R6: Project Curve against Curve

Hi all,
I often move curves into close contact with other crossing curves and I find myself doing this very often. But moving (adjusting) curves to connect with other curves (MatchCrv, SoftEditCrv etc) isn’t always trivial (difficult to see with the naked eyes if they are in contact or not). Often I resort to make a surface to Project my curves against, while it had been simpler to Project the cruve against an existing curve.

Why isn’t there a ProjectCrv?

I would suggest to introduce a Project against curve command for R6.

// Rolf

Using the near snap will ensure that your curves are in contact after moving them.

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From what I’ve seen of your modelling examples you already have some surfaces… One tip is to use the ExtractIsoCurve command and then use the blend curve command between the two ends to build your network. Blending the curves as either tangent or by curvature will give you a neat surface. What you may find is you’ll end up working yourself into a corner where two of three surfaces need to be connected and you’ll chase your tail with blending and matching but that’s all part of the learning process… If you don’t want to pull your hair out, buy a stress ball :smiley:

In all seriousness though my old Autodesk mentor back in the early 90’s said “If it seems like hard work and you think ‘there must be an easier way’ - usually there is”.

You can project a curve against a curve by the way… it creates a point where they intersect depending where the CPlane is and what view you’re in.

I think I’ve developed a kind of Stockholm Syndrome with Rhino… You love it, then you hate it then you depend on it.

I wonder if version 6 could have a time log for list of commands you’ve used?

“Andy - to date you’ve used 46% of the available commands in Rhino in the X years you’ve been a registered user”

I always wonder if I would get over the 10% mark. Old dog and new tricks and all.

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Yeah I hear that. It would be a sobering acknowledgement. I guess I’m counting the times I’ve used a command but not understood it or got the correct outcome :smiley:

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Hi Rolf - one tool to add to your arsenal is HBar - you can use that with the Perp Osnap to move a curve to intersect another- the problem may be that it moves another part of the curve more than is acceptable - it has to work with the existing control points. You can also make a ‘live’ network of curves by setting up something like in the attached file - I don’t know how often it would be worth the effort, but perhaps- point-edit the blue curves to update the network. The black curves are CurveThroughPt on points which are intersections of the blue curves and a set of planes. All with History.

CurveGrid.3dm (112.6 KB)


Useful in some cases yes.

I often find myself changing view as to pick an intersecting point, ensuring that I don’t move the curves in the wrong directions. But Near Snap will definitely be useful as well. Thanks for pointing that out.

That’s a good advice. I’ve used the ExtractIsocurve & BlendCurve approach for making cuts and complex intersecting fillets, and powerful as it is it can be used in many other situations as well. Thank you for drawing my attention to this.

This was some “missing bits” for me - The Perp Osnap will definitely add to my tool box in this context. HBar was new to me and may be useful as well.

Distinctly Orthogonal and/or Aligned
Most important for me is perhaps not fully “free form” though, but rather distinct curves which has well defined curvatures in orthogonal directions, so although Perp Osnap will be useful at times the command will probably tend to disrupt the “orthogonality” or alignment of some basic “guide curves”.

Curves from From Solid Edges
I’ll be back later with some examples of what I mean. However, tricky curvatures can be approached in different ways, and one way I’m currently exploring is to make solids and extracting Intersection edges/curves from them (also after some basic “Pipe cutting” and BlendSrf between the surfaces in the splitted solids) as to gradually form at least the most basic curves for networks, and from there on, forming other surface details by handmade tweening curves adjusted with ControlPoints, if need be. Aso.

Persistent luck
As I learn more existing commands I’m getting better and better at making complex shapes, so I keep trying. As one Swedish world class slalom skier (Ingemar Stenmark) said when asked how much his success depended on chance and good luck, he replied: “I may well have had lots of good luck, but I’ve noticed that the more training I perform, the more luck I seem to have:pensive:

I appreciate your help very much, and I must say I’m impressed by the help provided by the rest of the community as well. Many thanks to all of you out there.

// Rolf

“Chance favors the prepared mind” - Pasteur

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OK, off with the gloves.
“Luck is what happens when preparation meets opportunity" -Seneca

Wait, there’s one from Lucille Ball as well.