Surface array around curved object?

alan_jeremiah

Hi
I'm new to OnShape and not from a CAD background perse so apologies in advance if this is a silly question. 
I'm trying to create a rubber track (think tank track/snow blower track), and while i've created a surface and a single 'tread' (as a separate part) i'd like to copy the 'tread' around the entire surface. When i try and use the linear pattern tool I just get the tread repeated 'x' number of times normal to the face or extend the entire length of a straight face. I'd like it to flow around the entire surface inclduing the two curved ends. 

Any advice on how i might approach this please? 

Thanks
Alan 

henry_feldman

alan_jeremiah said:

Hi
I'm new to OnShape and not from a CAD background perse so apologies in advance if this is a silly question. 
I'm trying to create a rubber track (think tank track/snow blower track), and while i've created a surface and a single 'tread' (as a separate part) i'd like to copy the 'tread' around the entire surface. When i try and use the linear pattern tool I just get the tread repeated 'x' number of times normal to the face or extend the entire length of a straight face. I'd like it to flow around the entire surface inclduing the two curved ends. 

Any advice on how i might approach this please? 

Thanks
Alan 

Is there a reason you made your track rounded rectangle? I assume in real life it is a continuous loop. If you had a circular tread (let's imagine you are 3D printing or injection molding it, you wouldn't want the flat parts with corners molded in) then you can use circular pattern as so:

emmett_weeks

You should be able to use Curve Pattern from the Featurescript examples to do what you want. Just select the edges of the track for the path. You may need to specify a reference direction to get all of the instances pointing in the correct direction. This won't adjust the geometry of the instances created to meet up with the part, so the tread might have to be slightly inset if you want it to intersect with the curved portion.