I have a 3d curve lying on the unit sphere and I would like to cut the sphere into two "regions" delimited by this 3d curve. My goal is to put the region inside of the curve one color and the other side another color.

However, I'm unable to cut the mesh properly. I tried the knife tool but it's very tedious and I'm looking for something I can just use the curve I have.

enter image description here

  • $\begingroup$ Unit sphere? You mean mesh sphere? $\endgroup$ Commented Jan 2 at 3:37
  • $\begingroup$ Yes, in my case it was the icosphere that I subdivided enough times to approximate a unit sphere $\endgroup$ Commented Jan 2 at 3:55
  • $\begingroup$ Can you fill the surface "inside" the curve, make it "tick", then use a boolean modifier to remove this "interior" part from the sphere ? By the way, could you share your Blender file using blend-exchange.com ? $\endgroup$ Commented Jan 2 at 5:38
  • $\begingroup$ What's the context? Why do you need this? Is this just a modelling step, or do you need it to be possible to animate/update or something like that? What do you need this for? $\endgroup$ Commented Jan 2 at 7:31
  • 1
    $\begingroup$ @MartynasŽiemys I am using Blender for rendering figures for an academic paper. So it only needs to look good for the render, no need to animate. $\endgroup$ Commented Jan 2 at 14:58

1 Answer 1


Simple way to do this would be to select the curve, select the sphere, enter edit mode and use Knife Project. You can find it in Mesh menu or using search( F3 ) It's view dependent so the view should be somewhat straight to the surface of the sphere through the curve.

enter image description here


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