View Full Version : Translucency Issues

11-23-2006, 10:51 AM
Hi all,

Here's what I am trying to do: I have a room scene with a TV in it, and I want light to shine through the TV screen and into the room.

I put a point light inside the TV. All the TV's surfaces are double sided, with no transparency or translucency, except for the screen. The TV screen's surface is 100% translucent, and its luminosity is set to 100% as well. Shadows are turned off.

The problem I am running into is that the light from the point light still shines through every surface of the TV. So, it's like there's a blue light coming out of the back of the TV too in all the renders, which obviously doesn't make sense. I tried switching the point light to a spot light, but still, the light goes through every surface of the TV, not just the screen. I'm not sure why the light is going through everything (in fact, I een dragged the light outside the room, and it shone through onto the opposite wall!).

Maybe I'm just going about it wrong, but any help would be appreciated. I'll attach 2 screens to show my setup (tv_0.jpg shows the tv light at 0% intensity, tv_50.jpg shows the light at 50% intensity).

11-23-2006, 11:02 AM
raytraced shadows on?

11-23-2006, 11:09 AM
Also, If I'm reading this right, you're going to need some transparency applied to your glass also, translucency alone isn't going to give the effect you want. I think.

11-23-2006, 11:59 AM
Hmm, right now I have all shadows off (except one overhead spotlight using shadow maps). When I turned on shadows, no light came out of the TV, even through the screen (which had translucency up to 100%).

Umm, I just tried turning on raytrace shadows, and bumped the translucency up to 200%, and the tv light intensity up to 10,000%. The screen was very lit up, but again, no light came out of it to affect the rest of the room. This makes me think you're right about translucency not being enough to achieve the effect I want... But if I give the screen some transparency to let light shine through, any ideas on how to avoid the problem of seeing through the screen to the back of the TV?

11-23-2006, 12:15 PM
There lots of ways to achieve this. One way would be to make the polys for the screen only 1 sided, then light would shine through them without being transparent. I would probably adjust the luminosity of the screen also, not relying on the translucency.