Extrude is not creating thickness


This problem has surfaced several times on my different Blender projects but I never quite figured it out.

I have attached a sample file because it’s a bit hard to explain otherwise. In the sample file I have colored a wall that I want to make thick with a red material. But when I extrude this face on the x-axis it only pushes it around and doesn’t create thickness like extrude usually does. Can someone explain why that is?extrude question.blend (445 KB)

Its fine from my side with your file. May be u might have turned on snapping/Pivot point might be in individuals origins.

I suspect I wasn’t clear enough with my question.

If you press e --> x --> 1

and then go look at the wall from inside, does it look like a thick wall or an empty room? I need to make it a thick wall but instead I get a hollow room.

Then don’t scale it in x-axis, scale it globally by pressing e–>esc–>s i guess you are expecting like this



I think we are still talking about a different result so I made a new blend file which has a blue version of the mesh representing what I want to get by extruding the red wall.
extrude question modified.blend (447 KB)

i guess you achieve it by Solidify modifier easily…


Solidify is a nice modifier, but what bothers me here is that I don’t really understand why this is happening. If I have a simple plane and I extrude it, it gets “thick” (meaning it has faces on each side). But when I extrude in the example file I dont get faces on each side but the other side is like an empty room (instead of a thick wall).

What is different in my scenario compared to extruding a simple plane?

One of the edges around your selection belongs to more than one face. When you extrude, Blender considers face(s) left behind as internal and those get removed.

You could use solidify tool from the faces menu (ctrl+f) instead. F6 to show the properties.

The normals are facing inward. This happens when you extrude things toward the surface normal, while when extruding away from the surface normal the polygons will point in the correct direction. Just select everything and recalculate normals or remove doubles, select the offending polygons and flip them.

Simplest workaround is to create a floor plan where the knife tool creates the inner walls. Once this is done, shift-d the design, separate it from the original mesh, perform upward extrusions on the new mesh. When done join meshes,remove doubles