Building an octagonal roof

Attached is my file for a cat house and I’m trying to get a roof. Its octagonal in shape so i wanted to make plywood wedges that id cover with a waterproofing cover,

I can draw each triangle by hand but i struggled o create one i could copy - i couldn’t rotate it to sit correctly, Also its touch closing up all the gaps between the wedges.

Any shortcuts where i could build one sensibly and just copy would be great.

thanks again guys

house 1.skp (170.4 KB)

Does the roof cover the porch?

If I were modeling a roof like this and wanted to show the individual panels, I would start with an octagonal path and a cross section of the roof panel and use Follow Me. Delete the unneeded geometry leaving just one triangular panel, make it a component and use Rotate/Copy to make a radial array of the panels around the cat house. Note you will need to draw in the vertical edge at the peak because it won’t exist after Follow Me.


Yes that’s exactly it. Some techniques I’ve not used before so i will play about and see what i can get done


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Good luck with it. Your cat is going to have a nice house.

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Remember to raise the walls with the door and window up to meet the roof unless you want your cat to find amusing alternative ways in and out!

well designing and building are two different skill sets!

dont worry - on the list of things to figure out


ok - ok.

so i have the component made but how do i align them. what ever axis i pivot off it leaves another out!!


You need to rotate the component about the center point on the roof. Make sure you reverse the faces–only white front faces should be exposed.

After making the first copy, let go of the mouse and type x7 Enter to make 7 additional copies of the first.

ok cool - after a bit of messing have that done - awesome. thank you again


Other ideas:

but my bank balance is not im afraid. ha

Are you going to put a red light on the outside next to the door? :smiley:

So im here. kinda happy. Im sure there is some nonsense where the roof sits on the walls which i need to fix.

Any thoughts?house 1.skp (507.3 KB)

That looks workable. If you are interested in creating a cutlist, you’ll want to change the component axes so the bounding boxes will align with the part. Here I’m doing it to the roof panel.

What are you building this from? I’m thinking if I were going to make it I would make posts at the corners with grooves to take the side panels. That would make the joinery easier.

i like the post bits - i was going to mitre the sides and glue them (painters tape trick) - then use pocket holes into the base to secure it down and make it strong.

That is the easy way to do it - glue would be strong on the end grain. Was just going to be pine or something cheap from the DIY store.

Thanks for the hint on the cut list. I’ve been making slab tables and things like that but trying to actually design and make some more complicated bits now. Just a lockdown hobby.

End grain glue joints don’t tend to be very strong. If you are using plywood for the panels, you get a little better strength because it’s not all end grain but for solid wood, it’s best to avoid end grain gluing if possible.

Pocket screws into the bottom could be a good option if you can make sure the sides don’t shift while you are driving the screws.

i was going to orientate the wood vertically so the mitre at the angle would be more long than end (i hoped).

If it looks flimsy i was going to add something inside - and then just cap the outside corners to make it look like better joinery. But maybe a change to try and make it better with the pillars and putting some channels in to slot those panels like you said

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