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Mental Ray - black blobs help


derijones
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Hi folks

Attached is a WIP of a new building - textured in Maya, rendered in Mental Ray with a HDRI dome and one simple area light for sun - Final Gather (800 rays) setting only (no GI). I keep getting these random black splodges - I can't see any connection with geometry. The FG previz doesn't appear to have any holes - only when it's doing it's final run do the holes appear.

Anybody got any ideas why this is happening or how to solve it?

Thanks

Deri (tearing his hair out!)

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It could be a material problem. i have these problems in max using the raytrace material, sometimes even with the standard material. i solved it using the DGS-Material even for plain diffuse materials...

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Thanks - I'll try that. I'm using Photoshop texture file nodes for convenience (does MAX have that? - colour, bump etc on different layers - very handy!) and I wonder if that might be a cause - I rendered the second example again later and it came through without a problem.....

Thanks again

Deri

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  • 4 weeks later...

some say its the material that causes the prob, for some its the render settings, as for me, i say its the mesh...try to convert everything into an editable poly, let's see. it happened to me, i tried everything, but turning it into a poly worked for me.

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Bloody Hell?? Let me know if anyone found an answer...

 

What has been tried to solve it?

- additional RAM?

- other materials?

- other type of material?

- different type of lighting?

- more rays? more photons? higher FG?

- Raytrace Depth?

- Perfume?

- Killer Rabbit?

- Vanessa Fembot?

 

nisus

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The more and more different answers I see make it look like a memory bug to me. I bet if I consolidate modifier stacks and trim down some textures the black spots go away - will let you all know in 30 mins.

 

Scene Stats

 

Objects: 85

Faces: 397333

Memory Used: P:909.6M V:941.3M

 

Lights: 6

Shadow Mapped:0

Ray Traced:1

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no skydome and all was well untill an just over an hour ago. Bizarrley when i go backwards the black blobs are still there.

 

All lights use inverse square Attenuation - 4 fill lights and one shadow caster IK'd to a daylight system that is turned off!

 

At the moment I am welding vertices on all objects - lets see how I get on.

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I have deleted the fill lights and the blobs have gone. Mental Ray is a schizophrenic twisted cantankerous son of a female dog.

 

Yes it is..... but so is tuning a formula one car ;)

 

In your last post, with the fg turned off, where the fill lights on?

 

If you want, strip the geometry from the scene, zip the file up and post it. I'd like to take a look see. If your running Mac export for PC, if possible. I've run into some situations where, in MR, having attunuated lights & no shadows causes 'black' to be added (for a lack of a better term-more like multiplied) to objects after the attenuation reaches 0 light intensity. But only when rendering with MR.

 

WDA

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I have converted everything to an editable mesh. I have split the scene into two and XRef'd them (just to see if it made a difference with the building in the scene or not). I have welded all vertices. I have redone the lighting - this time I have a skylight with HDRI and one raytrace drectional light. I have patched up my differences with God. I helped old ladies cross the road and I have forgiven others who have crossed me in the past. I have however found that if I DON'T specify a Maximum Sampling Radius the black blobs don't come back. :) However with my new GI settings Max does a 'fast exit' with FG enabled. Outta the frying pan into the fire or something to that effect.

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Ok - today I uninstalled MAX and all plugins + GIMP and any other software that I thought may not fall under a common scenario for todays GC artist.

 

I then reinstalled MAX - not reinstalling SP1 and RPC plugin. I used default settings and installed the latest Nvidia GFX driver.

 

I got from archives an earliy verion of the file and tested on that an the blobs where still there. I altered my GI settings turning off max sampling radius and MAX again would fast exit with FG enabled. I turned on FG but with the samples turned down to just 8. I then multiplied by a factor of 8 until it crashed - I got to 48.

 

I have sent this scene off to render. The next one will be a day to night animation. The only thing I aven't done is convert everything to mental ray materials - I will do and post if it works or not.

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