how to create a spiral hemisphere with the same distance

jan_hendrik_hellmold

Hello everyone,

I would like to create a spiral hemisphere with opposing spirals as shown in the picture. However, the special requirement is that the distance between the two spirals or between the revolutions should always be the same. 

When I create a spiral with the Helix tool, the distance on the planar plane is always the same. As soon as I project it onto the hemisphere, it is logically no longer always the same. (as can be seen in the picture).

Is there a feature or a workaround that I don't know that can solve this?



https://cad.onshape.com/documents/45dba9a13797ddb80d90e967/w/448939e33b89713aacf14704/e/9090cba823a3cded292c81c8

Thanks for any help.

_anton

Really easy with Parametric Curve, see Parametric Curve 4 in https://cad.onshape.com/documents/578ff8b3e4b0e65410fcfda3/v/69f7db3196182c708f8e4835/e/46b903b8bff0b36927baa2a6

You just need the polar angle (phi in the custom feature's convention) to be linear with the input parameter.

glen_dewsbury

To allow others to see the document for your link it wants to be made public.

martin_kopplow

Maybe a job for Caden's FS?

https://fs.place/Listings/UIRNFHJ92YPIN3FAUCAJQJAXD7FUPT5L

_anton

Really easy with Parametric Curve, see Parametric Curve 4 in https://cad.onshape.com/documents/578ff8b3e4b0e65410fcfda3/v/69f7db3196182c708f8e4835/e/46b903b8bff0b36927baa2a6

You just need the polar angle (phi in the custom feature's convention) to be linear with the input parameter.

jan_hendrik_hellmold

Thank you so much @_anton thats exactly what i was looking for.