ies lights very noisy

First off I have only been able to get the ies addon to work by loading the script into blender and then pressing ctrl+U to set it as default. I have tried to save the script as a .py and installing it as an addon, but it never works. Anyone that can help me with that would be greatly appreciated.

Second, I’ve noticed that when I use ies lights they cause a HUGE amount of noise and really slow down renders. The image I posted is a very simple scene with one ies light, one text object (converted to mesh) and a plane with a couple subsurf lvls added. This render is 1000 samples and I still see noise. Also it took 3mins at 720x540. Yeah the lights look wonderful, but hell I would need a bank of computers to render a complex animated scene. Anyone out there have any advice or tips about using these?

i suspect you not understand what is physically correct path tracer (method used by Cycles) and how it difference from “cool flawless 3d projected gradient painters” as old approach. 1000 samples are very small to Monte carlo integrator, if you get noise free scene with it than you cheatiing, like make/tweak scene such as 99% of visible screen space get 99% of direct light (or 100 % glossy ball with HDRI sky only, no other objects).

About that IES addon, there is some way to get better noise cleaning speed and save physical correctnes, use importance sampling from light with respect to that IES spatial data (fire more light rays in directions where IES have lobes), but it stll not implemented in Cycles. You can try Luxrender and maybe other to get better result. Just FYI, i am now trying to implement same feature, but unfortunately progress too slow, dont expect result in near future.

this is what I suspected. No I don’t fully understand how ies works or what a Monte Carlo integrator is at all. I always figured ies was just a script that made a mesh that resembles the actual lights in reality (shines rays in more or less the same way as real lights). thanks for the response. I think this is a feature that most blender users don’t use. I did a rerender at 2000 samples and got a pretty clean image, but it took 26mins @ 1680x1080.