Can't get rid of volumetric banding

[luckbat]

Hello, all.

 

I'm in the early stages of modeling a set for a short piece I'm working on, but I'm getting some strange artifacts that I can't seem to shake.

 

I based my volumetric settings on this thread ( http://www.hash.com/forums/index.php?showtopic=3994 ), but I don't seem to be getting the same quality of render.

 

Number one issue is the sharp diagonal banding on the light shaft. I've set my klieg width to zero, as instructed, but no dice. It's not the "quality" setting in the volumetrics, either--even at 99999%, the banding is as sharp as ever.

 

Number two is the missing shadows behind the urinal pipes. What happened to them? Is it because of the Z-buffer? They show up properly when I switch to Raytraced, but then the edges of the sunlit square on the wall turn hard instead of soft like they should be.

 

I gotta say, I'm confused. I downloaded the project in the thread listed above, and it's got nice soft shafts of light, even though all the lighting settings are the same as in mine.

 

Are there any volumetrics experts out there? I've been toggling the lighting properties for three straight days and I just can't get this ray any softer. Even with multipass-16 and depth of field! Can anyone spot something I've missed?

[KenH]

Isn't there a second "softness" option (under the shadow settings" to adjust the shadow softness? Did you try that?

[luckbat]

Isn't there a second "softness" option (under the shadow settings" to adjust the shadow softness? Did you try that?

 

Whoops.

 

I tried setting the percentage higher to try to get rid of the banding (it had no effect), but I never thought of setting it lower to get the shadows back.

 

Well what do you know? There they are!

 

Unfortunately... Setting the softness to zero makes all the shadows hard, including the edge of the sunlit square on the wall. I guess this is just a limitation of Z-buffered shadows. Obviously, the sunlit square should have soft edges, while the pipes, mere centimeters from the wall, should have hard shadows.

 

Switching the klieg to raytraced shadows with multiple rays would, of course, render all this stuff properly, but I was really hoping to avoid the resulting render slowdown. Especially since the volumetrics project listed below doesn't seem to need them.

 

The banding... it taunts me...

[luckbat]

Hey, wait a minute...

 

This excerpt from the lighting properties page in Hash's HTML Help sounds like exactly what I want:

 

http://www.hash.com/htmlHelp/v11.0/GeneratedHtml/LightP.htm

 

Fall-Off Softness

Visible: Sometimes, Default: 80%, Min: 0%, Max: 100%, Percentage

This setting is only used when a object is set to be volumetric. Changes how smoothly a light falls off to the background color. A value of 0 causes an abrupt edge where the object falls off to the background color. Higher values soften the edge caused by the falloff.

 

There's just one problem: My light objects don't have a "Fall-Off Softness" property! Do yours?

 

How can I access this setting?

[WillP]

Tools->Options->Show Advanced Propeties

[heyvern]

Don't know what you think of this idea...

 

If you like what you have with the volumetric light but want a harder shadow behind the pipes you could use another light that only casts shadows and put it in the light list for the urinals.

 

Constrain this light to the volumetric light and you can "fake" the shadows on the pipes... not really sure this would work actually... would the light from the volumetric blow out the shadows from the second light? You might be able to make the shadows darker on the second light to compensate.

 

Just an idea....

 

...dagnabbit... now I have to pee....

 

Vernon "!" Zehr

[luckbat]

Man, oh man! I think this bathroom is haunted. How else to explain the bizarre "ghost doors" that show up in the multipass render?

 

The doors are, of course, present in the geometry, and they show up fine in the preview renders, but when I do a render-to-file using the same settings, they disappear! Watching the 16-pass render, I observed even further strangeness. In the first few passes, the doors were absent. But by the halfway point, they started showing up, yielding the transparent doors you see before you.

 

Needless to say, the doors are not set to transparent, and as I mentioned they show up normally in the preview renders. Has this ever happened to anyone else? I'm using the MacOSX 11.1 beta, but the same thing happened when I rendered using 10.5r.

 

Meanwhile, I was quite disappointed to see that even with raytracing set to 8 rays, the sunlit areas (I've added a second window since the previous screenshot) have no softness whatsoever! I thought that was the whole point of having multiple rays...? Help me, Yves Kenobi! You're my only hope!

 

Needless to say, I'm still getting hard lines on the volumetrics, no matter what softness settings I use. Even 8-ray raytracing had no effect. What must I do? At this point, I'm just going to have to throw in the towel and fake everything like Vern suggested. Heck, I might even burn the shadows into the wall texture or something. This is getting ridiculous.

[luckbat]

Tools->Options->Show Advanced Propeties

 

I tried turning on the advanced properties, which revealed every advanced light setting except "Fall-Off Softness," the one I wanted. Honest! Check out my screengrab.

 

One more day of this, and I'm going back to posting everything in the New Users forum, where I obviously belong.

[filipmun]

My idea is not a solution but a work around, I don't use volume effects, in fact I fake it by building a model to mimic the volume light with transperency and noise.

 

I have lost a great deal time perfecting these settings but still did not get the results I hope for, so I work around it. Since then, I have been faking geometrcal structure with image map too and the result is quality visuals with eficiency.

 

Well this is because I can paint better then doing maths.