Extrude contour lines normal on surface

Hey there,
I want to extrude this red contour lines on this violet surface in grasshopper.
I have done it on rhino but it is a very tiring and time-consuming process.

  1. offset each curve one at a time on the surface. using an offsetnormal command.
  2. Then loft both curve separately.

Please download the attached files for reference.

Please help.!!

lofted columns.3dm (1.1 MB)

Hi @Huzefam1,

There are really two ways (I can think of) that you can approach this.

The first one being, to move curve points along the surface normals at the specific locations and redrawing interpolated curves through these points. These curves can then be used with their corresponding initial curve to form a loft. The resulting surface will be doubly-curved.

The second method would be to average the sampled normals of each curve and use that average vector to extrude the curves. You’ll end up with a single curved extrusion, if I’m not mistaken.

offset_normal_on_surface.gh (11.2 KB)


Thank you so much :slight_smile:

1 Like

Two other ways.

  1. Offset the surface and map the curves to the offset, then loft between.

  2. Use Pufferfish Offset Curve From Surface component, then loft between.

Offset Normal To Surface.gh (64.9 KB)


Thanks this seems easy!