poser allows to have ground shadows during the edit process. but this shadows disapear, if i render a figure. is there any change to get such shadows into the rendered pictures ?

Yes, but you must paste this ground shadow into a background. You can import any picture as a background or if you like just a blank image any colour you want. Then, antialias your document first so that the shadow edges will be smooth (DO NOT RENDER first or the shadow will disappear) After you have antialiased go under Display/paste into background and your shadow will have become part of the background image. Now you can render and although technically the shadow disappears, the one that was pasted into the background will remain.

That shadow is just a guide, but with the right lighting you can get shadows cast onto an imported prop floor. -JH.