What could be causing these Black Splotches?

[MegaPixel]

http://www.cgvisions.com/temp/black_splotchess.jpg

The above image was rendered using DR. This is my first heavy scene with Vray and I still have alot to learn about Materials and Light usage within Vray. I'm trying to figure out what could be causing the black artifacts that you see mostly on the ceiling and floor?

I am also encountering some Material Overbright messages in my Log and was wondering if it could be related to this? I have lots of Glossies, I also have my Overlapping Faces threshold set to .002 and I am not using Caustics.

Thanks for any help in advance - Mega

[Candelero]

Camera Corrections ?

[MegaPixel]

No Camera Corrections - I noticed that the log would flag warnings if I used any camera modifiers so I've stopped using them in my Vray scenes.

I have a hunch (and who am I to have a hunch being so new to this...) that there is some kind of material or light in the scene causing this? But how to efficiently troubleshoot it?

Mega

[Candelero]

Check out the first warning - it will tell you from which object the problems starts. Then check the material .

BTW, have you rendered it with an Override pure Gray material ?
Any problems there ?


Best regards,
nikki Candelero

[MegaPixel]

http://www.cgvisions.com/temp/black_splotchess_2.jpg

This image new was rendered out the night before the one posted up top. This was a DR render where my slaves couldn't see all of my texture files so they kind of rendered out white. The shaders were still rendering and as you can see, these black splotchess appeared here also. Don't know if that helps, but to answer your question, no I have not rendered this room out with an Overide material yet. I'll try to do that later this afternoon.

I can't get this scene to render fast enough for testing purposes without using DR. Will disabling AA help that much? BTW Candelero, this shot is from the same scene file you have been working with from a previous tech support post.

Anyhow, thanks again for the quick responses. I'll take another look at this - Megapixel

[vlado]

Do you have any standard materials in your scene? E.g. with Oren-Nayar-Blinn shader?

Best regards,
Vlado

[Candelero]

Any Falloff maps with Fresnel option in it - e.g. reflections etc. ?
Mind to check the Override IOR check box - is it ON or OFF ?

Best regards,
nikki Candelero

[MegaPixel]

I tried hard to use all Vray materials. I also used the right click menu feature to convert the scene to a Vray Scene so I don't think there are any Standard materials left.

In the Kitchen, I am using a Falloff map on the Chair Cushions but I am using the perpandicular viewing angle - not fresnel. Was trying to simulate a kind of velvet but it didn't work to great anyhow This is a toughy huh?

Thx - Mega

[MegaPixel]

Sorry it's taking so long - Had some office work to do. I'm waiting very impatiently for this scene to render with a basic grey material overide on it. I'll get it posted when it finishes.

Question: Even if Caustics were enabled in the Vray light properties, as long as the check box in the render dialogue is unchecked, they shouldn't be casting anything right? I discovered that half of my scene lights were this way after finding the vray lights properties box in the vray system menu.

[tricky]

I seem to get something quite similar to this in my images. Its usually on reflective cirved metal cadding. I've tried quite a few things to no avail, so just end up touching them black bits up in photoshop.

BTW, do you use HDRs? That could be a thing causing it perhaps?

Sample below:
[img]/images/black dots.jpg[/img]

[MegaPixel]

Ok here is the Material Overide Render I did last night with low settings and no AA. I see no black artifacts.

http://www.cgvisions.com/temp/kitche...veride_low.jpg

Soooo... I guess that means that the problem is most likely related to a material in the scene and not a light source right? I do have alot of glossy type materials in the kitchen and a few metallic type amterials around the appliances - I wouldn't know where to begin as far as hunting down the problematic material goes though. Alot of my materials have been merged in from varius scenes I've been able to secure - most likely from different versions of Vray. Any foreseen issues there?

Tricky - No I havn't explored the wonderful world of HDR's yet, maybe someday in the near future.

MegaPixel

[meanadam]

Maybe white 255 in a falloff somewhere? Or bump map? I tend to get lazy and loose a white somewhere in some material.

[DaForce]

Easiest way to check if there are any standard materials in the scene.. open the material editor and click on the first button across the bottom on the left.
Then click on "scene" and you should see a list of all the material in your scene. If there are any standard materials convert them yourself.
And any materials using a falloff map.. such as the velvet, try replace just those with a default gray.

Then render.

[harperperkins]

Dave, another thing...I love how much you're a stickler for details putting all that finish work geometry in your scenes, but be sure (and I'm pretty sure you do) you've got these things on their own layers. You can selectively turn things on and off so your test renders won't take so long. It'll also help you corner those problem spots a little easier.

This is going to be a great scene when you get it finished!

Matt

[MegaPixel]

So are you guys saying Not to use falloff at all? or is it only the Fresnel type that is buggy? Because I DO have falloffs in a few places but I've switched them to perpendicular/away type.

What I'd like to know, is how come some of this stuff which was merged from a purchased evermotion arch-interiors collection setup specifically for Vray, is now not supposed to work? These guys tend to have large amounts of materials with falloff and fresnel effects. Is this a Vray version thing and if so, should I be switchign versions?

Harper (Matt),

I've got a fairly elaborate Grouping and Layering process for the scene but my biggest problem right now, is getting acceptable test render speed. Even with a few objects shown and material overide, I waste alot of time.