Ribbed surface

men )

trying to make nice ribbed metal surface in cycles
have map

but render gives me unpleasant noise

using displacement also gives not nice result

missed something?

p.s. sizes are very small - centimeters… maybe this is problem

Yep. Missed. Missed the fact that jpg is the worst image format due to compress/uncompress losses of information/distortions introduced.
For the real displacement (cons - heavy on vertices objects needed) best option is full 32-bit scale images - OpenEXR as a first candidate.

Missed that Blender can generate such stripes in full glory if you use Wave texture.

yep ) 10x… i thought it jpg artefacts but…

wave tex is a nice idea )
but how to map it correctly on cylinder?
for UV map & unwrapping its simple

this is real photo of object

Royal Enfield petrol tank cap )

10x man ) i thought it was jpeg artefacts but )
waves are nice idea )
but how to map it properly on cylinder?

UV image is not a problem but this texture

this is real object’s photo

Royal Enfield’s petrol tank cap )

10x man )
got it