Unexpected results with sketchwrapper unwrap

robert_scott_jr_

Hello all. As a new user, for a couple of weeks I've been trolling the internet relative to Onshape, seeking to discover what Onshape wants me to do to accomplish tasks. Its been frustrating at times but I suspect it's because I haven't got a grasp on the logic needed. This morning I am trying to do this: https://cad.onshape.com/documents/c3d6b3810dd5647047724aaf/w/cf6f2bc462daa0247cb06ad6/e/a79bb0615730c0538a156322
on this https://cad.onshape.com/documents/0027ef5487d62044f4fb03c2/w/cdc30009e74f1a00699322c9/e/d43fd7d9ea180a5f81a3d97d
 At first I tried it with the cylinder sans gap but it didn't work and I kept getting warnings about deselecting parts. After creating the split in the cylinder, unwrap worked but instead of getting the results similar to the first link, what resulted with my attempt was two perpendicular lines. What am I not getting.

I'm impressed with Onshape. I'm what you might call a tinkerer (even more so having discovered the enabling world of Arduino about 6 years ago) and can't see needing the pro version of Onshape. To create this tool (Onshape) must have required much time and work and I can see that it goes on. So Thank you very much! I would also like to say thank you with a contribution. Please point me in the right direction.

- Scotty

P.S. Hope I've posted this properly. Please offer advice if not.

konstantin_shiriazdanov

you did almost everything correct, but the split of the cylinder should be as symmetric as possible, or Sketch Wrapper wouldn't know which side of the face should be unwrapped to which side of the plane
https://cad.onshape.com/documents/379e5044b8e552bd14867599/w/8780ceee0617da8b85b23ba5/e/69163ddb8f7c2a572049b53d
you can also use builtin sheet metal functionality to unwrap cylinder faces, just set K-factor to zero

robert_scott_jr_

Thank you for responding. I couldn't grasp what you you meant about the split being symmetrical since the split of your model seem to be the same as mine. Additionally,  I didn't understand "Sketch Wrapper wouldn't know which side of the face should be unwrapped to which side of the plane". Perhaps it's because I interpret a face to be two dimensional and so one side a face is just a mirrored image of the other side. I was able to fumble my way to achieve a correct flattened image of the cylinder by following the features in your model but I only mimicked the features without coming to understand the concept of how to do it. I did turn to sheet metal functions and that route was fruitful.

- Scotty