Author Topic: Artifacts in direct light  (Read 2356 times)

2019-05-02, 19:42:31

actrask

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I'm getting weird shading artifacts, has anyone seen this before? The ball on the left has the same material applied as the artifact-y mesh on the right. This is the direct pass of a single corona light with a simple corona material applied. This was a purchased model, so I'd like to be able to use this mesh and not have to re-create it.

2019-05-02, 19:49:28
Reply #1

actrask

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I opened up the mesh in a fresh scene and still have them, fyi

2019-05-02, 19:53:19
Reply #2

actrask

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rendered the same mesh in Arnold and don't get the artifacts

2019-05-02, 20:00:19
Reply #3

Frood

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Looks like Max+explicit normals. Quickhack you can try:

- add a box to the scene
- add an Edit Mesh modifier to the box
- attach your geometry to the box
- delete the box part from the mesh
- smooth object as you like and have a look how it renders now


Good Luck



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2019-05-02, 20:27:52
Reply #4

actrask

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Thanks for the quick reply, but no it didn't :(

Would exporting as some other format and re-importing it fix it?


2019-05-02, 20:42:22
Reply #6

Frood

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Don't know where your file is from. The attach method worked for me almost every time. Best would be if you could attach a part from that geometry here? You could also try the other way: Edit Mesh -> subobject element -> detach all as clone.


Good Luck



Never underestimate the power of a well placed level one spell.

2019-05-02, 21:26:29
Reply #7

romullus

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Doesn't look like explicit normals to me, but it's very easy to check - just add edit normals modifiers and tell us what colour have normal handles. If it's blue, then everything ok with your normals.
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2019-05-03, 08:26:59
Reply #8

Njen

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The last resort for me if the attach method doesn't work, is to simply select all of the verts, and weld them (with a low tolerance, so that you don't get unwanted welds). I can't explain why seemingly welded verts have their normals fixed when all verts are welded, but it does work in those fringe cases for me.

2019-05-04, 01:59:54
Reply #9

actrask

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I did try the weld verts at 0.001, because that usually fixes any weird mesh issues for me. Didn't work here though. I moved onto another prop, but it'd be nice to know how to fix that in the future if it ever comes up again.

The asset came from Design Connected, I suppose I could try to find the artist and ask what the model was originally created in for clues. For the record Design Connected usually has great models.

I'll attach the mesh here when I'm in front of a computer. Thanks for all your help!

2019-05-04, 13:46:50
Reply #10

sprayer

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guys you did't notice it's not a wire pattern. better to see scene

2019-05-04, 14:36:53
Reply #11

pokoy

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Would you be able to share only a part of the object that displays the problem? I'd like to inspect it.

What was the original format of the mesh?

Max sometimes messes up normals, exporting as obj and reimporting, with normals unchecked during export, always did the trick for me when all of the tools available in Max failed to clean up normals.

2019-05-16, 16:12:55
Reply #12

maru

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Two ideas:
1) Convert to editable poly > select all faces > retriangulate button (from the editable poly ui)
2) Enable devel/debug rollout (https://coronarenderer.freshdesk.com/support/solutions/articles/12000021288), then change terminator shadow shift to 1.
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