Have been facing this problem for a quite while. I’ve worked in other 3d software (Maya & 3ds Max) but never faced this problem. As far as I know I’ve never faced this problem before version 2.8. May b I m wrong. Cause I’ve started blender seriously for our project after 2.8.
Whenever I extrude a face inwards at the side of an edge, after extrusion there’s always been a face remained.Don’t know why. If it is a simple object I can just delete the face or merge the vertices. But I m currently working with a complex object & it’s really a pain in the $$ to delete those extra face. I searched for settings & other extrude option but never found any solution. As far as I’ve seen, from 2.9 there is a different extrude option which eliminates my problem. But I m currently working in a team who are using version 2.83.2 LTS & they decided to stick with the LTS version for the longevity of the project & for the long time support for LTS version. So can anyone help me with this problem??? Would really be a great help… Thank you.
Good day, I think you mean the Extrude Manifold option, and so may I inquire, why not upgrade to Blender 2.9? It also has snap in vertex slide mode. If you upgrade you can still work the same in your files. Now that being said, if you really don’t want to upgrade, what I do for your case is (and this may not work for you still)
Extrude the edges, NOT the face, only the edges that you want to move into the object, and extrude them in place, without moving them after extrusion. In Blender shortcuts it would be: select edges, press E, then right click to leave them in place.
Turn on X-Ray vision and select the newly extruded faces and the face you want to move inside de object. The new faces will look like edges because they originated from extruding edges, you can be sure that you are selecting faces if you turn on the Center option in Overlays -> Mesh Edit Mode -> Center, to display dots in the center of faces
Split the selection from the mesh, with Blender shortcuts press Y, or with menus go to Mesh -> Split -> Selection
Select only the face you want to move and move it inwards, it will move inside the object without the intersecting faces
Select all vertices and merge by distance, or if your mesh is too big and selecting all vertices slows down your computer then just select the vertices that are split from the mesh, where you did the split operation in step 3.
After testing this method, this doesn’t give the exact same result as the Extrude Manifold from Blender 2.9, if what you want is the exact same result as the Extrude Manifold, then you can do this:
Create an auxiliary mesh and edit it so that it has the shape of the hole you want to make.
Position the auxiliary mesh in the place where the hole will go.
Add a boolean modifier to the main mesh and set it with the Difference operation, and in the Object field select the auxiliary mesh. Apply the operation
Testing this method I get the exact same result as the Extrude Manifold, and if you think about it, the Difference operation is like a Extrude Manifold, when done in the border of the mesh, and in the same conditions.
