Rendering - Shadow Intensity


Hi -
I have a challenge, perhaps there is a suggestion.
 
I have animated objects that are covered with textures.
They are rotating about a sphere.
There is a single global light acting as a sun.
There is an ambient light set as bright as practical.
 
My challenge is that the shadows cast by the objects onto the sphere are too strong.
I have tried adding a glow to the sphere, but it washed out it's own shadow as much as the shadows of the objects so that the spere lost it's 3d depth.
I have the sphere's surface texture at 30% diffuse and 100% ambient and while that did a lot to solve the issue, but it is not enough.
 
I know the objects can have their shadows turned off completely but some shadow is needed.  My question is whether there is a way to setup the textures on the objects so that they will scale/fade back the amount of shadow they cast - like stencil does, but without fading out the objects themselves.
 
Thanks,
Duke

Try putting a 50% (or 30% or whatever looks good) gray image in the caustics
channel of the textures of the objects which are casting the shadows.

Duke, here's one more piece of the pie. When you want to place a
greyscale map into the Caustics channel, simply press the option(Mac) or
Alt(PC) key while clicking on the "Load.." button in the Image Map
dialog. It will bring up the color picker, allowing you to choose a
greyscale percentage for the channel, rather than building a map in
Photoshop. Works for other channels too, for example, choosing a color
for the Specular Color field. This was an undocumented feature for quite
a while, and may be so still, I'm not sure. Very handy.
I certainly don't understand caustics enough. Is the idea that the
texture is being perforated like a mesh?

This is called the caustics channel, but it shouldn't be confused with real
caustics, which Strata can also calculate, but that is a different deal.
This came first, as a method to fake what came better later.

What this channel does is put a mask in the object's cast shadow. It can
also be colored, so your might want a blue, or purple, or whatever.

If you get the feel for what this channel does, it has some useful
capabilities, the one you have just seen is the one I use most.

I did a job a couple of seeks ago where I had some divider walls on a white
surface. I put a graded grayscale image in this channel, and applied it so
the lighter are of the gradation was toward the top. This gave the
appearance of the shadows diffusing away, gave me a nice look that I would
have otherwise gotten with raytracing.

You can get tripped up using this on more complex scenarios, but it is
useful to have in your bag of tricks.

--
Jean
One further 'down and dirty' method to reduce the intensity of shadow
without reducing overall light or adding conflicting shadows, is to place
two lights in approximately the same place. One has shadow casting switched
on, the other, off. Divide the total required amount of light between the
two to get a setting where the shadows are strong enough and the overall
light level as required

Ah yes, this one works wonders, too.

Posted: Thu - March 24, 2005 at 10:39 AM          

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