casting shadows from inside a texture mapped box

I wanted to use an alpha texture map to make a lighting fixture with a cut-out shade that casts appropriate shadows. To try this, I took a cube, texture mapped a spiral in alpha and put a light source inside the box. The box looks good, but no light is emitted from the box. If a spotlight is put in to the side, it casts a solid shadow.

I’ve attached an image. The box with the cutouts has a “lamp” light source inside. There’s another dull point source way to the left to provide ambient light, and a spotlight to the left to show the cube casting a solid hadow on the purple box.

I’ve read what previous similar discussions I could find, and this is what I’ve tried: For the boxes, I have “Full Osa”, “ZTransp”, “Traceable”, and “Shadbuf” turned on. For the lamp, I have “Ray Shadow” turned on. Any help would be appreciated.


As an aside, here’s a picture with the external lights turned off. Note that while there’s light inside the box, it doesn’t get outside it to illuminate the nearby cube purple cube. I’m using 2.42a on a linux box running Mandriva 2007 RC2.



In the material for the purple box try enabling TraShadow.

Bingo! Dude, that was it. Thanks a load. It didn’t even occur to me that I had to change something on the object receiving the shadows and light. The result is below (I rotated the box a little to make it more obvious).

Thank you so much – I would never have figured this out on my own.