For example, how can we make the strength of the shadow of a weak light source 500% ?

100% shadow is black, so there is no way to get darker than black.  If you want sharper edgesto the shadow change the shadow settings on the light source to disable soft shadows.

Thank you for your response.

 I tried it with Poser.
The shadow of a light was not black due to the other lights.
Poser could set the strength of the stronger shadow, and it indeed made the stronger shadow.

Interesting question.  In the age of global illumination it would be nice to be able to punch up the shadows on a per-object basis once in a while.  Unfortunately, the only way I could think to do that would be to render a separate shadow pass and composite.

Sorry, let us know if you figure any better ways out.

I am a bit lost about this post.

In Carrara you can adjust the power of the light, and the strength quality of the shadows, for every individual light? AND, then you can go into all the other light modifier/effects stuff.
(Select which light only lights up which selected object etc!)

Brian

OP may be referring to the fact that poser's renderer (FFRender) does not obey the
laws of optics and physics in regard to lighting, ranging from the obscure to the
painfully obvious.  see poser forum for examples of these.

however, if OP can post an image of the appearance of shadow desired, the experts here
can assist in achieving that effect.

I find it was tricky to get the really dark shadows like you can in Poser. 

Using short ranges and high falloffs (range and angular) with the shadows all the way up to 100% gives you darker shadows.

I put up a freebie light set that renders pretty dark shadows here:

http://www.sharecg.com/v/28074/material-and-shader/V4-Skin-Shader-kit-and-Lights-for-Carrara-6

Any suggestions and improvements always appreciated :)  But I hope it helps you render the shadows you want.

:smooch:

Indi.

I usually just reduce the ambient light to 0 and if using realistic sky, I cut down the global brightness.

Bwtr、

I was talking about the “cast-shadows”,
and it was spelled out by Dwarg that in the age of global illumination it would be nice to be able to punch up the shadows on a per-object basis once in a while.
If we use many lights, the intensity of each light can not be too strong.
The cast shadow from one light is weak.
Some times we want a cast shadow which is not too weak.
It is nice to have, for instance , 300% shadow for the light source (Poser, and Vue can do it).

**As Miss Nancy pointed out, it does not obey the laws of optics.
Who cares ?
We are interested in art (just illusions), and not engineering.
 
sparrownightmare

I usually just reduce the ambient light to 0 and if using realistic sky, I cut down the global brightness.
 
The ambient light is important to have a nice skin of poser doll sometimes.**

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I like the effect I usually get with a nice neutral color mid luminance directional light and a very weak backlight.  I don't like the washed out effect you sometimes get with the ambient lighting.