No AA in refelctions / Bumpmaps cause noise

[Sopho]

Hello,

finally i got here. My first post
While doing a few renderings i encountered two problems i wasn't able to solve:

1) Studiolighting setup with 3 Vray-plane-area lights, Irrmap for frist bounce, LC second. When i have reflective materials like chrom (IOR 16) the arealights are not antialiased, while everything else is. I tryed differenet things, like changing the imagesampler, trying out differnent AA-filters (which sometimes helps a bit) and pushing the subdivs in the lights. But overall i wasn't able to get a good solution (by remaining low rendertimes). Any ideas?

2) Maybe a bit more tricky: Same setup as above. I have a concret wall, with a highres texture in the diffuse channel. The same texture is also in the reflection channel (in a fresnel fallofmap) and in the bumpmap channel. When rendering i get a enormous amount of noise which is produced by the Irradiance map in combination with the bumpmap.
Only turning off the bumpmap helps to get rid of the noise.
I tryed different stuff like pushing the Hsph value and area-lights subdivs, setting the irradiancemap to an overall high preset and changing the different threshold options in the Irrmap. When pushing everything to high the situation gets better, but it's definitely no solution 'cos of the increased rendertime.
Any ideas?

Hope you can help me... Maybe i should post pics...

Thanks anyway,
Sopho

[Da_elf]

can we see some settings. the 1st problem sounds like your light is really bright and therefore you might need to use something like sub-pixel mapping (i think thats the name of the option. sometimes i dont look at the names anymore hehe)

[joconnell]

Definitely post some pics. For the area lights, try turning on clamp output in your color mapping rollout - admittedly this will stop you using floating point colour though.

For the concrete map, it might be too high detailed for the bump map and be causing a lot of noise in your reflections - try turning down the bump amount and maybe blurring the copy of the concrete map in the reflection channel - the tiny detail mighn't give you the result you're looking for anyway.

Definitely post some pics so we can see where the problems lie and what you're trying to achieve.

[Sopho]

pics

okay.. lets start with a bunch of pics for my second probelm:

Here you see a concret wall. Reflect- and diffusechannel have the same map applied (instance).
www.sophokless.de/Material/shorttrick.jpg
Looks quite okay.

Now lets try to turn the bummap on. It's the same texture, instance of course.
www.sophokless.de/Material/shorttricknoise.jpg
Looks great, eh?
Lets check the rawGI renderelements:
www.sophokless.de/Material/shorttrickGInoise.jpg
The problem obviously seems to be related to this channel - beeing a product of the irradiance map.

Here're my settings:
www.sophokless.de/Material/settings1.jpg
www.sophokless.de/Material/settings2.jpg
www.sophokless.de/Material/settings3.jpg

Thanks

btw: in the upper left of the first pic you see a bit of the un-antialiased area light.

[percydaman]

your Hsph subdivs are quite low. try raising them back to 60 and see what that does. raise it more if needed. Raise the interp samples a little bit as well. try back to 30.

[Sopho]

I already tryed stuff like this before, but the situation is not really better. Have a look here - just the RAW GI:
www.sophokless.de/Material/shorttrickGIHigh.jpg
(Hsph = 60, Interp. = 30)

UPDATE:
+ Inreasing the blur effekt on the reflectionmap map didn't work.
+ Decreasing the bumpmap from 24 to 5 was better.. but not perfect, i would have to go down to zero to have a perfekt look.... but wait... then i wound't have any bump effect. See here bump of 5:
www.sophokless.de/Material/shorttrickbumpof5.jpg

[joconnell]

I'd say the concrete map is too finely detailed to work as a bump map - there's tonnes of 1 pixel details in it so you're getting tiny white pixels beside black pixels in the bump map - this is causing you to get some 1 pixel extremely bumpy and reflective bits right beside some black bits with no bump and no reflection so it's appearing as loads of tiny little specs of heavy reflection - almost as if the really reflective bits are getting a full reflection of your area lights at the side.

What I'd recommend is to turn down the bump a bit, and then bring your concrete map into photoshop and use levels until you only have pure white for the wall and then tiny bits of black for the dents and cracks - Load this into your reflection channel. Alternatively use the blur controls in the bitmap mapping controls. This will admittedly have less variation but solve the problems. Because of the tiny tiny variations in the concrete map, it's as if you were using the photoshop noise and grain to make an image and using that as a reflection map.

[joconnell]

Oh and a lot of people in pixar don't bother with bump maps - the use the reflection channel instead with no bump as it breaks up the highlight and gives them the look they want. not saying you should, just as an aside.

What would happen if you just use the bump map and no reflection map? It's pretty much going to average out into a 50% grey anyway...

[Sopho]

Your solution to my problem is quite obvious, but i didn't even think about using the levels command in PS, 'cos it was so grey... :P

so.. lets get back to my first problem: The unantialiased Vray lights in my refelctions.
I stick with a linear workflow, so "clamp out" won't work for me. Da_elf mentioned sub-pixel mapping - can someone explain that to me in short terms or post a link with more info on that?
I rendered a animation with the scene above and the unantialiased lights flicker like hell on the chrome faucets

Thanks for the help

[dlparisi]

Unless you're adjusting it in post you can still use LWF and select clamp output. Your final image won't be in float values however.

For sub pixel mapping see http://www.spot3d.com/vray/help/150R...lormapping.htm