Desperately need help with this please

Hello, I have been struggling with creating a wavy surface for a wheel, as per the photo. in the attached model, the large circle is the outside edge of the wheel which is planar. The red circle is the top of the wave, whilst the lower edge of the hub is the bottom of the waves. There are 3 high points and 3 low points, all equal in size and orientation.
Any guidance/direction as to how to go about producing this would be greatly appreciated.
Many thanks,
IanRoadwheel 2 forum.3dm (72.7 KB)

Hi Ian,
hard to see in your picture, maybe Loft?

You might want to rebuild your curves with 30, 60, 120 pts.

Thank you Ferry, but the “waves” do not run right across the radius. They are flat where they meet the outside rim. You have given me another approach to try, however. :grinning:

Loft is definitely the way to go, but you can just use the two curves (a), the outer flat curve and the inner one. Creating the inner curve is more of the challenge. I have tried to make this in Rhino without success, but using a sine wave in grasshopper seems to work (however I do not know if you’ve used grasshopper before). I include the definition here, but you can also probably just scale (use ScaleNU) the ‘baked’ curves in the attached Rhino file if that helps! (7.8 KB)

WheelCurves.3dm (114.2 KB)

The image (b) shows how I would personally do it, lofting in the other direction through a series of lines made between the two outer curves. This does require a bit more grasshopper. It might create a slightly smoother result, but to be honest the first one might be sufficient for your purposes and with the scale trick, you won’t need to use Grasshopper.

Best wishes,


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Thanks very much John, I’ve not used grasshopper before so will play around in Rhino a bit more, now that I have an idea of how to go about it.

Kind regards,


No problem, Rhino does have a helix command that will follow a curve but as far as I know, nothing to make trig functions that follow a curve. Like I say, scaling the curve using ScaleNU made in the Rhino file I attached should be sufficient before the loft. Best of luck with it!

Had a go using just Rhino. Could probably use more time getting the tangency constraints better using those extruded red surfaces.

Meh - create the 3 up 3 down curves. Interpolated Curve through the 6 inside points. 2 Rail sweep.

I cannot open John’s Rhino model for some reason, and am struggling with establishing the 3 up 3 down curves. Once I can do that, it is plain sailing.


Create the outer circle and the inner circle. Draw a line between them. Polar array the line (6 times). Turn on control points for the lines, grab every second inside control point and move them up.

What version of Rhino are you using?

Rhino 5

That would be the problem. Find attached R5 version also with the curved moved to your geometry. One thing to mention is that your inner shape is tapered, so you have two choices. Either you can project the curve to the inner surface before undertaking the loft (using the Pull command or otherwise), or you can generate the loft and then trim it.

Roadwheel 2 forum_edit.3dm (167.1 KB)

You can also go for @ftzuk 's method to draw the curves, depends if you need it like a sine wave or not (I just assumed that you did looking at the initial picture).



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Awesome! Thank you. Yes, it should be a sine wave. The tapered hub was giving me a lot of grief.
Many thanks to all.


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