Does opposite of chain edges exist, picking curve segments yet curve is continuous?

Rather than have to split curves for when a curve forming one edge/rail is only partly needed for another rail, can one select an option in Sweep1 or Sweep2 so as to then pick at a curve and have rhino see its original parts before it was joined, or even identify in an unjoined curve segments of it that might be useful in the rail, seeing where the curve passes through adjoining curves Int points, so as to form together the parts needed for a rail, yet have that curve remain intact before and after the sweep1 or sweep2 command is run ?

Also NetworkSrf has no chain edges or even my opposite of such , one has to create edges dupEdge, joint them duplicate them , split them for each part of the structure. What I use for one area needs splitting aor parts adding to for another, gets very duplicated at times.


I set up or more layers with Temp in the name and usually a variation of purple/magenta in color. I put any temporary curves, etc in these layers to keep it separate from the primary geometry.

I think you can only currently get one segment of a continuous rail if it is an edge not a curve and you used SplitEdge on it. MergeEdge is the opposite if you need the edge to be seen as one again. As for NetworkSrf, type Chain and press enter when asked for the curves and you’ll get options for chaining a selection.

Just keep in mind that NetworkSrf cannot offer continuity better than position on chained edges.



If this has the ability to pick ones way along a curve that hasnt been subdivided, assembling the bits as one goes, I am in heaven.

As david says, for the moment one has to create a set of all the possible combinations of curves needed when surfacing something, much use of split etc.

drives me nuts, I wish to pick into one curve set and create various sets. keeps it all simple.


I’m not sure I follow, is there a sample file you can post with the curves you’d like to select with chain when using NetworkSrf?

Hi Steve, you might try SubCrv. But this does not work as a nested command. However, for the Sweeps you do not have to subdivide the rail curves. Rhino does this automagically based on the first and last cross-section.


Hi BrianJ
attached a fictitious example, in which only lines need segmenting.

one is expected to surface item C, line 1-3 one finds is drawn and is of use for c1, but will need splitting to become 2-3 for a sweep2 for C2

I would like it that one can click on 1-3 in the region of 2-3 and rhino just uses 2-3 without user need to clone and split curve at 2.

Likewise item B, a sweep2 or maybe a networkSrf, required 7-9 to be split at 8 so as to have 7-8 to use as rail or profile.

Item D, requires 5-6 split at 5a to use as profile.

4-5 needs 4-11 and 10-11 segments making from it.

To be able to keep 7-9 intact and pick between 7 and 8 and have rhino temporarily use that segment yet not in fact cut the line, or require user to clone and split it at 8 is my wish.

In reality the items are more complex, and having arrived at a very busy cobweb of curves, to have to clone them sometimes 3 or 4 times and segment them for use on surfaces they all contribute to in different ways adds to the muddle.

Fictitious indicator of segment selection wish sweep etc.3dm (105.8 KB)

There is no reason to use curve network surf to create this object. It just adds unnecessary complexity through approximation. I never use it.

Here are the commands I used. Solid extrude curve. Sweep 2 rail. Surf extend. Surf Planar curves. Create solid. Boolean union. Solid merge all faces.

This is super basic stuff. The forum is here to help people when they get stuck. Not to walk them through the basics because they refuse to make any effort to learn.

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Here’s how I’d have the curves set up to use NetworkSrf for both surfaces. What I like about NetworkSrf is that only the interior area encompassed by the set of curves is surfaced. In this example you would just need to explode the outer border not split the curve you hoped to avoid splitting.
Steve1_crv_split_needed.3dm (239.4 KB)

You don’t need to split 7-9 here the cross sections (arcs) stop the Sweep from going higher and NetworkSrf also only surfaces the interior.