# Perfect 45 deg mitre ( 22.5 joint cut ) between two objects

This is a precision modelling question which I'm hoping has a somewhat updated answer. Historical suggestions either seemed too complex or haven't worked as expected.

These objects are identical in width and height, and consist of only outer and top faces.

The intuitive approach would be to have the knife snap to the intersections of the two objects ( in top view ), and draw the cut line between these snap points. This doesn't appear to be available in 2.92.

Is there a quick and easy way to accomplish this? Grid snap is of no use, as shown in the maximum close up of one of the intersection points. I've tried all manner of other snap options but I'm either doing it wrong or they refuse to activate.

There are other ways to do this, but here's one that I use a lot when I want this kind of precision. This will give you a miter cut. It will work for any miter angle. It assumes you have already placed the two pieces how you want them. You can modify vertex placement to get other results.

This technique relies on

• Subdividing edges
• "Edge" (in this case vertex) slide
• Snapping vertices to edges on other objects
• The knife tool.

If you need a refresher on how to use them, see below. The first part is only a step by step to reshaping the pieces.

## Step by Step

This is the best I can do, using 3.1.2:

• Set Snapping to Edge and turn off Project onto Self

• Select the object that is at the angle. Cube.001 in your example. Plane.001 in mine

• In edit mode, select one of the long edges.

• Subdivide that edge.

• In vertex select mode, slide the vertex created by the subdivision until it snap to the "outside" long edges of the other object. (I've exaggerated vertex size in preferences to make the snap point obvious.)

• Repeat for the other edge.

• Go to top view

• Use the knife tool to create an edge. Type C to enable cut through. The knife tool will snap to vertices, so start at either and go to the other.

You can remove the three "waste" vertices giving you the bevel on that beam.

• Switch objects and do the same for the other beam.

At this point you could join the two objects; select all of the vertices; and merge by distance to get a single object.

## Tools Used (all in edit mode)

• Subdivide edge

• Select the edge to subdivide
• Type CtrlE to bring up the Edge context menu
• Select subdivide from the menu.
• Edge Slide

• Select the vertex to slide
• Type GG to start the slide.
• Move the vertex to where you want it.
• Type Enter to accept the slide.
• (Because we're using snapping, a circle will appear when the vertex is near an edge. If you accept the slide at this point the vertex will jump to that edge.)
• Snapping is enabled with the snap menu:

• To toggle snapping on or off, type CtrlTab or push the button with the magnet icon.
• For this, we want Edge snapping enabled.
• To avoid complications, disable Project onto Self
• Knife Tool

• Type K to start a cut.
• Type C to enable cut through. This will continue the cut down the side saving having to do extra cuts.
• Move the tool to a vertex. The green box will have a red outline if the tool has selected that vertex.
• Left click to start the cut
• Move the tool to the other vertex.
• Left click to finish the cut.
• Type Enter to finish using the knife tool.