I'm working on making a triple glazing corner sample, and I want to be able to mitre the profile at 45 degrees so I can duplicate it, rotate it and join them to make an elbow. I've muddled through making the profile, but now I'm stuck on how to get that 45 degree angle.

I've had a look around Google, perhaps I'm not phrasing my question correctly but I cant find any answers. I did try creating a cube to use as a sort of cutting form, but Blender wouldn't let me use a Boolean modifier to do it. Any thoughts?

Thank you!

What I'm trying to achieve:

Corner sample intended result

What I have at the moment:

Corner sample current

  • $\begingroup$ Have you tried the knife tool with angle constraint? $\endgroup$
    – Xtremity
    Apr 11, 2016 at 17:51

5 Answers 5


The way I would miter the corner is to duplicate the elements of the frame, and rotate them 45 degrees around the axis perpendicular to the plane of the glass. Then I would move the duplicate elements so that the bottom of the outside edge of the frame is exactly aligned with the bottom of the bottom edge of the original, and use vertex slide to move the vertices of the outside edge of the bottom so that they exactly align with the vertices of the bottom edge of the side piece. If desired, the appropriate vertices can be merged at that point, or alternatively they can be left as parts of separate elements.

This method need not be limited to 45 degree miters. By adjusting the angle of original rotation, it can be used to create miters at other angles, too, useful in making hexagonal windows, and wagon wheels.


I would suggest using the shear tool to do this.

With the vertices at one end selected go into the side view (shear deforms based on the view) ⎈ Ctrl⎇ Alt⇧ ShiftS and then enter a value of 1 (or -1) to get a 45 degree angle. If your pivot point is set to median then you may need to move the edge sideways to re-align it or you can position the 3D cursor and set the pivot point before shearing.

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Rotate constraint add-on

I usually take advance of the little add-on mentioned in the title made by Ryan Southall to make this kind of job.

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As you can see from the image sequence taken from the script's page on Blender Add-on list, once installed can perform the rotation of vertices for the needed angle with a constrained axis.

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You should probably set the Rotation point to min or max.


You can obtain a quick result using curves.

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  • Make your profile as a mesh
  • Then convert it in a curve : Alt+C then 'curve from mesh/text'

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  • Now add a vertex, and extrude it in order to obtain a first segment
  • Come back to object mode and, again, convert it to a curve
  • Set the curve '2D'
  • And set the profile as a bevel object

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  • Now you can simply edit the curve, and extrude it the way you want

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  • There is no real limitations, except that the curve is 2D (for instance, you can join parts of circles, convert it and join it to your curve)
  • When finished, convert back the curve to a mesh, using Alt+C but this time with 'mesh from curve/...'

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Note that there is no extra vertices added : all is the same as profile extrusion, but that offers an easier way to adjust the whole shape you want to model.


If your frame geometry allows it you could use a shrinkwrap modifier to move all vertices and make the 45 deg corner.

  • Just add a larger plane where you want to cut your frame.
  • Add a shrinkwrap modifier to the frame object.
  • Set Target to your cut plane
  • Select Mode: project
  • Limit to the axis that is along your frame.
  • Select one of directions (positive/negative) to move the right side to the plane.
  • Apply the modifier if you need to.

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