How to make a birdsmouth

Hello. New to CAD and Shapr3D, but having a blast. I’m designing a wood & storage shed, with a mono pitch roof. The roof joists will be 2x6s sitting vertically on a 2x4 double top plate. I want to design the birdsmouth cuts into the underside of the vertical 2x6s, so they rest on top of the 2x4 top plate - but can’t figure out how to do it. I know how to copy and use the Pattern tool to repeat them once done. It’s just getting the first 2x6 birdsmouth correct.
Talk to me like I’m a 3rd grader struggling to progress to 4th grade… :smiley:
Thanks in advance!

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Welcome to the forum.
I made two 2x4’s (1-5/8" x 3-5/8") and an angled 2x6 (1-5/8" x 5-5/8"). I did not include the fillet radii on the pieces.
Place the 2x6 on the two top plates and do a Subtract. After that you can use the Pattern tool to make copies of the 2x6. I spaced them 16" apart in this demo. Hope this helps.


A short awncer, If you have the wall framing up, you can place the rafter where you need it and use the subtract tool.

Or you can use a rafter table and do it just like you would in real life. Whenever I do stringers I do it just like I would in real life. And then use the align tool. You can then use the pattern tool to add the additional rafters.

Also I use shapr as an onsite calculator from time to time, it’s really powerful for getting sq footages. Just don’t bring the nice iPad


As a visual learner, the video was perfect for me! Thanks for taking the time to do that. Works perfectly now. Cheers!

A lot easier in Shapr than in the field, unless your only job is rafters. And often on track home projects you have a small crew who’s only job is rafters. You have a stairs guy or two and a couple layout guys. That was the old way. The new way is all prefab.

Glad to help. I too am a visual learner and definitely a ‘right hemisphere’ person.
Reach out if you have any other ‘how to’ questions regarding Shapr3D.

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Well. My next project will be interesting then. Building our own home (doing as much of the work as we can, ourselves). No significant construction experience - and no, I don’t have a death wish:D

If it’s your first, best not to build it for you, but rather for potential buyers market. Mistake a lot of people make and run out of money near the end.