Hi guys I've been having some trouble with IES / down lighting recently. When adding in IES lights things seem to take 3-8x longer to render due to all of the additional noise.
The 1st attachment shows the scene lit with just an HDRI and an emitter material for the ceiling light, render time ~ 15 mins.
The 2nd attachment has all of the IES lights enabled (photometric light type in max with Corona shadows ticked), render time ~ 40 mins
The 3rd attachment uses a very dark HDRI and all of the IES lights enabled. This one took around 50 mins, you can see the extent of the noise...
All renders are using the same exposure with basic render settings (HD cache, adaptive: 4, latest daily build) One thing that did strike me as odd is that I had to crank the lm values of the lights to 35000.0 else they were too dark. Exposure is set to 2.75, highlight compression is set to 4.
All glass is set to hybrid mode, the pool is a single plane set to onesided (solid), but with "casts shadows" unticked. Trees are opacity mapped and the RGB of all white materials are set to 180.
Also I'm rendering this on an overclocked 3930k with 32gb ram. I completed the Corona benchmark scene in about 3 minutes 20.
I don't particularly need to use IES lights, I just need some down/spot lights - so anything that can shave some render time off will be a massive help.
Thanks for all suggestions / tips!