Blender Discussions

[jl5086]

So whenever I add any material, whether I make it from scratch, using either RPR Uber ot Principled shader, or even on from the RPR library, I get this horrible pure white interference.  Maybe it's more common than I think, but it doesnt appear with the same model when rendered with Cycles, and if I don't apply any material and render with ProRender it's perfect.  This shows up if there is any light source "activated", whether it's a physical sky, hdri or regular lights.  Even if I turn the light source down to zero, the same "noise" appears just as brightly, but in complete blackness around.  The actual level of the lighting has no effect on it, and if I actually disable the light or environment light it goes away, and is obviously just a blank black screen.  Now if I have the light clamp on,(1.0 as low as it goes), it significantly reduces the brightness of it, but it's still very problematic.  It really appears where it should actually be the darkest, like inside open geometry and from the back sides of open objects.  I'v checked a lot of things like the normals etc.  like under the eve of the house model, in one of the pics I actually have a point light right under it, and it never changes how that noise shows up.  It does develop somewhat worse as the render progresses, but it's there from the first few iterations and as far as like, if I "look" up into the roof between the gap where a gutter would be, the whole inside of the roof gets 100% white pixels, when you would think NO light would get there, and that's even with the only light in the scene at 0% in pitch blackness elsewhere.  now if I strip the 2 materials off and leave none, and render with just default surfaces it is 100% perfect, aside from the normal level of noise which renders away quickly, everything else looks great, and up inside the roof is nice and dark, because there's no light getting in there.  I have tried for days to fix this, and look for answers online, but it is very hard to query for such a specific issue.  please look at the pictures and let me know if I can provide anything else to help.  Maybe I'm just missing some limitation I'm not aware of.         While I'm here also, the reason I'm trying to use blender is because while I prefer Cinema 4D I also have an issue with ProRender in that program,  whenever 2 surfaces are touching or close to each other, but only within certain angles, I get these "black" areas, and I've read that it may be related to phong angles but I can't seem to figure that out either.  Just for the hell of it I also attached the last 2 pics from C4D renders, all I have done between the two screen grabs is raise the sphere straight up until where the 2 surfaces are meeting went from a positive to a negative angle, and you can see the "black" space that forms where they meet, and it is not in any way a shadow because even a spotlight doesn't affect it.  Thanks

FWIW I have figured out that if using rendered view port, ALL of this white distortion in the darkest areas goes AWAY,  and it renders just fine, but of coarse all the modifiers don't show, and I even removed all of the modifiers and left just one basic piece of geometry with the RPR shader material on it, and it is overly horrible without it clamped, a bit less with it clamped, and completely perfect in edit mode.  I don't get it.

I switched from Global Illumination to Direct illumination in the RPR menu. and the problem goes away, I'm guessing in edit mode it might switch to direct.  I've never had to switch OFF GI before, either in Blender or any other program, usually the opposite, I've needed it on. Without GI nothing transparent will look right.  I attached 1 more pic,  this really stinks.

[bsavery]

Hey Jason.  I haven't seen these artifacts before.  Can you attach a scene?  What are your machine specs?

Brian

[jl5086]

I dont Know how to send a .blend file through this forum,  I will if you let me know where.

ASUS ROG B450-f Gaming

Ryzen 5 2400g @4.0ghz

G.Skill 16mb 3200mhz DDR4

XFX RX580 GTR Black Ed. 8gb 1450mhz

Win 10 v1903

Blender 2.8 final

ProRender for Blender version 2.0.112

This is much less pronounced when the clamp is on, but even at it's lowest setting it is clearly a problem, it is as if the light rays just get lost or something strange.  If I have a scene with one light,  and I have just that light enabled but at zero illumination,  all the spots that show the white noise is still just as bright, but everything else is pitch black.  and the longer it renders the brighter it gets, but if I hide the light it's all black, like you would expect.  its almost like those white pixels would be better off just black, instead of bright white.  Thanks, and I hope you can help.

[bsavery]

Zip it and attach to the post.

[jl5086]

I was being stupid, didn't see "attach" before, sorry.

[jl5086]

Hi, Just seeing if you have had any luck with the file I sent?  Heres a few more pics of the issue, and another .blend file these pics are from.  It is is not nearly as pronounced as the house file before, but still quite problematic,  it is a very un-natural "glow" from the cracks and other nooks which should be very dark to be photo realistic.  These same scenes, with different materials show no signs of this light when rendered with cycles.   I was going to convert these RPR materials to cycles, but it appears you have removed the convert option from the release for 2.8.  I had thought I read someplace that in 2.8 RPR materials would be compatible with Cycles already (that the shaders all worked with each other), but the Cycles materials still render black in ProRender and vice versa.

[jl5086]

I really hope this isn't a lost cause for me,  I have used ProRender exclusively and REALLY want to enjoy it in Blender 2.8.  Is there any progress or suggestions available.  Even some kind of work-around,  This image below is with the clamp as low as it will go, and it is still unusable.    I also should mention that the dark blue area on this image is another big issue I am having,  Like the white noise problem this seems to be related to the lighting (GI) It does not directly match any underlying topology, yet if I go in and start adding topo, it will change shape and sometimes I can get it to go away, after making a mess. just like the white light noise these dark areas go away when rendering in EDIT mode (without Global Illum.)  Also just like with the white glow if I render this same scene, with different materials(because these RPR materials arent compatable) in cycles, these dark areas are not there.  I cant stand using Cycles because it is rediculously SLOW, and really difficult to use as a live render.    PLEASE help if you can, thank you.

[bsavery]

I'm not quite getting the same thing.  It appears there is a slight crack, but that's in the model....

[bsavery]

I can however re-create with the house scene... What I will say is I was able to clean this up by doing some mesh cleanup and re-calculating normals to be outside.  It might have messed up normals in the geo.