POV-Ray [plugin] (updated: 2016/Aug/08)

[micheus]

BTW, did you notice the images in the post before the "lamp" one.

[img=250x113 link=http://img13.imageshack.us/img13/664/cwpovlttorus1.jpg]http://img13.imageshack.us/img13/664/cwpovlttorus1.jpg[/img]
The torus is a narrow 3 x 3 encircling the cube, both at origin. Two points of interest:

1. The torus is fully "lit," but the cube isn't. I'll check ASAP if dividing the torus will make it a meshlight. (As your previous post seems to suggest.)

I think it's alread divided enough.
The answer you know - at least you talked about it many times these days: It's a point light and it's placed in the center or the area - or, in this case, inside of the cube.

2. Parts of the torus are in shadow. (They should ideally be ambient - or emissive? - 1 or 1+).

Yes, for this you will need to do what I have mentioned before (play with objects' Ambient property and Emissive Filter). Here is the result:

The reflexion in the floor you already know that we can improve it by using v3.7+area_illumination but, it seems that area light is good for objects without hole.
I believe we need another aproach for this situation, maybe using media for object (like we want create neon light - I will try put an image soon)