I'm making a metal coil as per the picture below by extruding a plane along a spiral curve. I've added Fill Caps to make it solid

I need the coil to look smooth but the top and bottom to be sharp so I have added an edge split modifier and Subsurf modifier.

This works except for the ends of the coil which Blender tries to smooth as well instead of treating them as 90 degree angles.

enter image description here enter image description here

Is there any way round this without turning the curve into a mesh?


1 Answer 1


I was able to create a spiral as you see here by using the spiral addon.


Note that I used 80 steps. This is where you get a smooth spiral without using edge split or the subdivision surface modifier.


The bevel profile object was a nurbs circle that I subdivided and changed into a square. Then I stretched out the square to give me the rectangular shape I wanted. I can give you more details about how I used subdivide on the nurbs circle to make it into the rectangle if you want.

  • $\begingroup$ By the way, @Doodled, here is a screenshot of where to set smooth shading or flat shading. dedwarmo.com/blender-help $\endgroup$
    – dedwarmo
    Mar 6, 2016 at 22:00
  • $\begingroup$ Thanks dedwarmo - works a treat! Its odd that if the bevel profile object is a rectangular plane the top edge is 'bulgy' but if it is a nurbs circle changed to a rectangle it behaves! I found where the shading buttons were in the end :) $\endgroup$
    – Doodled
    Mar 7, 2016 at 7:43
  • $\begingroup$ Tiny details make a big difference sometimes and it can be very difficult to figure out. And then they'll change it in the next version. lol $\endgroup$
    – dedwarmo
    Mar 8, 2016 at 12:05

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