Newbie - Editing a solid

TrapezoidPrism.3dm (51.7 KB)
I have been using Extrude Planar Curve To Point to create polygon pyramids. Triangle, square, hexagon, etc. But I now want effectively extrude a trapezoid to a line. I started by extruding the trapezoid twice to two points and then union joining these, resulting in the attached file. This results in an unwanted divot cut out of the top.

  1. How do I edit out this divot? I thought I could just delete two points…
  2. How might I have achieved the desired result by effectively doing an “Extrude Planar Curve to Line


Welcome to the Rhino forum.

To edit the shape you created: Explode the shape, Untrim the sides, Trim the sides, Join TrapezoidPrism DC.3dm (45.2 KB) But there are better ways to create the desired shape starting with a curve and line.

Extrude Planar Curve to Line does not exist in Rhino. However the loft command can be used, though a closed curve will need to be split into at least two curves. TrapezoidPrism DC Loft.3dm (63.0 KB)

Rhino fundamentally works with lines, curves and surfaces, and has a large number of commands for creating and editing geometry. A solid in Rhino is a closed surface.

Don’t make the mistake of assuming since you know how to use some other modeling software that Rhino works the same that you have used. It almost certainly doesn’t. Take time to go through the available tutorials, starting with the User’s Guide which is really an introductory tutorial. To learn more go through the Level 1 and Level 2 training manuals. Many good videos are also available.


Thank you, David!