anything, not just the ground.
You should do a composite image. Take two different renders, one with the plane and one without, and put them together in photoshop.

[roboz]

Thanks oDDity. I was hoping I'd missed something but I guess there's no other way than putting it together in PS.

[pooby]

You can do it with cloned lights that only affect certain items and items unseen by camera.. a workaround

say you have a ground plane, a sphere and a rectangle.

Light one affects only the sphere and the rectangle, so the rectangle casts a shadow on the sphere but the ground gets no light.

adding an identical light (light2) that only affects the ground will mean the ground is lit up but wont recieve shadows from the sphere or rectangle.
But if you want the sphere to cast a shadow on the ground, you can clone the sphere, have the clone unseen by camera, but affected by light 2.

It will cast a shadow, appearing to be from the first sphere and it should all look as you want it.