Help requested...Inverse of "converttosinglespan"

Rhino
1

Is there a Rhino command that is the inverse of “converttosinglespans” that combines two single span surfaces with a coincident boundary edge into single a 2-span surface?

2

MergeSrf perhaps…?

3

Seems reasonable.

For what it is worth…

  • I have a surface with 2 spans
  • I ran converttosinglespans which gave me 2 separate single span surfaces
  • I ran mergesurf which combined the 2 surfaces into a single selectable entity.
  • Then ran converttosinglespans again, but this time ended up with 4 single span surfaces.

So, something going on there. Seems like it should have returned 2 surfaces, not 4.

4

When you ran MergeSrf you need to use the Smooth=No option. Using the Smooth=Yes option will add extra spans. Why McNeel tries to promote the Smooth=Yes option by making it the default option is a mystery.

1 Like
5

Hello - Smooth=No adds a fully multiple knot; usually, or often anyway users probably would like not to have a kink, is the assumption.

-Pascal,

6

Why Mcneel believes that is the mystery.
It is a given that McNeel has made that assumption.

In the last 25 years the vast majority of postings asking about MergeSrf that I have seen have been where the solution to the problem the user was having was to switch to the Smooth=No option. The current thread is only one of many examples.

As far as I can tell when a user wants to use mergesrf they almost always want the result produced by smooth=no. The main reason for wanting the smooth=No option is that the user does not want to change the shape.

By the way, if you want to get back the original surface you had, you should also remove the multiple knots after using MergeSrf.

1 Like
7

Thank you for all that info…

Pascal… Maybe this is how McNeel intends it, but a couple features here seem a little odd to me…

  • If I have the 2 surfaces selected and click the Surface>Surface Editing Tools>Merge command, I don’t get any options presented. I am not offered the chance to select, or unselect, smooth. It just goes ahead and does the mergesrf.
  • If nothing is selected, then the option window opens where I can select smooth and select the 2 surfaces.
  • Under Surface>Surface Editing Tools>Merge is actually MergeSrf. Seems like the name in this menu tree should be the same as the command, since there are so many different types of merge commands? Maybe it is obvious to some.

I’m on a Mac running v8

8

Hi Matt - yes, some commands just run with preselection - I am not always happy about that myself - a few have been ‘slowed down’ to allow a confirmation of the options - I can see this one could use that massage.

RH-82128 MergeSrf: require Enter to confirm command line options

-Pascal