Is there a simpler way to model this circular wave geometry?

daniel_bailey

I have modelled a wavy track designed to be a surface on which a cam rides, and is pushed up and down.
See the part in this document:

https://cad.onshape.com/documents/7123abbf4f9c97ed7b66a0cc/w/73e8d2b6da1ef1e5bdadd74a/e/62138605073e04d49c30108c

Currently, to create this part, I have to...
 - create a pair of curves that match the top of the waves on the inside and outside of the tube on which they sit
 - loft these curves down to circles on the base of the tube
 - split the resulting surfaces into pairs of surfaces and draw extra lines between them
 - fill the two areas surrounded by these curves that now define the top surfaces
 - then split, add lines and fill again for the bottom surface

I know the last set of [split, draw lines, fill] could be avoided as that's just a flat disc, which can be modelled in a simpler way, but this felt cleaner and more consistent.

However, I still feel like this a significant number of operations.

I need to make a few of these parts, and wanted to know if there was an easier and simpler way to model them?

(I'm tempted to write a featurescript to generate them, but would be happy to find a simpler way to do it)

Thanks.

NeilCooke

Build the top wavy curves using https://cad.onshape.com/documents/578ff8b3e4b0e65410fcfda3/w/d33395f174e5b38f4abd6097/e/cc0c3d5644a78b1b64d6c3b4#_ga=2.211984855.2125198761.1584664128-1815514980.1584471751

romeograham

Hi @daniel_bailey
I think there's a simpler way.  See what you think of this:
https://cad.onshape.com/documents/73c5480a400eb4a6fc7470d0/w/2e12e7050bff8e2be7e7209a/e/b709d76477291220c8e5ff73

Take advantage of symmetry to greatly simplify the model.


Welcome to the Forum!
Romeo

daniel_bailey

Ah, thanks Romeo, that looks much better than what I had.
Your method also has the advantage of making it easier to change the number of hills on the part (this is handy as the other similar parts I want have different number of hills)

NeilCooke

Here's another way using configurations and FeatureScript. Note that there a couple of "workarounds" that are needed to ensure the geometry is of good quality. https://cad.onshape.com/documents/1a623ed7d5649fb9ebb8e4bd/w/66b1c33b26a0aef8e022c8ad/e/ca3043df46e8fd5677dde519

mahir

One more way to skin the cat. This is based on Neil's configured part studio, but with 2 less features since the goal was simplicity.

https://cad.onshape.com/documents/f5e761d9f30903b94bc9002d/w/1b3939c9c89ab4960668f4a7/e/af0256272776577dd73d6a04

steve_shubin

@daniel_bailey

Here’s a 6 step (Features) method

https://cad.onshape.com/documents/e6b39c5bbe396276e46da7ff/w/d096101996ef685af4aea8f3/e/0de2512de1679398773ff6ef

romeograham

@NeilCooke
@mahir
Those are amazing!

@daniel_bailey If you use these elegant solutions, don't forget that the diameter of the circle needs to be set to #Diameter, or the size configuration doesn't work:





@steve_shubin I like your approach too, though it's not clear to me how it can be flexible - can you add configurations for different numbers of peaks / different height, etc?.

NeilCooke

@mahir the extra steps I took was to ensure that the part was a cylinder (which the loft does not do) and so that the top surface will work with a tangent mate. 

romeograham

@NeilCooke
Ah - I noticed that in @mahir version I couldn't create the Mate Connector (for the revolute) in the assembly on the fly---and that explains why. But the tangent mate still works

steve_shubin

@daniel_bailey

https://cad.onshape.com/documents/9c63b1e34811859f21c4f78d/w/485e3591dfabec7901025baf/e/e4f1e9b4a1b184f126db6a72
 

OK — here’s an easily modifiable way for iPhone users to do it. And it’s also a fairly straight forward way of setting it up. Nothing too fancy being done here.

@romeograham , I’m guessing you could get this method to work using configurations — but I only use an iPhone when doing Onshape. As such, I’ve never set up a config table

I haven’t taken the time yet to take it into assembly. Maybe later today I’ll play around with that. But I did use Create Selection and Tangent under that to make sure the entire top surface was smooth and tangent all the way around

steve_shubin

I took it into assembly to see if the tangent mate would work on the top surface. It does

I didn’t take time to set up a path between the inner and outer edges. I just checked it along the inner edge and outer edge. This GIF shows it running along the outer