enter image description hereI have a spherical-like object whose thickness is 1.6 mm. There is a section of the surface that is to be only 0.8 mm thick. So I changed the thickness of the entire object to 0.8 mm, then selected the faces that define that special region, then pressed P to separate it from the rest of the object, then changed the entire object's thickness back to 1.6 mm. So now that special region is 0.8 mm as desired. The problem now is the gap between that region and the rest of the surface caused by the separation. I want to close that gap so that from the outside, the surface looks like a single surface and no one can tell where the 0.8 mm thick region is. What is the most precise way to do this?

I tried moving the edges and vertices of the region so that it intersects with the original surface, but the intersection is not clean (see below). How to do it perfectly so that it looks like the original surface from the outside? enter image description here

When I join the two with Ctrl+J, the two regions share the same edges, so I'm stuck on how to proceed there as well. enter image description here

  • $\begingroup$ Am I mistaken to say there is a subdivision modifier involved here with the model you are working on? Have you tried to remove doubles after you Join the 2 pieces together with Cltr + J? $\endgroup$
    – hawkenfox
    Commented Jan 5, 2017 at 13:33
  • $\begingroup$ @hawkenfox Joining with Ctrl + J makes the two regions have the same thickness again (I tried it), when my goal is to have the different regions with different thicknesses. $\endgroup$
    – prestokeys
    Commented Jan 5, 2017 at 22:37

1 Answer 1


Have you tried smooth vertex?

  1. Select mesh
  2. Edit Mode
  3. Select these vertices/faces
  4. select smooth vertex from the tools panel


Another way to do this is adding the thickness to the opposite direction by flipping the face normals and then adding thickness using the solidify modifier. This will add thickness internally so that the original mesh is not messed up as shown below:

I split the sphere into upper and lower half: enter image description here

I then switched to edit mode and flip normals: enter image description here

Then add the solidify modifier with the desired thickness and apply it: enter image description here

as shown I added thickness -0.8 which was added internally.

I then joined the two meshes:

enter image description here

As shown the lower half has more thickness than the upper half.

I wrote the below script to do these steps between two meshes automatically:

import bpy

ob = bpy.data.objects['Sphere.001']
ob.select = True
bpy.context.scene.objects.active = ob
bpy.context.object.modifiers["Solidify"].thickness = 0.8
bpy.ops.object.modifier_apply(apply_as='DATA', modifier="Solidify")
ob2 = bpy.data.objects['Sphere']
ob2.select = True

A blend file can be downloaded from here:

  • $\begingroup$ No, I didn't. But when I try it now, it does not seem to remove the gap but merely deform the gap. $\endgroup$
    – prestokeys
    Commented Dec 29, 2016 at 3:50
  • $\begingroup$ It will smooth the vertices in this area and should do what you want. Like you keep smoothing these vertices until you get the desired smooth surface. $\endgroup$
    – Tak
    Commented Dec 29, 2016 at 3:52
  • $\begingroup$ Ok. Let's say your method does work. Then it is still a manual sculpting-like solution that will never give the perfect solution I seek (automated and appearing as though nothing was ever done to the surface to begin with). $\endgroup$
    – prestokeys
    Commented Dec 29, 2016 at 3:58
  • $\begingroup$ Well, could you provide your .blend file to have a better look? $\endgroup$
    – Tak
    Commented Dec 29, 2016 at 4:13
  • $\begingroup$ I don't know how to attach .blend files here, but one can just take a UV sphere. Separate a region of the sphere from the rest of the sphere (optionally, change its thickness like I did). And then see if you can join it back to look like nothing ever happened. $\endgroup$
    – prestokeys
    Commented Dec 29, 2016 at 4:34

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