Mental Ray - black blobs help

derijones · May 23rd, 2005

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!)

derijones · May 23rd, 2005

Another view -

J.R. · May 23rd, 2005

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...

derijones · May 23rd, 2005

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

mohamedberry · June 20th, 2005

Hey... i had the exact problem and it turned out to be caused by wrong saved GI values, so all you'll have to do is to restart & regenerate your GI

enigma · June 23rd, 2005

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.

nisus · June 30th, 2005

My guess is that you use architectural materials??? Change to standard

nisus

wda · June 30th, 2005

WOW!!! That's extreme LOL

Up the sampling, and make the sampling area smaller. I'd check the Hdri for very dark areas and the area light settings-as those maybe 'sampled' to low also. I've never seen mental ray, without GI photons produce anything so dark and well defined.

WDA

bcampbell · July 4th, 2005

I am suffering the same right now. I am wondering if this is the 'flag as black' option for illegal video color?

nisus · July 4th, 2005

NO! It's a material error! --> Standard!

nisus

May 23rd, 2005	#3 (permalink)
J.R. Member Join Date: Nov 2002 Location: Vienna Age: 33 Posts: 41 Name: Jan-Ruben Fischer	Re: Mental Ray - black blobs help 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...

May 23rd, 2005	#4 (permalink)
derijones Senior Member Join Date: Oct 2004 Location: Wales Posts: 119 Name: Deri Jones	Re: Mental Ray - black blobs help 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

June 20th, 2005	#5 (permalink)
mohamedberry Senior Member Join Date: Apr 2004 Location: Kuwait Age: 28 Posts: 145 Name: Mohamed Berry	Re: Mental Ray - black blobs help Hey... i had the exact problem and it turned out to be caused by wrong saved GI values, so all you'll have to do is to restart & regenerate your GI __________________ Mohamed L Berry Zone Designers

June 23rd, 2005	#6 (permalink)
enigma Senior Member Join Date: Apr 2005 Location: Imus, Cavite, PH Age: 29 Posts: 342 Name: Bryan Jumarang	Re: Mental Ray - black blobs help 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. __________________ WIP...

June 30th, 2005	#7 (permalink)
nisus Super Moderator Join Date: Mar 2002 Location: Gent Flanders Belgium Europe Age: 32 Posts: 3,276 Name: Evert Vandenberghe	Re: Mental Ray - black blobs help My guess is that you use architectural materials??? Change to standard nisus

June 30th, 2005	#8 (permalink)
wda Veteran Member Join Date: Nov 2002 Location: Dallas TX USA Age: 44 Posts: 1,021 Name: William Alexander	Re: Mental Ray - black blobs help WOW!!! That's extreme LOL Up the sampling, and make the sampling area smaller. I'd check the Hdri for very dark areas and the area light settings-as those maybe 'sampled' to low also. I've never seen mental ray, without GI photons produce anything so dark and well defined. WDA __________________ From the calm seas.... Into the CG Fire...... Into the Heart of Texas

July 4th, 2005	#9 (permalink)
bcampbell Junior Member Join Date: Jun 2005 Location: Hamilton Age: 34 Posts: 23 Name: Brian campbell	Re: Mental Ray - black blobs help I am suffering the same right now. I am wondering if this is the 'flag as black' option for illegal video color?

July 4th, 2005	#10 (permalink)
nisus Super Moderator Join Date: Mar 2002 Location: Gent Flanders Belgium Europe Age: 32 Posts: 3,276 Name: Evert Vandenberghe	Re: Mental Ray - black blobs help NO! It's a material error! --> Standard! nisus

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