Light splotches in simple grid mesh

V-Ray V-Ray for 3ds Max Issues
1

Hi,

please can someone tell me how the render settings shoud look to get a correct result of my scene.
It is very basic - a geomtry grid and in some of the holes are lights which should only affect the single hole itself - and not the segments next to it.
Although when i increase the quality some light will be still visible outside each box.

Here you can dwnload the scene which does cause the strange result. Made with 3ds Max 2011, Vray 2.40.04
http://www.screenpix.at/kundenbereich/direct/light-splotches-test.zip

thanks, best regards
Simon

light-splotches.jpg
light-splotches.jpg1093×458 54.4 KB

2

in LC, switch on retrace threshold and set it to 1.
In IRMAP tick “Check sample visibility”

you can also lower your shadow bias of the vraylights

(I didnt check your file, but those will be my 1st geusses)

3

Hi Simon,
In addition what Morne said, I’d like to recommend these settings for GI to start with
1. For Light Cache increase the Subdivisions and decrease Sample size. Let’s say 1200 to 0.01 (Screen scale). Turn “Store direct light” and all the filters and pre-filters off.
2. If it’s possible, switch the IRMap to Brute Force. If not, use High Presets, Increase HSph subdivisions to 100 and decrease Interpolation samples (20 or 10 for start). Turn “Check sample visibility” On. If necessary, turn the Detail enhancement On (Let’s say World scale with radius 100cm and subdivs 0.5 for start)
Also, check if your geometry is correct.
Hope it will help
Dmitry

4

The most important parameters in these case are:

1.Interp. Samples in Irradiance Map
2.Light Cache Sample size

In the example bellow I’ve decreased the intensity of the lights to 35.
Scene File ==>

1.jpg
1.jpg464×1060 77.9 KB

2.JPG
2.JPG834×600 20.6 KB

light-splotches-test02.zip (53.2 KB)

5

Thanks for the suggestions.
They all lead to the same solution. I tried all, but the Interp. samples inside the IRMap is quite important - if it is set to a higher number, the splotches will apear again even when the settings are already high-quality.
Unfortunately the rendertime is a lot higher than you would expect on a scene with all kind of stuff in it.

I will run some tests on how to speed it up. Thanks a lot.
Simon