How to find the framing work on a complex 3d shape

Dandun · November 6, 2019, 4:13am

Hey!
So far i have found creative ways to get to what i wanted but since with time the objects or shapes i create are getting more and more complex im really breaking my head on it.

So is there an easy way to find the frame work of a complex 3d shape? My shapes are built from triangles most of the time (geodesic dome style) and i would like to know how to get the measurements of the boards i need to cut in reality so i could build it.

I attached a photo of my latest shape.

If anyone have an idea please help!

Thanks for your time.

Dandun · November 6, 2019, 4:14am

An example for what i mean with framing work.

Box · November 6, 2019, 4:51am

Do you mean something like this?
Tig’s Smart offset then Fredo’s Joint Pushpull.

Dandun · November 7, 2019, 1:12am

So its works in simple shapes. But not on complex one. Other idea?

Box · November 7, 2019, 1:13am

What!?

Dandun · November 7, 2019, 1:14am

The shape that is in the picture its not working. The triangles get all wired. Maybe its not possible to frame a shape like this? I donno.

Box · November 7, 2019, 1:15am

Attach the model if you want specific help.

Dandun · November 7, 2019, 1:22am

here
flower3.skp (252.9 KB)

Box · November 7, 2019, 1:40am

I get this.

Dandun · November 7, 2019, 1:42am

Mmm not sure if it works. Could you upload the file?

Box · November 7, 2019, 1:48am

You need to be specific about your frame sizes, I just did it randomly.
flower3Box.skp (1.1 MB)

Dandun · November 7, 2019, 2:05am

Yeah it looks right, but once you look deeper in to the triangles you see they are impossible to build. Its like the boards will have to be twisted and different thickness on top and bottom. Donno if you understand what i say…

Dandun · November 7, 2019, 2:08am

that will be correct but i will have to put spacers in the back between the big pieces and by that im loosing strengths on the structure.
maybe it is just impossible to do. flower3s.skp (230.9 KB)

Box · November 7, 2019, 3:09am

What about this, Since the design is symmetrical I have taken one section and made it into separate straight frames. You can see how they interact and adjust them to fit. Depending on your boards. Then array a full set. Without the innermost triangle you could even reduce the number to be modified by half again. Or flipped components instead of the groups I have used. So for this specific shape you would need to adjust 15 to get the 464 needed.
Individual frames.skp (119.2 KB)

Dandun · November 7, 2019, 4:23am

I have tried to find the frame work on the separated pieces like you suggest here.
you can see on the file i sent on a the message above what happened.
i dont really understand how can i adjust them to fit like you said. in the sketch you send they are all connected on the bottom but there are spaces on the top and thats not what im looking.

Actually i think that it is geometrically not possible on that specific shape. and thats why we are having hard time to do it.
or maybe i need to try and get to this shape differently.

thanks for your help though!

Box · November 7, 2019, 4:28am

Yes, the shape you want is impossible with square frame sections, so by making the square frames you can see where you need to slice them to make the fit together.
If we are talking timber, they need to be wedge shaped and mitred. So by positioning each frame push pulled naturally you can see how to fit them together.

To make each, I double click each face and make it a group, then extrude it.