So, I am still learning and have a big PBR kitchen scene planned with lots of elements. This time I am focusing on precision and making sure my workflow doesn't introduce any anomalies so as I get better and faster I am not building on a shaky foundation.

So, I am making a window, and I am getting hung up on it early on as I carefully go over steps I missed (edge-looping the trim for example) and have been using the select>non-manifold option to double check things, and it revealed some unmerged verts as well as some useless interior edges. I've sorted everything out, but three verts still flag as non-manifold and I can't for the life of me determine why.

enter image description here

As you can see, I have the verts selected, and all makes sense. Three verts connected at the vert shown with 2 edges and 0 faces. I checked the other two, did a walk through the inside using the walk function, selected all verts in question using box-select and xray to find duplicates, checked normals, everything. I am frustrated cuz I work full time and I am ready to move on from this part, but I don't want to build bad habits.

Is this just a known thing that can happen? I built this object from a single vert to get Milimeter precision, but that shouldn't be an issue. I have a couple of CAD addons (CAD Transforms et al), maybe one of them is causing this? Is this just a known phenomena?

Thank you all in advanced for your help.

Edit: the .blend file in question:


1 Answer 1


If you would unhide all geometry with Alt+H (and maybe enable the Face Orientation overlay), you would see that these non manifold vertices are connect to an edge loop of vertices which has a flipped face lying unconnected over the other face and the rest is just edges without faces. I guess this was supposed to become or is a remain of a window pane? What makes these 3 vertices you showed now non manifold is the fact that they are connected to the other hidden non manifold edges.

By the way, since you are using the Statistics overlay, an indicator for hidden geometry is the fact that when you select all with A, it shows only 696 vertices of 700 selected. There are 4 not visible and therefore not selectable.

missing vertices

hidden geometry

flipped unconnected face

  • 1
    $\begingroup$ Thank you so much! I know now to check the total verts to look for hidden ones. I had no idea that had gotten hidden. Thank you! To answer your question, the windows are already made, this is the wood spacing. Quite possibly the least important object here, but I am glad I asked cuz I learned how to troubleshoot better. Thank you again! $\endgroup$ Dec 9, 2023 at 15:45

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