Solid editing is still very lame

Where is the great core overhaul that will allow to do simple solid edits such as the one described in the following file ?
Solid Editing just got — the same as before.3dm (72.2 KB)

I find solid editing very useful… 2 degree surfaces such as your cylinder behave pretty strangely. You can explode and rebuild the side of the cylinder with a 3 degree surface and perhaps more control points. This makes your transformation work fine. I know this isn’t your point and agree the current system doesn’t seem as foolproof as I’d like it to be.

The above sounded preachy. I agree the manipulation you showed should be a given and its strange to explain to a beginner why it wouldn’t work.

Hi Alexander, the way you state it is excellent : “strange to explain to a beginner”.
Here’s another one, with curves :

How would you explain that one ? How about :
“For some obscure reason, It makes the life easier for the programmers to raise all the sub-curves of a polycurve to the same degree, so don’t forget to explode it if you want to edit the corners while keeping straight segments, and don’t forget to join them back again afterwards”.


Or: “You’ll have to preselect the polyline, explode it, then turn on the control points, select the points you want to move (making sure you’ve got any coincident points), move them, then turn the points off, select all the individual bits or SelLast, and join them back up to get back to where you started. If you don’t bother to explode it first, you’ll screw up the curve geometry.” All to nudge one of the straight line elements a couple of mm. Explaining that to a beginner doesn’t exactly fill them with confidence or enthusiasm. The silly thing is that using Solid Point editing on a shape made from the same curve doesn’t suffer the same malaise, for simple edits at least.

In many ways, you’re better off joining it all up to make sure that it forms a closed curve, then exploding it and grouping everything. Point editing then behaves more like a beginner would expect. You just have to remember to Join everything before extruding, etc…

Part of this is the price to pay for being able to join spline geometry to polyline and arc geometry - something that say AutoCAD doesn’t let you do at all. However, that said, I agree that this is confusing and annoying, the Rhino polycurve paradigm is old and needs to be revised for elements composed with lines and arcs. One should be able to edit straight line segments in polycurves by moving their endpoints (no points should show up in between); arc segments of more than 90° should not have kinks at the quadrants.

That means somehow keeping the underlying geometry as separate segments while presenting to the user as joined, and converting the geometry on the fly depending on what the user does with it. Unfortunately, I think this stuff is pretty deeply ingrained in core Rhino and will have repercussions far beyond just editing the curves.


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Well, if you need proof that complex problems can be ovecome, check the command line in V6 WIP :
now it can interpret addition and multiplication !
Never give up hope…

There must be an element of this present even in the current V5. If you Extend a straight line or arc to a boundary, the control point structure remains at the same degree, even if it is part of a polyline that includes curves of a higher degree.

Hi Mitch, @MattE and @osuire

I was wondering how complex it would be to prototype this and here is a setup in python that (partially) does what you describe: ( (4.2 KB) )

  • take polycurve segments and present ‘edit points’ at segment meetups
  • let the user select a point and move it (clunky and without interactive preview)
  • rebuilds the polycurve segments

The rule that needs to be set:
How to modify non-linear segments?
I currently apply a morph as a flow over a two lines connecting the initial start and end point with the new ones.


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all this works by simply making a planar surface and editing solid points instead of control points.

So the code is already there, just needs a bit of cut and paste between folders.


Sometimes, polycurves are not planar dear gustojunk.
Interesting, nonetheless.

Yup you are absolutely right. But thinking of examples of polycurve editing I first only thought of 2D drawings, or planar polycurves to build 3D geometry.

Maybe an edit command could check for planarity and they decide what method to use. …Of course maybe all this makes no sense if the team instead drives all direct editing of curves, surfaces, solid faces/edges, with the new subD engine in the background.