HDRI flickering on some geometry

[zeilveen]

This is strange stuff, Im working on an animation of a small village and Im doing the surrounding area as simple boxes. Im importing DWG files straight into MAX and extruding the houses. Some houses are flickering (about 1 outa 10). The shadows are seem to go on and off every so frames. Its just for these 1 out of 10 houses but its so anoying. I've checked the geometry of the houses and that seems fine. The material of the houses is just plain Vray with nothing except a red colour.

So far I've spend 8 hrs trying to clear this problem and my deadline is getting too close now.

info:
VRAY 1.4704 with MAx8
Light setup = HDRI in enviroment slot and reflect slot
One Omni light set to OFF

Things I've tried:
- Other HDRI image = no help
- Changed almost every render setting = no help
- Changed all HDRI settings (angular/mirrored ball/ etc) no help
- High AA / High GI / High Subdiv = no help
- Only thing that helps is rendering without HDRI and use Vray Light Dome
but thats just not what I want, but will do for the time being.







Many thanks for any good advice and would like to get to the bottom of this, I must be doing something wrong and hope someone comes up with this tip.

Cheers
Ronald

[Joost Ink]

did you try to increase secondary rays bias?

[zeilveen]

Thanks for your reaction Joost,

I've tried setting second bias to 0.5 50 and 500 but no effect to the flickering. Good tip though I didnt try this one!

Ronald

[Joost Ink]

its probably in the HDRI, me thinks.
I remember a topic about that some time ago, you should do a search on that.

[zeilveen]

Im not sure, I tried to look for other posts but could not find one that might point to my problem. I've uploaded the file to my website and if anyone could have a look that would be great!

Herehttp://www.zndesign.co.uk/houses.zip

Many thanks,

Ronald

[Joost Ink]

your scene is far from its origin, try to move it more towards 0

[zeilveen]

First test shows improvement !!

Im rendering high settings now over 100 frames, I think this is just another mystery solved!!

I knew DWG have this 0,0,0 in Paris and so creating very of centre coordinates in MAX. I've had this problem before but didnt think of it!

Many thanks Joost,

Ronald

[Joost Ink]

your welcome
max has issues with high coordinate numbers, has to do with the fact that max rounds numbers off to a certain ratio.
Also cam movements etc. struggle with this problem, so I guess Vray has the same.
Because of this i allways use a local origin when importing to max in the left bottom corner, so you never have negative coordinates.
glad it solved your problem.

[zeilveen]

Many thanks, completely gone now!

I have had the camera problem before but didnt think of this when working with Vray.

This is why the forum can be so important here, tunnel vision gets solved almost right away, thanks Joost!

Ronald