View Full Version : Emissive material - Wrong Side

12-03-2012, 08:20 AM

I have a problem with the emissive materials. I am applying the white light material to a 3d model of a lamp that consists of 2 sets of opposing panels. Two of these panels work just fine, but the other two don't work. It looks like the panel has a side that illuminates and a dark side, and two of these panels show the dark side instead of the emissive one. Does anybody know how to change this?

Thanks in advance for your help and have a nice day!

12-03-2012, 09:50 AM
You can change the material to be emissive on the 'Front' side or 'Both' sides only... see the material settings.
If you only need one side emitting you could just rotate the parts?

12-03-2012, 12:37 PM
Thanks for the info! I'm right now in the middle of a rendering process, but as soon as it is done I'll try to do what you say, although I don't recall having this option, but I'l look for it! In any case, I read on another thread that the "easy" solution is to change the normals of the model on your CAD software, so it's not a big deal.

In any case, thank you very much for your tip!

12-03-2012, 02:21 PM
Yeah, setting it on Both in the Emissive Material Properties will work, I run into this issue ALL the time.

12-03-2012, 03:31 PM
Okey, now I'm gonna look stupid, but I need to ask. How do I acces this "Emissive Material Properties"? I've never used that! Thanks! (By the way, I'm using Bunkspeed Shot)

12-03-2012, 04:18 PM
I only have experience with Move and Pro, but you should be able to just click on your material in your Materials Pallet, and that should open the properties window.

12-03-2012, 05:00 PM
Emissive direction is based on the surface normals. So, if you have two surfaces and their normals are in opposite directions and you have single sided emissives on each part, you will get light that emits in two separate directions. This is also why there isn't a "back" options for emissives. All suggestions for a solution above are valid so thanks guys for chiming in!

12-20-2012, 02:47 PM
This issue comes up all the time for people. Would it be easier to over 3 options for emissive direction. Side 1, Side 2, and BOTH? or Font, Both and Flip (flip would reverse to other side)

12-21-2012, 01:14 AM
From my understanding it is just not possible for that to happen in iray, otherwise it would make total sense. I'll ask the right people and find out what they have to say.