Shadows

how to make the own shadow of an object lighter than the dropped shadow? better-> lighter to the color of object not to grey color

Either pre-darken the image face, or use an ambient lightsource to lighten the shadow.

The ambient light could match the general color of the surface you're throwing the shadow onto, and then set-it up either as a fill light, or with no shadows.

where I can find ambient light ? (autocad 2011 arch) it is a second light near my distant light , or it is for sun position

with sky background and ilumination is the effect that I need but the sky is enabled only for sun but if i need only a distant light

"Ambient light" is more of a "how you use it" term, rather than a specific autocad light type. At least in photographic terms.

Ambient light is sort of like light that's colored by the objects it bounces from. For example a clear blue sky radiates light of it's own, which is a bluish white. We don't normally notice it with our eyes, because our eyes/brain just takes it into account naturally, but an outdoor photo differs from an indoor photo, due to ambient lighting (and differences in light sources).

When I need ambient light in AutoCAD, I fake it by using slightly tinted additional lighting., and do it from whatever distance the real ambient source would be. Or, I add a bit of ambience to the materials itself.

In AutoCAD they call a material's self-lighting properties it's ambience level. Not totally sure why that is.. but editing a material, and turning that property up will likely get rid of deep dark shadows on it's surface (to some degree).

I'm not going to get into the science of AutoCAD shadows, because it has likely changed a bit since the 2004 version, but shadows in my version are "Applied Darkness" rather than a true absence of light..

It get's deep black shadows like it does, due to minimized light bouncing capabilities (and therefore limited, or non-existant ambience). The material ambience counteracts that to a certain extent because it pretends to be "pre-lit".. which is what I acheive by throwing in extra low-level non-shadowing lights with slight tints to them.

just have to be careful with extra lights because of the increase in rendering time, and how.. say, a blue tint, might interact with a material surface that's already "blue", or possibly even already lightly tinted blue due to the lighting that was used in the original photograph of the material. The result is sometimes an unwanted "bleaching" effect, where colors seems to bleed a bit.

If I run into that, I go into photoshop, either in post production (after the rendering) to fix stuff, or pre-production (before the rendering) to slightly alter the original textures.

Some folks even "prebake" their textures, which means that the effects of lighting/shading are determined and added to the material image map prior to rendering. That significantly drops rendering times, but can become a very complex job to set-up if your 3d software doesn't have a method of doing that for you automatically. Some systems do, but to my knowledge, AutoCAD doesn't. Basically, you'd be "manually" drawing shadows/gleams and stuff onto the material textures before applying them to the materials in the rendering.

Something like prebaking is used a lot in 3d first-person games, more than static (non-moving) rendering like AutoCAD, because game engines are realtime rendering systems, and it's a method of enhancing realism without dragging down the render times.

thank you, I have to make some experiments

I found here at render a option- indirect illumination->global illumination, it was turned off,

thank you, I have to make some experiments

Yeah.. that's how I found what worked for my situation.. a whole bunch of experiments. Then when I starting doing a different type of render subject, I found that the old solutions didn't work as well anymore, so I had to find new methods again.

*edit*

Cool, "Global illumination".. hope that works.. and yet another reason for me to upgrade, thanks for the feedback!

I appreciate the offer, but you'd probably better erase those posts before a mod does.. we can't discuss that kind of thing here.

Viktorik, if you're implying that you can provide Mike with illegal software, I suggest you stop right now. We do not indulge in that type of behavior here. I have removed your previous posts.

ok,

I am pro illegal software because it's for home use only, I dont have a company that make money for me, and I am student I have no money but I want to learn all , with all options accesible

If you're a student, you can download the educational versions of most, if not all, Autodesk programs from the Autodesk Education Community. There is absolutely no good reason for you to be using illegal software.