Displacement map for 3D printing

I’ve been using Blender for a few years but I still consider myself a novice.

I’m trying to 3D print a small collection of toy tree trunks that will end up being about four inches in diameter and about ten inches tall. I can handle the 3D printing part once it’s an STL. I can also slap a few cylinders together to get the general shape of a tree trunk with a few roots sticking out. Where I’m lost is how to apply a texture that will print.

I want to walk down to the park, take a few photos of tree bark, and wrap that texture around my cylinder (without modifying the top or bottom). But I don’t want it to just look that way on screen, I want the treebark texture to become part of the cylinder surface (not the caps though) so it will print. I think I need a displacement map, but I don’t know how to manipulate it to get the effect I want. In fact, I barely understand how the displace modifier works. I tried adding a color photo as a texture then tried using that with a displace modifier. I got something that looked like a porcupine. Can anyone point me towards a tutorial or give me an outline on how to accomplish this?

I tried adding a color photo as a texture

Displacement modifier works with black and white image. Displacement is based on difference in gray value. Convert your color image in to gray scale image and see how it looks.

Also to get fine texture, you will need fine mesh to begin with. Take a look at this tutorial:

That’s a great tutorial. I’ll convert my image to black and white and try again this afternoon. Is there a way to have the modifier not affect the caps of my cylinder, or is there another trick if I want to retain a basic tree trunk shape?