Rendermesh shown in final render when using Dirt Texture as Bump Map

[monksalve]

Posting this in the Bug section now that I have priviledges

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I'm trying to use the Dirt Texture to mimic the irregularities in a gloss plastic part (sink marks, slight ridges at edges). It works well except it renders some odd lines on the surface which I've figured out are the rendermesh. See attached sample. Any idea what might be causing this? The geometry is imported as STEP. Native geometry doesn't seem to have this issue but I have not quite proved that completely (would need to remodel the whole thing, want to avoid that).

Here is a non comprehensive list of what I've tried:

- Turned every knob, button and slider on the dirt texture options
- Increased resolution of rendermesh. Edges still showing.
- Tried variations of global illumination vs direct illumination
- Used different Anti-Aliasing Filters
- Used Progressive vs Adaptive Rendering
- Scaled object smaller and larger
- Imported object as a native Solidworks File instead of a STEP file
- Exploded and re-knitted object

All this to no noticeable improvement. In fact, I think it's gotten worse.

Any help welcome. Thanks!

[Peter.Chaushev]

Hello, and thank you for reporting this!
As I just replied in your other thread, could you please pack the scene (or at least the glitchy part of it) and send it at support@chaosgroup.com for investigation?
If it is alright, please send the source file as well.

Kind regards,
Peter

[monksalve]

Hello, and thank you for reporting this!
As I just replied in your other thread, could you please pack the scene (or at least the glitchy part of it) and send it at support@chaosgroup.com for investigation?
If it is alright, please send the source file as well.

Kind regards,
Peter

Done! Thanks Peter

[Peter.Chaushev]

Hello again,
Thank you for sending over a sample project!
Slotting a Dirt texture in Bump slot/mtl will actually always produce this effect. These are both raytraced texture (calculated on render time). Regard the resulting "seams" as a known limitation.
My advise is to use a different texture for the Bump Mode/Map slot and have the Dirt texture slotted in Bump Amount instead. This will allow the Dirt to control the bump effect distribution. Resulting effect should be pretty much the same (minus the "seams").

Kind regards,
Peter