Hi Guys,

I am trying to model a LED reflector collimator and following the link by Mark Nicholson. But that is not a reflective surface. It used a compound parabolic concentration object (CPC).

 https://www.youtube.com/watch?v=kpkeze3mvLo

But I am designing a spotlight which is softer in nature (pic attached).

(1)

I believe the basic principle is the same in collimating the beam but how I get this hollow moonlike reflector? Is there another surface structure like CPC that will allow me to do this surface property? 

(2)

Also, I have followed Mark Nicholson’s video (link) and it doesn’t show how I can control the beam width. It has 8 degree beam width I believe in the example, but how I can control that to make it 6 degree or 10?