Bend Distortion

I’m getting some distortion in the outer curve representing a constant cross-sectional area bent along a Sine wave shaped curve. I’ve used the command before with no problems.

The options used are: Point to bend through ( Copy=No Rigid=No LimitToSpine=Yes Angle Symmetric=No PreserveStructure=No )

Please see attached. Can anyone spot my mistakes and suggest remedies?Points_to_bend_through.3dm (37.2 KB)
Object_to_bend.3dm (93.6 KB)


I’ll take a look but I’d maybe try Flow rather than Bend here.

@saucerdesigner - one problem is that the object is thicker in the area of the tightest bend than the radius of the bend so you get some self intersection.

Object_to_bend_PG.3dm (234.6 KB)


Thanks Pascal. I tried Flow. That’s amazing. A huge time-saver. I’ see a kink at the transition from Sine wave to circular arc, though. Do you think it’s because I chose the start of the target near the beginning (top left) of the Sine wave and the end near the end of the circular

arc segment?

Hello - the ‘kink’ is an overlap/self-intersection due to the object being wider there than the radius of bend. The solution would be to make that bend softer there - larger radius than width of your object, or make the object narrower there - less that the bend radius at the corresponding location.


Thanks, Pascal.

Hello - Lengthening the sine wave helped with the kink, but now I’ve got some weird extra curves I don’t want. I don’t see an option that might have caused it, such as “both sides”. I elected not to copy, still no joy.

  • David

Hi David - see if this is more like what you want -

Object_to_bend_PG2.3dm (530.2 KB)

@saucerdesigner - updated to V5 format.


Hi Pascal - I only have Rhino 5. I can’t read your file.

Hi Pascal, I’m having trouble incorporating your mods into my model. I loose the control point you mention. How did you get Flow to behave? Pilot error on my part, no doubt.


Hi David - I replaced your s-curve (lots of points) with a simple four-point tangent blend between the line at the top and the arc. (The original is there but locked)


Hi Pascal - I couldn’t get it to flatten by dragging the control point when nearing the X-axis. I’ll try to duplicate your steps (replace s-curve with simple four-point tangent bend).
Thanks…I appreciate your help.


Hi Pascal - I finally got Flow to behave by reducing the number of divisions in the target curve. I appreciate you.

  • David