# Why does my loop subdivide not extend around the whole shape?

I am createing a model which has a cylinder shape extruded inwards, and wanted to create some sharper edges around it. I tried using the loop subdivide tool (Ctrl + R) but the "loop" part of it is only reaching half-way along the inner edge

The top portion of this is divided into thirds for this, and I'm not sure why this is happening.

These appear to be 4 sided shapes, so I don't think it's an ngon problem.

• Does this help? blender.stackexchange.com/questions/17870/… – Ray Mairlot Jul 9 '15 at 13:43
• Looks like you probably have double verts or something there – gandalf3 Jul 9 '15 at 19:37
• @gandalf3 can you point out where you see this? I'm pretty new to 3d modeling so I'm not really in touch with what to look for. – Dave Lugg Jul 9 '15 at 21:02

• I will be able to check later today if this is the case. Is Remove Doubles something I should hit periodically if I don't expect them? Or is there a more reliable way to detect they are present? – Dave Lugg Jul 9 '15 at 14:17