I believe it was once possible to set negative displacement (inward) in blender, I have always considered 0,5 to be the value associated with NO displacement, anything below that negative (inward) and anything above that positive (outward); but recently feeding a black image to Cycles directly on the displacement slot with experimental feature True Displacement (2.78c on Mac Os) returns no change and any value is considered positive (outward) Am I doing something wrong? how can I achieve inward negative displacement?

Thanks. -G

The Problem

  • 1
    $\begingroup$ I haven't tried it, but a couple things that might work. 1. Put a math node in between your image texture and material output (then set it to negative) 2. or bring image into PS/Gimp and use a 50% grey for no change, black for the parts you want to go in, and white for the part you want to be extruded. Just some thoughts. If I have time tonight I will check if this works. $\endgroup$
    – icYou520
    Commented Jul 17, 2017 at 22:13
  • $\begingroup$ when i feed a 50% gray image a partial displacement appears $\endgroup$
    – Zaldor
    Commented Jul 17, 2017 at 22:19
  • $\begingroup$ hmmmm. I will try to do this later tonight if I can. $\endgroup$
    – icYou520
    Commented Jul 17, 2017 at 22:21
  • $\begingroup$ Try inverting the color of the displacement map with a Color > Invert node $\endgroup$ Commented Jul 18, 2017 at 0:11
  • $\begingroup$ To get gray as midpoint you need to add a math node and subtract 0.5. At that point mid-gray will be no displacement and anything darker will be negative displacement. $\endgroup$
    – user1853
    Commented Jul 18, 2017 at 0:20