0
$\begingroup$

I'm a newbie in the Blender world and have a problem where I haven't found a solution even after several hours of trial & error and online research.

I have an STL file with terribly bad geometry. The surface is supposed to be smooth. Except for a special area on the top which is supposed to be roughened. I have grouped this surface into a vertex group. The finished part needs to be 3D printable.

bad geometry, vertex group for displace modifier

As I understand it, I need to repair the unusable geometry with a Remesh Modifier (either Voxel or Sharp) and then use the Displace Modifier to put a texture on the surface of the Vertex Group.

In principle, this also works very well. With the Remesh Modifier I get a really neat geometry and also the Displace Modifier basically leads to the desired result at first. But as soon as I limit the Displace Modifier from the whole part to the area of the vertex group, the texture suddenly disappears.

displace modifier working on on whole part

displace modifier not working on vertex group

I have already experimented with making the Vertex Group into a separate Selection. But then the Remesh Modifier doesn't work as I had hoped.

I'm pretty sure I'm just missing some completely trivial intermediate step. However, I currently don't even know what to search for.

This is my Blender-File:

I would be more than grateful for any relevant hints.

Happy Blending!

$\endgroup$
5
  • 2
    $\begingroup$ Hello please share your file: blend-exchange.com $\endgroup$
    – moonboots
    Aug 16, 2023 at 18:57
  • 2
    $\begingroup$ The remesh destroys all vertex groups, because it completely replaces all of your vertices. So after the remesh, there are no verts assigned to that group, hence no displacement. You could consider a data transfer modifier, after the remesh, targeting a copy of the mesh with no remesh, to copy VGs to your remesh. Or, you could apply the remesh and then paint the VG. Probably, neither of those things are really trivial. $\endgroup$
    – Nathan
    Aug 16, 2023 at 21:41
  • $\begingroup$ Thank you very much for the two feedbacks! @moonboots: I uploaded my Blender file and added the download link to my question. Thanks for pointing that out. $\endgroup$
    – Magestic
    Aug 17, 2023 at 10:58
  • $\begingroup$ @Nathan: I will take a look at the approaches you suggested. $\endgroup$
    – Magestic
    Aug 17, 2023 at 10:58
  • $\begingroup$ @Magestic Thanks but actually I think Nathan has answered, you should apply the modifier is the result suits you, recreate a vertex group and use if for your Displace modifier $\endgroup$
    – moonboots
    Aug 17, 2023 at 12:13

1 Answer 1

0
$\begingroup$

Let's duplicate your object to make a backup, then apply the remesh modifier, from the modifier's dropdown menu, and examine the mesh:

enter image description here

A quick look in weight paint mode shows us that our vertex group didn't survive the remesh modifier:

enter image description here

That makes sense. Vertex groups are values attached to vertices, and none of our original vertices survive the remesh modifier.

We can go ahead and work with this mesh if we want, we'll just have to re-paint the vertex group. We can see that as soon as we start to do so, the displace shows through:

enter image description here

If we don't want to repaint this group by hand, we can use a data transfer modifier to copy it from our old mesh-- in this case, from the backup we made. We'll remove the modifiers from that mesh, move it back to exactly where it was, display it only in wireframe so it doesn't get in the way, and then create a data transfer modifier on our remesh, copying vertex groups on "nearest face interpolated" mode:

enter image description here

If we want to go all the way to a data transfer, we don't even have to apply the remesh modifier. We can't paint by hand in the middle of the modifier stack, but we can data transfer in the middle. So we could remesh, data transfer, and then displace, all live, all non-destructively, if that's what's needed.

$\endgroup$
1
  • $\begingroup$ Many, many thanks! Your last non-destructive approach is exactly what I was looking for. It's even pretty darn easy to implement. Thanks for the introduction to the Data Transfer Modifier. That was completely new territory for me up to this point... $\endgroup$
    – Magestic
    Aug 18, 2023 at 11:56

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .