I'm trying to fill in this corner to be precisely square (see the image below). There are several ways I've come up with, but they're all terribly time-consuming and inefficient. I'm new to Blender, and I'm 100% sure there is a better way. I'll save us some time and not explain the methods I came up with.

How would you fill it in?

Enter image description here

The red lines I added to the image is in paint as to visually represent what I'm asking.


4 Answers 4


enter image description here

  1. Tab into edit mode

  2. Enable the 'magnet icon' which is the snapping tool.This is used to snap an edge,vertex,face,volume etc.

  3. Next, enable the other icon which has 'two dots in the corner and a line connecting it'.This is the 'Auto merge' option.It is very useful and it automatically merges overlapping faces vertices or edges. But Auto merge doesn't remove internal faces

  4. Now with all these tools enabled select your face and press 'E' to extrude.

  5. Hover over the edge in which you want the extrusion to stop. Now left click to finish.

And viola!! you have filled your mesh!

The tools used here:(just in case you have trouble understanding)

Name: Snapping/Snap tool

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Modes Object, Edit, and Pose Mode

Shortcut Shift+Tab

The ability to snap objects and mesh elements to various types of scene elements during a transformation is available by toggling the magnet icon in the 3D Viewport’s header buttons.

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Vertex Snap to vertices of mesh objects.

Increment Snap to grid points. When in Orthographic view, the snapping increment changes depending on zoom level.

Edge Snap to edges of mesh objects.

Face Snaps to the surfaces of faces in mesh objects; This is useful for retopologizing.

Volume Snaps to regions within the volume of the first object found below the mouse cursor. Unlike the other options, this one controls the depth (i.e. Z coordinates in current view space) of the transformed element. By toggling the button that appears to the right of the snap target menu (see below), target objects will be considered as a whole when determining the volume center.

Edge Center Snaps to the middle of an edge. This snap element only pertains to mesh objects.

Edge Perpendicular Snaps to the nearest vertex in an edge that makes a perpendicular angle. This snap element only pertains to mesh objects.

NOTE Multiple snapping modes can be enabled at once by Shift-LMB the different snapping elements.

Auto Merge

Mode: Edit Mode

Menu: Sidebar ‣ Options ‣ Tool ‣ Auto Merge

When the Auto Merge option is enabled, as soon as a vertex moves closer to another one than the Threshold setting, they are automatically merged. This option affects interactive operations only. If the exact spot where a vertex is moved contains more than one vertex, then the merge will be performed between the moved vertex and one of those.

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  • 4
    $\begingroup$ Nice execution. Though Auto merge doesn't remove internal faces, so you'll need to remove that one manually :) $\endgroup$ Jan 8, 2022 at 10:34
  • 1
    $\begingroup$ oops 😨 thanks for that Jachym,I'll edit my answer :) $\endgroup$
    – Ribbit12
    Jan 8, 2022 at 11:00
  • 2
    $\begingroup$ This is an awesome answer! I would have been wasting time doing it some dumb way for weeks probably. The other answers were good enough for me, but this is even better; thank you! Also, I'm glad you guys here didn't chew me out, because my question wasn't perfect, like they do on programming forms. $\endgroup$
    – Abrobot
    Jan 8, 2022 at 13:47
  • $\begingroup$ Really happy to hear!!! :D $\endgroup$
    – Ribbit12
    Jan 8, 2022 at 14:02
  • $\begingroup$ @Abrobot If you see someone being rude or unkind to you (anywhere on Stack Exchange), press the little flag icon next to their message, and then pick an option (probably Unfriendly or Unkind if they are being rude), and someone will take care of it. Also, Stack Exchange has a Be Nice policy, so being rude is not tolerated anywhere on Stack Exhcange and the moderators will deal with it when comments get flagged. $\endgroup$
    – cocomac
    Jan 8, 2022 at 16:46

Assuming this is a right angle, I would:

  1. Turn Snap -> Vertex on.
  2. Select one of the narrow faces that is inside the corner.
  3. Extrude, and snap to the far edge of the other narrow face (the corner is now filled, but we’re not done).
  4. Select all.
  5. Merge -> By distance.
  6. Select none.
  7. Navigate your view to inside the geometry, and select the two narrow faces (there may be only the unextruded one left, though).
  8. Delete -> only faces.
  9. Select all.
  10. Delete -> Limited dissolve (optional).
  • 1
    $\begingroup$ I thought of something similar, although I didn't know about the snap vertices thing, so that's why it failed when I tried, but is that really the best way? Seems like they would have something built-in for something so simple. $\endgroup$
    – Abrobot
    Jan 8, 2022 at 5:15
  • $\begingroup$ @Abrobot well… it’s actually not that simple. It is simple if the assumed case is made up of all right angles, but that’s getting really “special use”-ish, and general purpose tools would be much more flexible while being only a bit more complicated to use. $\endgroup$
    – TheLabCat
    Jan 9, 2022 at 5:11

Here's what I would do.

  1. Here's a replica of your mesh.

    Enter image description here

  2. Select the bottom vertex in Edit Mode as shown. Hit N on the keyboard to bring up the properties menu and click on the Global. Copy the Z of the vertex.

    Enter image description here

  3. Select the bottom left two vertices and extrude them along the Z Axis by pressing E and Z consecutively. The location is irrelevant.

    Enter image description here

  4. Don't select any other vertices. Go to the Z in properties menu and paste the copied Z value from step 2.

    Enter image description here

  5. Now, fill in the faces by selecting the corresponding vertices and pressing F. Repeat this for the underneath and back of the mesh.

    Enter image description here

And that's it. You may want to delete the residue vertices from before, but that's completely opinion based. I wouldn't, so that I have more control over the mesh.

  • $\begingroup$ As with Ribbit12's answer, the resulting geometry is non-manifold due to 2 internal faces (edges connected to those 2 internal faces are connected to 3 faces, while in manifold geometry each edge is connected to exactly 2 faces). Not that it makes it wrong, but many tools like subdivision give weird results (and spawn questions here on BSE) due to non-manifold geometry. Of course removing those faces is a trivial task, you can select them in wireframe/x-ray mode and remove. $\endgroup$ Jan 8, 2022 at 11:59

You can make walls without thickness and then add the Solidify modifier with the Even Thickness option checked:

Enter image description here

  • 1
    $\begingroup$ I actually thought of this, but in this case, I wanted the corners for later. Also, I just wanted to know the answer to learn how, but that's for the comment. besides that, how did you know the exact shape of my building? $\endgroup$
    – Abrobot
    Jan 8, 2022 at 5:19
  • $\begingroup$ It's less time consuming to cut corners with knife tool with angle snap and cut-through enabled from top orthographic view after applying the solidify modifier. $\endgroup$
    – 3dFigaro
    Jan 8, 2022 at 5:30
  • $\begingroup$ Cool, ill keep that in mind; thank you! $\endgroup$
    – Abrobot
    Jan 8, 2022 at 13:57

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