I have a mesh which has quad vertices but when I try to click to select the edges of the mesh, it stops where the red circles are. But as you can see around the edge of the mesh, the rest is selected. Shouldn't it be able to select the edges since its all quad faces, there are no Ngons or triangles.
1$\begingroup$ Maybe you have double vertices ? Try selecting everything with "A" > Right Click > Merge Vertices > By distance $\endgroup$– GorgiousFeb 14, 2020 at 8:12
$\begingroup$ I tried that and it says removed 0 vertices, here another version of a mesh which does the same thing. ibb.co/CvxczYF $\endgroup$– blender breathFeb 14, 2020 at 9:29
$\begingroup$ @bruno Thank you for improving the question, however, titles should actually state the question, where possible. $\endgroup$– Ray MairlotFeb 16, 2020 at 17:12
$\begingroup$ Got it, thanks @RayMairlot $\endgroup$– BrunoFeb 16, 2020 at 21:16
Your topology has corners, which break the edge loop.
You can solve it by a small Inset, to keep your edge loop connected.
If you want to continue selection through corners, just click again :).
1$\begingroup$ Hi Jachym, thanks for the insight. I was sceptical why it wouldn't loop around the edge, until you implied there's a break in the corners, but again it's a quad... But I'm not a stage to understand why Blender does this, since almost every tutorial I'm following always recommend quads for better functionality. Kind regards. $\endgroup$ Feb 14, 2020 at 9:38
$\begingroup$ This is intended functionality. To select through corners, just click again :). I edited the answer for you. $\endgroup$ Feb 14, 2020 at 9:44
Jachym Michal has the solution, but I thought I would just clarify the underlying cause a little more given your comment.
Topology is only concerned by how vertices are connected to each other. The two meshes below have exactly the same topology, and serve as a good visual illustration of why your edge loop selection was curtailed. As far as the topology is concerned, the cylinder is the cube. If you select the magenta edge loop, Blender doesn't know which way to continue at the pole, down cyan or along yellow.
Edge loops won't continue through poles, which are vertices that don't have four edges coming out of them. The most common of these are N poles (as here, with 3 edges), or E poles (with 5 edges), but you can have poles with any number of edges coming out of them theoretically.
I'll also throw in another potential solution, which could be more or less useful depending on your specific mesh: Use Bevel with Segments: 2 and Profile: 1.0 to add a loop of faces to either side of an edge you wish to make into a face loop.
1$\begingroup$ nice complement of info and tip @rekov $\endgroup$– BrunoFeb 16, 2020 at 21:21