Sheet Metal Cone

kent_henderson

My world revolves around blow pipe so sheet metal fittings like segmented elbows, Tee-Wyes, square to rounds, etc. I know this isn't where Onshape shines yet. And I probably struggle with this more than I should. What is the easiest way to do a sheet metal cone 36Ø to 18"Ø x 24" tall? The link is the aforementioned as a surface. https://cad.onshape.com/documents/31e74c1cfcf618e5e1b92b4d/w/4729d47a0a7ce052732858af/e/abadd0913450663a1b58944b

I need to unfold this.

lana

@kent_henderson
Would this work for you? 

I've inscribed 24-sided polygons into your circles, making sure that perimeter control point is horizontally aligned with the center.
In this model there is no control over number of polygon segments.  If you are satisfied with the approach, It'l be easy to write a feature script with better control.

lana

@kent_henderson
Would this work for you? 

I've inscribed 24-sided polygons into your circles, making sure that perimeter control point is horizontally aligned with the center.
In this model there is no control over number of polygon segments.  If you are satisfied with the approach, It'l be easy to write a feature script with better control.

kent_henderson

Yep. It works. Thank You. I know Onshape's considering additional sheet metal functionality. Inventor does have very useful tools for this along with other blowpipe fittings that might be worth looking at. It even provides an option to roll or bump form. The bump formed option looks like Lana's segmented example and the rolled version is smooth. 

lana

Faceted cone custom feature   generates faceted loft which can be converted to sheet metal model. Please give it a try and let me know if any improvements come to mind.

MBartlett21

@kent_henderson
You can also use this custom feature I just made (it supports whole sketches):
https://cad.onshape.com/documents/896f030ae2c1ef8df7e07d34

lana

@mbartlett21
https://cad.onshape.com/documents/896f030ae2c1ef8df7e07d34
Could you please make the document public.

MBartlett21

@lana
Done

lana

@mbartlett21
It is very nice, but deceivingly flexible: it'll accept any input and the result would not necessarily be  piecewise planar. https://cad.onshape.com/documents/37f19d9c16edeff9601c3317/w/6114098cd84a80ca1a2b9258/e/cca3a41b9c7ff999633b1795
May be restricting the interface to  single sketch, height and scale for the second profile would be a more robust solution. Not sure how useful.

MBartlett21

@lana
It now tells you if there are non-planar faces generated by the feature and gives you an option to fix them (replace with triangles).

lana

@mbartlett21
Very nice.

MBartlett21

Thanks!

oscar_fokker320

This is genius, thanks