adamantine Posted February 5, 2008 Share Posted February 5, 2008 Hello, I'm newbie to mental ray. I have a problem with speckles in my rendering, attached. Can any mental ray masters explain why this is happening and how to clean the white dots? Thanks for your attention! Some of the settings are: Final Gather preset low, noise filtering high, trace depth max. all set to 2, no GI, no caustics, everything else default. The materials are all A&D, the glass is the preset "glass". Others are mattes, and brushed metals. Logarithmic Exp Control - 7100physical scale, exterior daylight checked (to have a glimpse of what is outside other than bright white) Let me know if you need more details Again, thank you! Link to comment Share on other sites More sharing options...
Justin Hunt Posted February 5, 2008 Share Posted February 5, 2008 Has draft mode been selected? Also just be aware that the brushed metal preset has bump mapping applied which could be at the wrong scale Dont use the high noise filtering, it increases the rendertime greatly. Up the max trace depth back to the default of 5 and the refelction to 2 JHV Link to comment Share on other sites More sharing options...
robkar97 Posted February 5, 2008 Share Posted February 5, 2008 I find the "mr photographic exposure control" is easier to use. If you have 3ds max 2008 I would recommend you have a look at it. It's located in the same dropdown as the logarithmic control. Robert Link to comment Share on other sites More sharing options...
adamantine Posted February 6, 2008 Author Share Posted February 6, 2008 Thanks for the replies guys, No, the draft mode is not selected. The only way to reduce the dots is to turn off shadows (raytrace) of the ceiling lights (area lights). But unfortunately its still there, on the surface of the brushed metal materials. I'm pretty sure that the material is the problem, but I can't seem to fix it. The brushed metal material is an A&D material. It does not have a bump map, but a noise reflection color. The 3ds max unit setting is inch/feet with correct scale. I got various results with noise size settings, but the dots are still there... this is really frustrating... Oh, and i'm using 3ds max 2008. I will try mr photographic exp control. Any more ideas? Maybe good settings for an aluminum material? Thank you Link to comment Share on other sites More sharing options...
Justin Hunt Posted February 6, 2008 Share Posted February 6, 2008 what are your image sampling settings? Here is a quick set up. Take note of the metal settings, I have made a few tweeks to the default values. Things I have changes 1) Turned on fast interpolate, check the settings for other tweeks 2) Changed the BDRF to IOR and set the IOR to 50 3) Turned on Rounded corners Also check out the GI and FG settings, the sun photon radius and the photographic exposure control. Note I am using gama of 2.2 JHV Link to comment Share on other sites More sharing options...
robkar97 Posted February 7, 2008 Share Posted February 7, 2008 Just curious... IOR = 50 sounds extremely high? Does the value mean a different thing when using fresnel reflections compared to how it is used in refractions (where you typically use 1.0-2.0, 1.5 for glass)? Robert Link to comment Share on other sites More sharing options...
robkar97 Posted February 7, 2008 Share Posted February 7, 2008 Are the area lights casting shadows extremely large? If they are, I guess weird things could start to happen... Are you using [x] Enable area sampling, and if so, how many samples are you using? I mostly use 32, which renders rather quickly and gives almost perfect results, maybe a little noise. Since you got really large panoramic windows, try using a "mr sky portal" light to help final gather. Should render faster and look better! Robert Link to comment Share on other sites More sharing options...
Justin Hunt Posted February 7, 2008 Share Posted February 7, 2008 Check out Master Zaps blog for a better explanation http://mentalraytips.blogspot.com/, look for the "Making Better Metal with mia_material" post Ok just checked it's 40 which is possibly a little high but I liked the result JHV Link to comment Share on other sites More sharing options...
mdviz Posted February 7, 2008 Share Posted February 7, 2008 Taking Justin's test scene a little further, I added a glass window, skylights and applied a A&D mat with the brushed metal pre-set to the scene and rendered with box 1/16 1/4 to get similar though fewer artefacts to your scene. I then simply upped the sampling quality to lanczos 16/1 and rendered. The render looks looks fine to me. Obviously render times are increased quite a lot but no artefacts. Maybe this is a simple sampling quality issue? Link to comment Share on other sites More sharing options...
chad5118 Posted July 9, 2009 Share Posted July 9, 2009 (edited) are you running a Dual or Quad Core ? these kind of artifacts has been known to be a issue with Multi-cores on some systems.and is link directly with Mray. granted im running into a similar issue in mine useing maya 2009 but its more subtle. see below Edited July 9, 2009 by chad5118 to give example and show my issue Link to comment Share on other sites More sharing options...
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