# Remove geometry on "inside"

I have a mesh that has a internal geometry but not like vertices inside of a closed geometry but rather the faces that are not visible from the outside let me explain with an image:

as you can see the red area indicates the faces on the "inside" how would I go about removing these?

I want to remove the internals to reduce the vertex count! since I won't ever see them anyway.

If my question is unclear or needs extra info let me know so I can clarify!

• WIll depend on mesh. Would try select all verts on "red" inner loop. Delete them. Select a vert on inner surface, grow selection, delete. If there are other edges faces connecting inner with outer will fail. Dec 29, 2018 at 14:48
• sounds like a good option! what exactly do you mean with grow the selection? do i need to do that manual or is there a function that selects adjecent vertices with in a specified distance? Dec 29, 2018 at 15:20
• ctrl + grows a selection. Dec 29, 2018 at 15:59
• [ctrl]+[Numpad +] grows selection, [ctrl]+[+] zooms in
– rob
Mar 19, 2019 at 13:09

if youre using 2.92+ try using a boolean modifier over your mesh and in "operand type" click "collection" without adding a collection

this has the nice hidden feature of eliminating all inside faces

gif example below

also if it doesnt solve your problem try Ben's aproach in the other answer as this boolean operation will close the mesh and merge 3D sahpes but will leave 2D planes inside still

• sure thing, added example Apr 28, 2021 at 4:36
• Ah I see now, apparently it only works if the inside and outside intersect. Apr 28, 2021 at 16:49
• Interesting, it did remove all inside faces, it also nearly quadrupled the tris count of my model 0_0 Nov 21, 2021 at 22:28

Try the select Interior Faces Command and see how close it gets you.

• That probably won't do it, since the faces in OP's image aren't really on the inside. You need a closed mesh for "Select Interior Faces". Dec 17, 2019 at 21:22

Select everything you can see from the outside (with limit selection to visible on) then press H to hide them. If you've selected everything correctly, there should only be internal vertices left which you can then delete. Press alt-H to bring them back when you are done.

Depending on how complicated the structure, getting all the right vertices hidden could be a pain, but this should work.

• This is a pretty rough way to do this, and it works! Though to avoid borked faces I found that only using delete faces only to be the only option. It leaves lots of edges & verts behind, but doesn't seem to risk problems you have to go back and fix. Nov 21, 2021 at 22:33