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barbiturat
02-20-2008, 02:31 AM
How to make white environment with relatively small directional and coloured shadows (like in the picture with cherries)? If do it with FG, shadows appears too big, and not directional (as on second picture). If i do illumination with lights, the ground appears not enough white. But if i raise light intensity, everything becomes too light.

How to do such shadows with absolutely white environment?

curbsidebandit
02-20-2008, 05:34 AM
I would think you would need to create a ‘selective shadow pass’ for the ground plane, and a pass just for the object you want to show up. Then in a composting program you would create a white solid (After Effects) for the background and composite your renders on top. The result is your white background, a render of just the shadow on the ground, and the object with shadowing as well.

McKertis
02-20-2008, 08:29 AM
barbiturat
Eh, you're here now too ? Softimage.ru cant answer this ?

I would think you would need to create a ‘selective shadow pass’ for the ground plane, and a pass just for the object you want to show up.

Thats too much bother.
Basically what i do : copy the ground plane and move it a little bit over the old one. The lower gets assigned the Constant white material, and the upper a lambert of any color. Then in the Render Tree for the upper plane you plug a Sprite node between a shader and material, and plug Shadow node in Sprite node as well.
What you get is Shader and Shadow are plugged in "input" and "mask" channels of a Sprite node, and Sprite gets plugged in "surface" channel of material.

tarkovsky
02-20-2008, 08:36 AM
You could do as barbiturat says, which would probably be the most reliable, but you could also set it up easily with FG. Shadows with FG are directional. Put your cherry/red ball/whatever on a white lambert grid and light the objects with a constant white grid from one side.

tark

barbiturat
02-20-2008, 07:15 PM
tarkovsky, thanks! I didn't know, that shadows in FG can be directional.
McKertis, thanks to! I'll try your method.

barbiturat
02-21-2008, 02:06 AM
tarkovsky
But what if light source is on one side? If i use white background, it will be shadow soarce to, and shadow will be too big.

McKertis, what if on a plane several objects, colored with diferent colors? How to do diferent colored shadows on same plane?

McKertis
02-21-2008, 08:19 AM
what if on a plane several objects, colored with diferent colors? How to do diferent colored shadows on same plane?
That depends on what you actually mean by that. Your question can have many meanings.

But basically - the easiest would probably be doing the same way to receive "overlay" shadows on a "dummy" grid, and then just coloring them in XSI compositing module.

ThE_JacO
02-21-2008, 09:20 AM
The reason you have "too much shadow" is because whatever is being looked up by FG gets widely occluded by your object.
If your light panel (assuming that's what you're using) was wider and curved around the object, it would be looked up by more of the ground without being occluded by the object, and reduce the shadow.

For that kind of studio beauty shot look though you'd probably be even better off running a few passes through the grinder, and just using an ambocc pass with a low and short spread for the lookup to div the coloured fg one by.

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02-21-2008, 09:20 AM
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