can i do this? i'd like basically to be able to see through it to my background picture, but have shadows when its rendered..

What you are asking won't work. What you can do is load a one sided square prop, position and resize it, and apply your background picture as a texture for the square prop.

What I did once was rendered an animation in preview mode with the ground shadow display on. Then I rendered the animation ( not changing a thing) with the real renderer and composited it over the first one. Only problem is that the shadow will always appear as if the light is dirrectly above the character. Pict, tiff, and photoshop files render with alpha channels- background should be 100% black. You could also use the render with the shadow as background in poser. You could do the whole thing with poser.

I too spent a long time trying to work this out myself. I've concluded that there are two ways to achieve something like this (and if I suggest something already mentioned, I plead ignorance because I responded without reading the entire thread!): 1)Acutally re-build the environment in Poser. It won't look as pretty, but with some careful spot lighting (NOT infinite), you can make a fairly detailed environment, and shadows will cast on EVERYTHING. By "re-building" I mean using primitive blocks and shapes along with textures (much like in Bryce). This is the approach I'm taking with my Poser movie currently in development. 2)Bring up your BGimage in an image editing app (I used MGI photosuite since it loaded quicker than photoshop) and "cut out" the area that the Poser figure will be standing in. Save this area as its own image. Now add a cube to your Poser scene and place it under your figure(s). You'll notice a shadow is cast on this cube as if it were a floor (when rendered). This is not ideal for camera animation (as in, "a moving camera") sequences, since you'll need to position the "front" edge of the cube just out of camera view (unless you make it paper-thin). Now apply the texture to the cube. You'll have to match the texture and lighting, and if done correctly the effect is seemless and very very believable. You could also try simply adding the ground. By default, Poser makes the physical ground invisible, and it therefore does not allow shadows to be cast. Go figure. You could also render in another app like Bryce4 (earlier versions don't support transmaps) or LightWave (the render will be of higher quality overall). I hope all that makes sense, let me know if I need to explain further. Good luck!

Attached Link: http://www.nerd3d.com/nerd3d.htm

Nerd is selling a backdrop prop which is pretty neat. Follow the link to check it out. - Satisfied Customer :)

effected like tis?

here's what behind the magic. c's u couldn't make the prop to 100% transparent,the prop wl make it look like color fliter effective in background, u can do some post job for colour adjust or chose a fliter color u like.