Vray Atrium, help!

[aflack]

I really need some help! I got Vray a couple of weeks ago and have been working on some animations and stills from a hospital atrium. The image below is pretty much the last image from the animation which I also making a still from.

 

I am happy with the entire image, except the underside of the roof. It doesn't seem to matter how high I set the settings for Irr Map (first bounce) and light map (second bounce), they still look pretty blotchy.

 

I have been messing round with this now for days and don't seem to be getting anywhere. It seems to me the underside isn't getting enough bounces of light!

 

Obviously any other critism would be great as well.

 

Any help would be great thanks.

[Trick]

If you choose not to use a filter in the Lightmap you can check "prefilter" to smooth it. You can also use the "nearest" filter to prevent artifacts. "Prefilter" is only done once, "nearest" is constantly checking sample spacing. This only works when Lightmap is your secondary bounce...

 

Maybe a stupid question: do you have any noise map in your material?

[aflack]

No there is no noise in my maps!

 

Thanks for your help, I'll give it a try and see what I get!

[skogskalle]

Dont know whats causing the blotches, but I compared your settings to the settings I used in a scene some time ago (that rendered blotch-free)... you have the IRR-map interpolation type set to "weighted average", mine was set to "Least square fit".

And your lightmap Sample Size was set to 1.0 m world scale, while mine was 0.02 screen scale....

 

again, dont know why your settings would cause blotches, but feel free to try mine. I believe you could lower the lightmap subdivs to somewhere between 600 and 1000 too....

 

btw - is the material on the blotchy object a Vray material? sometimes standard max materials cause some bad GI effects...

[aflack]

I tried adding a prefilter and setting the filter to Nearest and it has made it a lot better but as in its not blotchy anymore which I guess was the original problem but there are still I think you call them artifacts where that flat ceiling butts up against the wall. I've tried pretty much everything now but can't get it to make a difference.

 

Thanks Skogskaille I'll give your setting a try over night.

 

I now have a new problem though, it doesn't matter what-ever setting I set the Irradiance map at whether it be Very Low or Very High it still renders with 5 passes, obviously this takes a lot longer and I want it to render much quicker. Anyone got any ideas, I've tried going back and checking everything I've changed but I can't seem to find anything.

 

Thanks for your help.

[Tim Nelson]

I think those extra passes might be coming from using interpolation in your materials. I don't fully understand how that works, but when you use reflection interpolation for any materials, you will always end up with more passes, depending on the interpolation settings.

 

For that reason I always avoid interpolation and always keep my number of samples really low.

 

For lightmap filtering, I've always found that 'fixed' filter works pretty good for me at about .02. Then I turn on pre-filter to about 50.

 

Another big thing that you should try is to raise your interp. samples in your irradience map settings. Try raising it to about 30-35 to see if it helps. I don't think it increases rendering times, just smooths the light solution out a bit. Too low and you get a lot of splotches, too high and you start losing detail. 30 should help a lot though. With that, you might even be able to lower your irmap settings a bit to quicken rendering times.

[Trick]

Before you go any further you first have to be sure where the artifacts come from by setting the Lightmap off. If you still see intermittent lighting artifacts you have to dial up your HSphere subdivs and find a balance between rendertime and accuracy by changing the interpolation samples.

 

You can also try to set preset to custom and start with:

min rate -5

max rate -2

color and normal threshold to 0.25

and distance threshold to 0.1

 

By varying min/max rate between -5/-2 and -3/0 and dist.threshold between 0.1 and 0.5 you can see if this makes a difference.

 

When testing the first bounce be sure to set the multiplier between 0.5 and 1 HIGHER so you can see what parameter are doing. Render the affected region only...

[RyanSpaulding]

Lightly greyed out people >>>>>>>>>>>>>>>> Using the colored bitmaps

 

IMO, inserting full color cutouts of people/cars ruins an image to me unless it is lit perfectly. I like this look tho. You get a sense of perspective and height w/o the CRAP.

[aflack]

Thanks for your help Tim and Trick, you advice finally helped me solve the problem this morning. It was basically bad geometry, I don't know why but when I remodelled it in a different way it now renders much better. I turned off the Light Map and it still did it, so I changed all the Irradiance Map setting that you suggested and it made no difference so I thought it could only be the geometry.

 

You were also right about the interpolation in the materials Tim, once I turned that off it goes back to rendering in the number of passes you set.

 

I've attached some of the stills from the animation that I rendered overnight as you can see the artifacts are still there so I'm going to try and render a few frames today before the weekend and make sure the problem has gone away for good.

 

Last problem with this animation is how to make the textures stop flickereing?

 

I really want to thank you, I only brought vray a couple of weeks ago and I feel like this has all been a crash course in it, but I feel a lot more comfortable with it now and understand how to control the lighting much better!

[Tim Nelson]

Glad you found your problem. Show us the animation when you can.

 

Flickering in animations with Vray has always been synonymous with authorization issues. But since you said you bought it, maybe you should just contact the Chaos team to get it re-authorized. If thats not the problem, then post a thread over at the Vray forum & I'm sure you'll get some help there.

 

Since I haven't done a lot of animation in Vray, I don't know of any other ideas to fix that.

 

Good luck & show us when you're done!

[RyanSpaulding]

Can you render off individual images and string them together in a movie editing program? If it can do the individual images fine, I'd go that way. You have to piece it together, but that may prevent VRay/Max from messing it up.

 

But I dont have VRay so I dont know the issue. Just a thought.

[aflack]

Well I finished the animation and images. I've attached two images below but I don't have anywhere to store an animation on-line so I'm afraid I can't show you.

 

I solved the problemn of the flickering textures and the artifacts around the ceiling area. It was basically because I was using Lightmap as my second bounce, I assume it was because I didn't have enough samples but if I set samples above 1400 then Max crashed and I again assume for a space this size I would need a lot more. So I just used Quasi as my second bounce and although it took ages to render at least it solved all the problems.

[IC]

They look great for animation stills.

What do you do with the ghosted figures when animating?

[neil poppleton]

i would be interested in the render time (plus image size) for each frame of your animation and how many machines you could render on ?

[aflack]

Those images were just stills from the animation rendered at a larger size and then I added a few people, the main animation doesn't have people in. If I could render it again which I may do I think I would just add frosted 2D cardboard cut-outs in. I don't think it would detract from the animation too much but it would give it a better sense of scale. Any opinions, how do you huys deal with people? I have always tended to go for frosted people either black or white.

 

The stills are 640 x 420 they varied in time from 15 minutes a frame to an hour a frame. I have Max installed on about 40 machines through-out the office they range from Pentium 4 3.1Ghz with 2Gb of Ram down to Pentium 4 1.8Ghz with 512mb of Ram. I know the render times are long but that was mainly because of the blurred reflection on the floor which I thought really made the stills better.

 

Also I had to set the Irradiance Map quality to High because I wanted to include some plants in the model. At lower quality and at a distance the plants really flickered badly so I had to take the quality right up. Any body else come up with a better solution.

 

I've attached some more stills.

 

Of course any suggestions on how to make them better would be great. I was trying to achieve a late summer evening mood when the hospital might be empty.

[aflack]

Final two.