Weird shadow lines on plain surfaces of mesh

[Soundwave2142]

Hi, can anyone point out why am I getting this weird shadow lines? It is mostly visible during sunsets when sun shines on plain surfaces
DAF 105 by SCS doesn't seems to suffer this from this problem much, even thought it has similar plain surfaces.

Any ideas how to at-least reduce this issue?





Beginner modeler, don't judge!

[Etrusan]

Might be self-shading, try to give the shadow material negative bias (-0.5 works somewhat ok).

[Soundwave2142]

**Rule 2.12**

I don't have a shadow option on in any of my materials. However I tried ticking it on right now, just for testing, doesn't seems to effect anything, also I can't enter a negative value in shadow bias in blender.

Here's how (that blue panel) material looks like (and most of them too):

[Dotec]

for negative value:

open io_scs_tools/properties/material.py and go to line 633
change this line

min=0.0,

to

#min=0.0,

save and try again

[Soundwave2142]

As I said, none of my materials had shadow flavor on (so "self-shading" shouldn't be a thing, right?). However I did as you said and created new dif.spec material with shadow flavor and bias set to both -0.5 and -0.05. Mesh still suffered same effect, nothing seems to have changed

---

Might be self-shading, try to give the shadow material negative bias (-0.5 works somewhat ok).

Sorry, it seems I misunderstood you. When you said "shadow material" and "self-shading" I thought of materials that has shadow flavor. However setting -0.05 to my mesh that has shadow shader (and acts like shadow caster) fixed the issue.

Thank both of you for the assist.

[ONURKULL]

Try add "weighted normal" modifier to which parts look weird.

[Soundwave2142]

Already mentioned the fix in post above, doubt normal weight has anything to do with the issue I had.