I’ve been using Rhino for a few years on a low level, but I have never had this happen before. I extruded two curves straight up at a 90-degree angle in the Front view. Then I tried to make a boolean union but it keeps showing an error. When I zoom into the top right corner it shows a line of the extrusion shoots our past the edge of the extrusion surface wall. Please see the picture.
Is this why the boolean union won’t work? Why is my Rhino 6 doing this?