cant get rid of splotches.

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

Hi!

I need help getting rid of splotches in my rendering, I use quite high settings on the irradiance map

Min rate -3
Max rate 1

Irradiance map:

HSph 50
Inerp samples 30
Clr Thresh 0,1
Nrm Thresh 0,1
Dist Thresh 0,3

secondary bounces
Quasi-monte carlo

Subdivs. 15 bounces 7

Adaptive subd sampler set to min 0 max 4

I have tried playing with the adatptive sub D sampler but that doesnt seem to do much at all a setting of 0 to 4 looks the same as 0 to 8, there is almost no direct light on the walls and there in lies the problem I think. I have a hard time getting a sharp render, it looks like the image sampler smoothes the image to much and creates these small splotches. Maybe I am going about this the wrong way? Grateful for any help I can get :slight_smile:
regards Tobias

link to image
http://www.svenskdesignab.se/lounge\_chair.jpg

2

try changing your min rate to like -7. and your max rate to -1. see how that looks.

3

Did you mean -7 -1 on the irradiance map? it looks a bit smoother but the splotches got a lot bigger, I’m thinking of going for monte carlo on my primary bounces too because i don’t mind noise and our render farm can handle it, even though it will probably take all weekend doing the 200 frames I need. Or do you have any other tips and trix?
regards Tobias

4

Try the high preset and work the numbers after that, are you getting any warnings from the VRAY window? Might be an over bright causing the issue as well.
Cheers
Mike K

5

or coplanar geometry.

6

do you have vray lights outside your window? and are they set to store with irradiance map? If so, try unchecking that.

7

I use the “Very high” setting, the light I use is one target direct with vray area shadows. The pictures renders pretty dark so I use the color correct in the framebuffer to make it brighter ( I learned this from a Gnomon DVD) , maybe this is what “brings” out all the noise. I will do some more testing. by the way I don’t think there is any problems with the geometry since everything in the shade looks splotchy, and there is quite a lot of stuff in the scene. btw Vray gives me no warnings…
Thanks!
/Tobias

8

You probably need more light in the scene, it’s hard to sample dark areas. Is adding light an option?

9

If you do want the vraylights stored with the imap, make sure to up the samples to compensate (64 subdivs is usually a good starting place)

10

From the settings in your first post, change the clr treshold to 0.35 (IR map). Going lower than 0.3 is only needed if you want very fine GI detail with the IR map. Maybe also increase the hsph subdivs to 70 or something.

This has nothing to do with AA, these are GI splotches, so to test it you can even use low AA settings it won’t matter.

11

Thanks! I will try that!
/Tobias

12

Have you placed a vray plane light inside the window ? Mostley makes you spots go away.

13

Thanks! I will try that to first thing monday :slight_smile:

regards
/Tobias

14

Is the model near to x,y,z = 0?

15

Hi again!

Upping the hemispheric rays to 80 seems to have done the trick. but I will do some more testing. I have a Direct light as a sun that sweeps through the room, for that I will probably have to use Monte carlo, but for the stills irradiance map is fine. the stills are over 3000 pixels wide so storing the Irradiance map speed things up a lot.

Thanks all for your advice!
regards
Tobias