rotate during extrude?

david_lang457

This video shows an interesting gear idea, but to form it you need to be able to rotate a shape during an extrude operation, Is there a way to do this in onshape? I know I can create a helix and sweep along it, but I'm not seeing a way to specify rotation of the shape during the sweep (there is keep profile orientation, but turning that off doesn't seem to do the right thing)

https://www.youtube.com/watch?v=qMDU5tlGUwU

david_lang457

experimenting with sweep, that lets me produce gears that look about right on the outside, but they don't have a straight center like I want.
extrude with rotation does seem like what I am needing.
poking around with things at https://cad.onshape.com/documents/9cd0a5e13fab550343cd0143/w/6bce7c5450780de7d6e3460f/e/1d18f292389f9334d898e683

mahir

Trick is to let the helix specify the twist/rotation. Here's an example below. There is also a featurescript someone wrote that can twist a profile along any swept path. Not sure what it's called though.

https://cad.onshape.com/documents/57acdfaae4b005c413ed9b6f/w/3fd585a46d3af1b3ba413c53/e/f813cd6a214525be95f7ea75

mahir

david_lang457 said:

experimenting with sweep, that lets me produce gears that look about right on the outside, but they don't have a straight center like I want.
extrude with rotation does seem like what I am needing.
poking around with things at https://cad.onshape.com/documents/9cd0a5e13fab550343cd0143/w/6bce7c5450780de7d6e3460f/e/1d18f292389f9334d898e683

There is no rule stating you have to build everything into the sweep. Generate the twisted/helical outer shape using sweep, and create the straight center geometry with extrude or revolve.

david_lang457

when I added an inscribed circle to your sandbox example, it looked like it did the right thing, so I'll need to go back to my testing and figure out what I did wrong (probably an artifact of trying to work with the shape provided by the cyclodial gear featurescript, which isn't centered on the origin, I thought I had accounted for that, but apparently not)

Thanks, and if anyone can find the feturescript to do the twist please let us know (there needs to be a better way to find useful featurescripts and the discussions that are tied to their development than just blindly searching like I've been doing. possibly a wiki of some sort that can organize them?...

mahir

Agreed. Searching featurescripts is hit or miss. Here are a couple interesting FS I found.

https://cad.onshape.com/documents/59007ff281e43510ea3797a2/v/a32c98e33ad3fdfd68973e79/e/8695694c2f658a05d1fb7da2

https://cad.onshape.com/documents/f437577a13ebbc350129b4a0/w/1873523e917e24872187e57a/e/3818058990e621d97e65afc3