Trying to make a fluent double helix

Hello everybody,

I am trying to recreate an artwork. it’s an illuminated “ribbon” in and around a tunnel in Eindhoven in the netherlands.

The problem is the turn just outside of the tunnel. I can draw a helix but I cant get it to fit the other pieces and be fluent. I also want the width to be 1 metre.
This is what I have so far:
Montgomerytunnel.skp (20,4 KB)
Any help will be appreciated greatly!

Thanks, Herman.

ex: zwerm.skp (2.2 MB)
First, search on Google and try to find the name of this bridge (Zwerm-Eindhoven-The Netherlands). After that see if you find any plans;

Then use spline from Fredo6: Bezier Spline and Fredo6: Curviloft for the shape


@mihai.s Thanks for the video, but it explains pretty much everything exept for the bezier spline part witch is the very part I am having troubles with…
I cant seem to find a good tutorial of bezier splines.
All tutorials i can find are about 2d curves/splines and not in 3d space…
If anyone knows any please let me know.

Thanks again, Herman.

@mihai.s Did you draw the bezier spline in 2d first and after that “pulled” it into 3d with the controlpoints?

  • After you start a spline press the Shift key twice quickly to toggle between ‘Start/End points’ or ‘Open-Ended’ modes;
    Draw the spline in 2D plane and modify to 3D
  • Use Arrow keys to lock on Axis or Plane;
  • Use Ctrl key to toggle lock Axis and lock Plane mode.

Watch very good tutorial about Bezier Spline

\ I drew those dotted lines just because if I kept the image as background the size of the GIF would be greatly increased.
\ Fredo, please make those grip points bigger and less sensitive, so as not to lose them easily. Thank you!

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Thank you very much @mihai.s!!
This video explains very well how to “fit” the bizier spline to the shape that you actually want!
I already watched that tutorial but couldn’t extract from that what I needed.
Will try it later, have to cook diner now.
Thanks again, you’re a lifesaver!!

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