Example of Split Commands

Hi Folks,

I have a shape I made by using the RailRevolve command.

After creating that, I drew in a line and positioned it under the shape so I could use it with the Split command in order to divide my shape in half.

The results of this surprised me a little bit—so I figured I post this message just in case it’s useful as troubleshooting example for the Rhino developers… (even at the risk of them already knowing about it (probably).

However, I’m not trying to make a big deal out of this,… the results don’t block me from being able to move forward with my modeling. So I’m not necessarily looking for a way to fix this for my purposes.

If by chance this a well know issue, and it cause might happen to make me a more informed Rhino user… then I’d be happy to learn about the underlying reasons why these results come about.

SplitCommandExample.3dm (3.2 MB)

Hi Jim - yep - all closed surfaces - this one is closed in the ‘around’ direction - have a seam - the ‘extra’ piece is from that - it falls inside one of the halves. In Wirefrtame you can see seams - they draw extra thick like edges.


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Thank You, Pascal,

That makes a lot of sense, so in the future I can use the seam direction in my favor if I only wanted two equal halves.

As it turns out in this example… my next step was going to be to split one of the halves into 2 quarters… so I ended up getting that for free this time.

… with the added excitement of thinking I also discovered a hidden secret about the software. :slight_smile: which I have to admit is always kind of fun. even though the likelihood isn’t so great.

Anyhow, Thanks Again, Pascal. That’s a great explanation.

Take Care,


Use the SrfSeam command to move the seam in closed surfaces. (I use Rhino for Windows and have not verified that Rhino for Mac V5 has SrfSeam.)

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Thank You, David.

I just checked for it and it IS available on the Mac version, so I’ll test it out now.

I really appreciate your input for anticipating how this command can better help me in the future with this type of modeling task.

Take Care,

Jim D