# How do you select the interior faces of a cylinder with an array modifier?

I have a circle with an array modifier. It looks like this:

I'm also using the curve modifier on it. That makes it look like this (slight curve):

It looks kind of clunky because I'm stripping this down as much as possible. Ideally the edge of it would be completely smooth. I want to use the boolean modifier to carve this into another mesh but it's too complicated (I assume) and it's never able to apply the modifier.

To fix that I'm trying to clean it up. So I want to remove all of the internal faces. So I go into edit mode, select by face, and then select Interior Faces. and then ...nothing.

How can I select those interior faces? I know there are faces inside the mesh because I can zoom in and select them individually. If I can't select them is there another way to simplify this model?

I've used decimate and that brings me down to about 248 faces for the mesh you see but it's still not simple enough (boolean modifier still not working).

Another way to get this to work might be to select only the visible faces, select inverse, and then delete. But when I uncheck Limit selection to visible it then highlights all of the "invisible" faces automatically.

• This is a very impractical approach to model something like this, as you would need many boolean operations (which is generally something you want to avoid). I would suggest a much easier approach: modelling the outline with two large concentric circles, deleting everything but a small piece and then making circles at both ends to connect the internal and external circles. After that you can make it a surface and extrude it. – Robert Roth Jul 31 at 0:25
• Oh sure, if you want to do it the easy way you can do that. But what if you want to do it in a more complicated and frustrating way? Then my approach wins every time. ...Anyways, yes, that is a much better approach now that you mention it. I had originally tried it but couldn't get the cylinder lined up with the end of the curve but at the time I didn't know how to put a mesh on a curve which is why I was trying this ludicrous approach. Thanks for getting me back on the right track! – user875234 Jul 31 at 0:35
• Something like this? – Robin Betts Jul 31 at 6:13
• The approach suggested by @Robin Betts is very useful and certainly better than what i suggested for most cases, especially if you want the path of the cylinder to be more complex. – Robert Roth Jul 31 at 10:00
• Okay noyce, I didn't follow the instructions in @RobinBetts link exactly because I started following them and realized I already had what I needed. The steps I used are: 1. Create a cylinder. 2. Use the bisect tool to select half of the cylinder as is explained here. 3. Pull the selected half away, creating a pill shape. 4. Add some edge loops to the pill. 5. Put it on the curve. i.imgur.com/YwW5EoC.png. Thanks again guys! – user875234 Aug 1 at 6:06