derijones Posted February 25, 2005 Share Posted February 25, 2005 Hi folks I use Maya 6 with mental ray 3.3. On the current project I'm doing I have black spots appearing on the image (see attached) - as if Mental Ray can't create any data for those areas. There is some discussion on the CG networks newsgroup, but the suggestions there don't seem to work. The scene is lit with a HDRI image based lighting node and a spotlight based MR area light for the sun - pretty simple. There is only FG, no Global illumination and as far as I can tell, FG isn't causing the problems - I've tried between 100 rays and 2000 rays and still have the problems - the image looks fine in the FG preview. Using just Raytracing gives the same problem. I don't think it's geometry, as the initial setup and test renders worked fine - I've tried breaking the scene down in to just the house and same problem. Shaders are pretty simple - blinns mapped to jpeg files, so I'm guessing it's in the MR setting somewhere, but can't figure out where, as they are the same as I use on other jobs with no problems. Anyone got any similar experience or ideas on solutions - Photoshoping them out is job I could really do without, as I'm eating up days with this project anyway...... Many thanks Deri Link to comment Share on other sites More sharing options...
glenoe12 Posted February 28, 2005 Share Posted February 28, 2005 oops! Link to comment Share on other sites More sharing options...
Christopher Nichols Posted March 1, 2005 Share Posted March 1, 2005 dude... he's not using Vray Link to comment Share on other sites More sharing options...
voltaire_ira Posted March 1, 2005 Share Posted March 1, 2005 make sure that your fg map calculation has the "rebuild" option turned on...it is possible that your fg is using the saved fg map and changes have been made in your scene. i'm not sure if maya's mr has a rebuild checkbox/option. Link to comment Share on other sites More sharing options...
derijones Posted March 1, 2005 Author Share Posted March 1, 2005 Thanks for the replies - much appreciated.... Indeed I'm not using Vray, but thanks anyway!http://www.cgarchitect.com/vb/newreply.php?do=newreply&noquote=1&p=66096# Wink The FG rebuild is on and there doesn't seem to be any holes in the FG preview (some of the holes are big enough to cover several dozen FG points). I'll try re creating the links to maya iff format files rather than Jpeg, but as some of the holes are appearing on areas with basic shaders (eg glass), I can't see this being the problem. I've photoshopped the holes out and the customer is a happy bunny, so I guess for this job it's a case of putting it down to experience and hoping that it doesn't raise it's head again. Thanks Deri Link to comment Share on other sites More sharing options...
3DArchitecture Posted December 22, 2005 Share Posted December 22, 2005 I have come across the exact same problem with Mental Ray but in 3D Studio Max 7.01. I have not been able to track down the problem either. Changing settings only moves the black holes/spots around. The problem will get worse as you increase resolution. It may be a bug with Mental Ray. I have stripped scenes to one material with no textures, one light and can still recreate the problem. I ended up photoshoping out the black holes too but this is a problem when creating an animation! Link to comment Share on other sites More sharing options...
3DArchitecture Posted December 26, 2005 Share Posted December 26, 2005 Problem: Black spots appear in Mental Ray renderings. Reason: Final Gather does not work with Multi/sub materials with Raytrace reflections that are "FACETED". Solution: Turn "FACETED" OFF. See 3DS MAX files attached. Kenneth Loyd Link to comment Share on other sites More sharing options...
whoodt Posted December 29, 2005 Share Posted December 29, 2005 Hi, I've got the same problem I cant shake. There arent any faceted material nor multilayered material in my scene and I got these massive ugly black spots happening as well. I've been doing incremental production renders and one day the spots just appeared. I wonder if it's a memory issue as I kept adding stuff in the scene. Help! Hubert Link to comment Share on other sites More sharing options...
3DArchitecture Posted December 31, 2005 Share Posted December 31, 2005 Try restarting MAX, go to files > reset scene. Save the empty scene with a new name. Then merge one object at a time until you can recreate the black spots. Then isolate the object causing the problem and check it's material properties. Zip it up and post it if you need more help. What version of MAX are you using? Link to comment Share on other sites More sharing options...
whoodt Posted December 31, 2005 Share Posted December 31, 2005 I'm on max 7 without SP yet... All that stuff's at work so I can post. But I like you suggestion. If it doesnt work, I might just jump off that same bloody building I'm rendering. Cheers. Link to comment Share on other sites More sharing options...
USED Posted January 13, 2006 Share Posted January 13, 2006 I seem to think that this is due to having displacement maping.. I had a massive Land surface, and that is it, one mesh with a 1gig texture and a displacement map. With the displacement on i got the black spots, with it off I did not. Link to comment Share on other sites More sharing options...
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