Problems with trees

[Gonzalo]

Hi,I have a problem with making trees in 3dViz4. I received the RPC demo with the VIZ4 software and have been rendering with no problem. The problem arises when I try to use radiosity for an exterior scene with Daylight. Since I have only one light source (the sun) when I see the tree from say 90 degrees from the sun I see it in shade. Same problem with using bitmapped planes, whe I apply a lookat modifier the trees look right but the shadows look wrong, In previous works, since I had several lights the trees would get illuminated by some of the lights, but not now. tried adding other light to the scene but it doesn't add light (maybe my mistake. If anybody here is using trees with radiosity , could you please tell me how? I swear i am running out of ideas.

 

Thanks a lot

 

Gonzalo

[nisus]

Hi Gonzalo,

 

We discussed a similair topic a few days ago.

check it out at http://www.cgarchitect.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=23;t=000009

 

Here is an extract:

The problem of opacity-mapped people perpendicular either to the camera or to the sun can be solved, though not too easily. First you'll have to make your planes 'look at' the sunlight. Second render a very high bitmap of only the people in your scene, using the sunlight as a camera. Next you'll save the alpha channel as a bitmap and use this map as a projector image. Maybe you'll have to invert the image.

Eventually make your planes look at the camera and render.

 

rgds

 

nisus

[Gonzalo]

Interesting idea, thanks. What about lighting, a Direct light parallel to the camera excluding everything but the trees and excluding them from radiosity? I'll try that now.

Thanks again

 

Gonzalo