I read your post about this over at elysiun, but I didn't see this client thing mentioned there. Now that you've told us - I would like to express my concerns:Manuel wrote:A client can ask me to simulate a
illumination using a exact model of lamp.
Blender, along with many, many other 3D renderers doesn't really do physically corrent illumination. The radiosity solver might perhaps do so, but I wouldn't trust that.
So if you really want to simulate the exact effects of your lamp, you'll have to look elsewhere. This would mean a much more advanced renderer with explicit physical correctness. As far as I know, you've got two choices: either 'Radiance' or 'WinOSi'. The latter is exceptionally correct, though it needs several days, maybe even weeks to complete a render.
Links ---> http://www.winosi.onlinehome.de/
EDIT: You will also need to know the correct values for the albedo, or 'reflectiveness', of the walls, floor and ceiling in the environment where the lamp is supposed to be shining.