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Vray noise in reflections
show user profile  3joez
I'm sure everyone is rolling his eyes, knowing the absurd number of post that exist about this matter.
But this time I'm really stuck.
I've tried every combination know to man about minimum samples (till 64!!!!!), dmc subdivisions, noise (i've evene tried 0) and you know, all others Vray parameters.
The fact persist even with GI turned off.

Here's the situation. The problem resides in the light bulbs (vray sphere, 30 mm diameter) put inside the wall. Light passing through a shelled glass. Their reflections causes this:
I don't want subpixel map on because it ruins my hilights (and still, it doesn't solve the problem, though it's slightly better).
Maybe I shall surrender and use a simpler setup just vray light material, even though I hate it.

Photobucket

read 5743 times
5/26/2013 4:09:57 PM (last edit: 5/26/2013 4:14:37 PM)
show user profile  herfst1
Ha, just red an article on this about 30 mins ago.
http://3dlight.blogspot.com/


To condense the advise, try upping the light samples of your vraylight. Also try upping the reflection samples of your floor material. Once you have an alright result up the dmc samples a touch and reduce the noise (in the dmc rollout) to something like 0.005.

[edit] though I don't understand the article when it says to set the Adaptive Amount to 1. Is that max and min?
read 5735 times
5/26/2013 5:02:18 PM (last edit: 5/26/2013 5:04:37 PM)
show user profile  DannyMax
Why not just use a spotlight and place it just below the light , I'm sure it would render faster too.anyway I hope you sort it out dude I know these sort of things can be a real git to sort out lol




read 5730 times
5/26/2013 5:06:35 PM (last edit: 5/26/2013 5:06:35 PM)
show user profile  Error404
try clamping the output in the color mapping to something like 5 or 6? See if that helps


That does seem like a complicated way to get a white dot in the ceiling. If you want a pattern on the floor/wall from the lights, I'd use an IES light.

If you want to stick with this approach, you may need to try lowering the reflection cutoff threshold of your floor shader, both your shaders (and possibly the shaders on your objects making up your light geo as well) and lowering the cutoff threshold on the light itself. And giving the light more subdivs. It probably won't be worth it in the end though.

www.DanielBuck.net - www.DNSFail.com

read 5723 times
5/26/2013 5:28:55 PM (last edit: 5/26/2013 5:37:01 PM)
show user profile  Garp
Your shelled glass is the likely culprit (and overkill, unless you plan some close-ups).
Those dots don't look like noise to me. More like the light rays bouncing many times inside the glass.




read 5722 times
5/26/2013 5:29:55 PM (last edit: 5/26/2013 5:34:17 PM)
show user profile  3joez
No Garp, that doesn't change the situation.
@Error: IES behave very similarly to original lights. Letting the clamp off, didn't do the trick, either.
I may try with spotlights now.
@Herfst: I've tried ridiculous subdivision number I'm not even saying how high (it's better but not perfect and rendertimes are biblical).

Photobucket

read 5707 times
5/26/2013 6:03:53 PM (last edit: 5/26/2013 6:03:53 PM)
show user profile  herfst1
Why not try make all those lights using just one large vraylight covering the whole roof and positioned slightly above it, and screw the insides of the bulbs, just make them holes? Might be easier to control all the settings. Then again, I'm not sure if there will be a light leak problem doing it that way, might have to exclude the roof from illumination or something.
read 5707 times
5/26/2013 6:16:55 PM (last edit: 5/26/2013 6:16:55 PM)
show user profile  Bolteon
Okay... First off; if you're going to post up complaining about noise, please don't include a jog that's been so compressed that noise is everywhere in the image.

Use techsmiths' jing instead.


Secondly, to do what you're wanting is a problematic situation since anything completely setup via physical systems is render intensive even for a well tuned machine like vray.

Third, you're going to want accurate glass ior (1.45), appropriate thickness to the glass and a proper build inside the light bulb encasement to get the right sort of...

Caustics.

Yup, gonna need them.

There's so much that goes into setting up a scene like this to be physically accurate that its way too long to describe in a post as I'm laying in bed on vacation in Italy. That being said, I'm a huge fan of making the software do its job and expecting the hardware to keep up but in the mean time if you need this done soon, it might be a good idea to fake it.

I'd be happy to help out next week when I'm back home though if it can wait a little.

-Marko Mandaric



read 5687 times
5/26/2013 10:08:03 PM (last edit: 5/26/2013 10:08:03 PM)
show user profile  donvella
duplicate the light geometry - we call this one light2

light1 - set object settings so it doesnt cause reflections/refractions - or render it on its own layer so you can layer in in post - this pass should not cause any light refractions on any object (like a matte pass)

light2 - reduce the light intensity until desired effect

In vray i tend to usually duplicate 'key lights' and seperate the specular from the direct (in advanced rollout). This enables you to have low intensity speculars.




read 5663 times
5/27/2013 4:28:50 AM (last edit: 5/27/2013 4:28:50 AM)
show user profile  3joez
Thanks Marko. If you are near Venice, where I stay, I'll owe you a beer.
@Donvella: very good idea...I might try it.
Photobucket

read 5651 times
5/27/2013 8:17:27 AM (last edit: 5/27/2013 8:17:27 AM)
show user profile  Error404
donvella:

you can simply lower the specular contribution on a light, you don't have to duplicate it :)

And in maya (I can't remember if this is possible in Max or not) you can use override shaders on the shading group. You could put a light material that is much darker in the reflection override. So reflections will see the dimmer shader.


3joez:

what is your cutoffthreshold and subdivisions on the lights and shaders?

www.DanielBuck.net - www.DNSFail.com

read 5640 times
5/27/2013 5:50:34 PM (last edit: 5/27/2013 5:51:37 PM)
show user profile  BishBashRoss
"you can simply lower the specular contribution on a light, you don't have to duplicate it"

Thanks for this tip Error, I did not know this!

I just had a look now and found diffuse multiplier in Vray light properties. Is this what you are referring to?

Thanks!





read 5631 times
5/27/2013 6:56:18 PM (last edit: 5/27/2013 6:56:18 PM)
show user profile  Error404
yea, there should be a diffuse mult, and a spec mult

www.DanielBuck.net - www.DNSFail.com

read 5630 times
5/27/2013 7:10:20 PM (last edit: 5/27/2013 7:10:20 PM)
show user profile  BishBashRoss
Just tested it and it doesn't work. Looks like the option I found controls something else. Hmm, stumped.





read 5625 times
5/27/2013 7:19:43 PM (last edit: 5/27/2013 7:19:43 PM)
show user profile  donvella
>So reflections will see the dimmer shader.

This requires you to change each material in the scene. Easier to duplicate the light for everything yeah (only 1 step)?

I must have an old vray, I dont have a seperate specular control (care to post a screenshot of what this looks like?). And the method is easy to understand and apply - thats good for 3d generally





read 5612 times
5/28/2013 12:32:08 AM (last edit: 5/28/2013 12:59:57 AM)
 
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