# Joining Two Complex meshes for 3D printing

Thank you for considering this issue.

I am trying to 3D print a handle that will have a wire running through. As such, I have two meshes to make this handle hollow on the inside: the outer mesh is sculpted (complex) the other mesh is a simple geometric form that is meant to be the inner form of the handle. I have attached images to make this clear.

So far, I have tried to Join them using the Boolean Direct Union operator, but to no avail. The outer form is complex, so it has many vertices. That makes it difficult to join edges or vertices.

My problem is that I want to have this sculpted mesh as the outer form of this object, and the geometric hollow cylinder as the inner form of this object, but I have found no way to combine these two without manifold issues for 3D printing. Ultimately, I need a .stl file for this object.

Any advice would be very much appreciated.

• Could you please upload the blend file? My advice would be to create a new object to be punched out of the outer one. Then just link it with the outer one via boolean - difference modifier. Aug 5, 2021 at 17:32
• I'm sorry I don't quite follow, but it seems that you just want to make a hollow cylinder, so why don't you just create a cylinder primitive mesh, remove the caps, and solidify the mesh with a modifier? Aug 5, 2021 at 17:57
• @James I just updated my post to give you a better idea as to why I couldn't do that. The short answer is that I am not looking for simply a hollow cylinder, but a complex outer form with an inner hollow cylinder. Aug 5, 2021 at 22:52
• Can you upload your blend file to blend-exchange.giantcowfilms.com But I think I understand I'll post an example. You want to make the outer mesh solid and use the inner mesh as a cut out. Aug 6, 2021 at 5:27
• @BouhdySleem have you tried using blender's voxel remesh feature after applying your boolean? Aug 6, 2021 at 14:37

1. Also make inner object solid then do a Boolean - Difference on the outer object using the inner object (as the "hole cutter").
1. Change Solver type to Exact