How can i make a path like this

I need to make a pass/walkway like this in Rhino and I just have the level height of some points.
already tried splitting path to smaller curves and make it by sweep but the result is not satisfying.
Any recommendation?what command do you suggest for adjusting the leader curve?



Have you tried the CurveThroughPoints command?

If Starting from the beginning:

I’d probably use the Curve command for this to sketch out the general path shape… which for this part would only be a 2D Plan View of the path. (e.g. all points on the same plane)

Form there try using the PointsOn command and adjust the Z axis on various points until you get the climb/slope that you’re after.

Take a look at the SetPt command as a way to match point values by x,y,z axis.

Can you upload your Rhino file so I can take a look at what you have. I’m using Rhino 5 for Mac, so please export to that version if you can.

Treetop.3dm (7.5 MB)

Thanks for your reply.
actually its part of a big real project and we already have the 2D lines.
I used gumball to relocate the base points in desired height but the points in between are not locating in good locations, so the shape is not good.
The attached file includes 3 different version of the path I tried to make.

Thanks for uploading a file.

IF you’ve been adjusting Z axis with the Gumball… and applying that to a path which has been ‘Split’ or ‘Exploded’ (into smaller curves)… then I think that’s adding in a lot of additional adjustment points, with a lot of room for manual edits just to get smooth fluid curves.

It seems to me that a single curve to define the path… can be followed up with the Sweep1 command in order to get the profile contours of the walkway to follow along the general reference curve.

If by chance you would be looking to have changes in the width of the walkway (such that it subtly gets wider, or more narrow)… then Sweep2 applied to two curves (that define the changes in walkway width) would be the way to go.

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Thanks for your help.
Actually I was looking for a way to adjust the single curve line in a easier way.
I will try your recommended way again.

If you Need and Want to keep your existing 2D paths Exactly as they are… that’s completely fine.

There is still room for a hybrid approach here… where you can draw in a new Curve and use that for controlling elevation changes along the Z axis.

Run the Sweep command to generate the walkway (making it a little wider than normal)…

And THEN use your original 2D Path Curves as ‘cutting edges’ for a Split or Trim command… in order to trim back the results of the sweep commands oversized walkway to equal the 2D paths you originally had.

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hello @sepideh.payami

I have prepared a file for you because it is hard to tell with words but basicly what i did is;
-find the center of the path between flat surfaces,
-measure the length of that curve,
-drawing same lenght line
-move one end of it to see the incline.
-after that spliting it by the lenght of each individual arc
-find their start and end elevation
-moving both ends and between points accordingly.

it is complicated by writing but you will understand it in the file.

By the way i needed to change a curve, it was not tangent. you will see which ones

have a nice day


treetop_path.3dm (330.1 KB)

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In a lot of ways this looks like a circular stairway, with out the steps. Same kind of issues of rise and run, with the added challenge of not really being a circular shape in plan view. A couple of thoughts… 1) model it as if it were a circular stairway, with the leading edge of the steps radiating out from a common center line. Make it wider then the furthest out point ( the outer radius) and the inner radius smaller then your inner most point. you could then adjust the intermediate “rays” (leading edge of the steps) as needed for a more organic shape. 2) use the “analyze_curve_curvature graph on” function to see how “fair” your curve is. Use control points to adjust for a more fair curve. I have also had good luck with the fair command in combo with the rebuild command. The curvature graph really helps to see the smoothness of your curve. Time spent producing a fair curve allows all of the subsequent steps to flow smoothly. (pun intended) We do quite a few of these kinds of curved projects. If you want a little more in depth help, send me an email. I can help you out.

Bill Amaya

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do have preferred z values for your points?

Thanks for the complete and helpful reply, specially about the file.It helped a lot and I will definitely try it.
Thanks again

Thanks for the clear explanation.
Honestly I haven’t looked it this simple (as a stairway), It`s easier now to deal with the shape.