Black Splotches

[ShaunDon]

Hey guys. I'm trying to churn this image out and get it rendering overnight, but I'm coming up with black splotches as seen here:



I've searched the boards since I'm sure this is a common problem, and Vlado suggested one person turn off "limit search range" in the irradiance map parameters -- but I can't find that check box in my settings (VRay Adv 1.09.03m). Can anyone help? Thanks!

ShaunDon

[percydaman]

limit search range is only in the latest build.

[ShaunDon]

Dammit. Of course I'd find this out working on the weekend while the boss isn't here. Anyone know of any other way to kill these kinds of glitches? I'm trying to get in touch with him to get our access information so I can download the latest build, but I'd like to be safe...

Thanks!

ShaunDon

[tom schuelke]

Hi ShaunDon

do you use fake highlights together with anisotropic reflections somewhere ?

look at the bugsection

http://www.chaoticdimension.com/foru...d668c8d301b390

seems to be a bug if this is your problem.

had the same. if it is so just turn of anisotrophic. this should solve it so far.

good luck,

Tom

[ShaunDon]

Nope, no anistropic reflections... just standard reflections with the vray material with fresnel turned on. I guess I don't have any more time to troubleshoot this issue, so I'll have to just clean it up in Photoshop on Monday. Thanks for your help, Tom!

Shaun

[ShaunDon]

Comrades --

Here's a low-res version of the render I got out of Vray this weekend. I've highlighted the especially troubled spots, though you'll notice there were quite a few incidents. I'm now on a quest to fix these splotches as they were horrendously painful to Photoshop out and my time in post is usually better spent improving the image rather than restoring it... so:

The only two different things that I did in this scene that I'd not previously done were --

a) used VrayShadow for all interior, photometric lights.

b) reduced all reflective materials to depth of 1 for speed... also used reflectivity a lot more in the laminate materials for added detail and CG-sheik...

The splotches are especially bad where reflective geometry intersected or reflected one another to a great extent. I turned up the depth to 2 and rendered again. They reduced in some areas noticably, in others not so much.

So is that the problem? I really don't want to up the bounces to 5 again, since I know the increased render times will force me to kill the reflections when I'm in a crunch.

What about installing the beta for 1.5? Is it possible that I might have better luck with that? We're still on max 4.2 until 1.5 goes final, since I know DR support for 6 hasn't been finished yet -- is DR non-functional only in max 6, or has it not been implemented at all in 1.5 yet? If we can use the 1.5 beta with 4.2 and still have distributive rendering, it might be worthwhile for us to start using it.

Thanks everyone!

Shaun

[vlado]

Looks to me like you have overlapping faces in those areas, maybe that's the reason for the black spots.

Best regards,
Vlado

[ShaunDon]

I'll check again. The hand-off counters definitely run into the teller towers, but I modeled the whole scene from scratch...

Also, not sure this is important but I rendered the teller line separately from it's own scene after modeling it, with all the same materials, and I didn't have any problems with it. Maybe that nixes my "self-reflection" theory.

Shaun

[TRGraphics]

I had the same problem with a scene the other day. I checked everything without finding a problem with modeling or materials. I finally just merged everything into a new file and the problem went away. Don't no why.

Tony

[ShaunDon]

That helped a lot from what I can see now of my new render progress. Thanks Tony, that should have been one of my first things to try. It's still splotching, a lot more intensively in places that it didn't show up before. Now I'm even more puzzled.

Shaun

[Mirko]

I had the same problem last week. I had black splotches on the ground as well as in a vehicle in an exterior scene.
I found out, that the vehicle had a few vertices which have not been melted together (I do not know the correct english translation for that but I think you know what I mean). After melting these vertices, the splotches have been gone (in the whole scene!).

So I think it seems to be always a matter of geometry problems. Just check your whole scene for unmelted or isolated vertices.

Regards,
Mirko

[ShaunDon]

These are identical regions from two scenes, the second one being a straight re-merge of the first scene. You can see the left side is much improved, but the right is identical... as is the case in the rest of the image. Some splotches disappeared or reduced greatly, others didn't change at all.

I'll try re-welding elements in the scene, but I'm in the unfortunate position of having already turned this job in and now onto the next one... I'll pray that this was a one-time thing, but it makes me nervous. And I'm really not sure where the modeling could have gone wrong, it's pretty much straight up box modeling and profile extrusions. Couple of closed lofts with a cap holes modifier... as far as what I normally do, this was pretty simple.

But if you're right and it's the geometry, maybe I'll luck out on the next run.

What about my earlier question about DR in Vray 1.5? I should probably know this, but can anyone speak to if DR is enabled and just not compatible in max 6, or is there no DR in the 1.5 beta at all as of yet?

Thanks guys!

Shaun

[mukks]

try this one...

turn off shadows n render

[ShaunDon]

Oh Crap! Not my VrayShadows! Will do as soon as I get the chance. Thanks dude.