bump artefacts

[Stefj]

hi,

i use some JPG / PNG i created to simulate bump mapping.
the problem is some artefacts appears despite the high quality JPG i create ( RVB / 300 Dpi / 1/4 scale / 16 bits gradients... )
my photoshop / JPG file is clean.... but not the render result...
some ideas ?

[richardfunnell]

Hi Stefj,

It looks like your bump height is set to a relatively large value (-4) which can cause artifacts especially if the beginning texture is relatively low contrast. I usually try to stay within the -1 to +1 range.
Planar projection (like you used) or UV coordinates help keep the results cleaner, but you may have to change either your bump height or starting image to decrease the contrast.
My suggestion is to create a Normal Map based off your bump texture to get better results. The easiest method is in Photoshop CC (Filter > 3D > Generate Normal Map...), or use an application like CrazyBump or PixPlant.

[Stefj]

so... maybe if i use a more contrasted bump map picture with a lower value ( +1 to -1 as u suggested ) , it will remove the problem ?
i created and use very HD texture ( 300Dpi / 1/4 scale of real dimensions )... maybe i can use lower texture ?
i will try  CrazyBump n PixPlant, thanks !

[Chad Holton]

If all else fails, try using the picture for displacement mapping in your modeling software (if possible) and then send it over to KeyShot. Then use bump mapping for smaller details in KeyShot.