V-Ray flickering issue

[Imagine This 3d]

Hi all. I'm just trying to create a basic walk-through of an interior with 3ds Max and V-Ray and I'm having all sorts of problems with flickering reflections. I've posted an example movie on youtube:

 

http://www.youtube.com/watch?v=QQdjOgLyqRA&feature=g-upl&context=G25b953cAUAAAAAAAAAA

 

My settings can be seen here:

http://imaginethis3d.com.au/wp-content/uploads/2012/01/vray-settings.jpg

http://imaginethis3d.com.au/wp-content/uploads/2012/01/glossy-materials.jpg

 

The problem is particularly visible in the glass beside the staircase and in the glossy black kitchen cupboards.

 

Any suggestions would be much appreciated.

[Corey Beaulieu]

Nothing really stands out as an issue. The first thing to think with flicker is geometry, either tha part that flickers or a piece being reflected, but it doesnt look like that type.

 

A few things to try:

 

Check sub pixel mapping on in your color mapping and clamping too.

Try using the adaptive DMV sampler with a min of 1 and max of 4. Maybe this will be cleaner if not just a different result.

Switch to screen scale in your light cache withe a sample size of 0.002 (default) this will even out your light cache sampling

And if there aren't already, add a few skylight portals to make sure your exterior lighting is coming in cleanly.

 

Your materials look fine. I would usually check fresnel for glass but it looks fine in your render. The black doesn't matter because reflection is off.

 

Last thing, with a pre calculated IR and Light Cache, you need to redo these every time you change geometry, light settings, and object placement. You can also run your light cache as fly through with your IR pass and then only use the IR from file. Leave secondary as none. Your light cache will store in the irradience map. If all else fails, try brute force with same light cache and a subdiv of 12 or 16. It will be noisier but accurate.

 

Good luck.

[Imagine This 3d]

Thanks Corey, good suggestions. I've incorporated most of them and the result seems to be a big improvement. Your suggestion about baking the light cache into the irradience map is interesting, although wouldn't this mean I would have to render every frame for the pre-calculation (I'm currently rendering every 10th frame for the irradience map)? By the way I've been following the following tutorial for my walk-though setup thus far:

 

http://www.spot3d.com/vray/help/150SP1/tutorials_imap2.htm

 

Cheers

Tim

[Corey Beaulieu]

I'm glad I could help.

 

Rendering the light cache in flythrough mode means that it accounts for every frame in one file at frame 0 so it will appear very distorted and blury, but this is corrected. I know that most of not all tutorials suggest the separate calculation of irradiance and light cache, but I've always done is and never had a problem. A teacher suggested it, I doubted it, but it works. I only wish I knew why exactly.

 

As to the every 10th frame. That's a good number. You kinda choose that based on your camera move. If its moving fast and objects are appearing and disappearing more often than every 10th frame then you may need more. Likewise, if the camera is slow and everything is in frame from the beginning then you can do less, like every 24th or more. It's a trade off, time for exactness.

 

Did the flickering go away?

[Imagine This 3d]

Yeah, the flickering is pretty good now - thanks for your help. I'll try the light cache and irradience map at the same time now and let you know how I go. Thanks again!