Troubleshooting Naked Edges
Join Dave Schultze for an in-depth discussion in this video Prototyping part 5: Troubleshooting naked edges, part of Rhino: Tips, Tricks & Techniques. Lynda.com is now LinkedIn Learning! To access Lynda.com courses again, please join LinkedIn Learning. All the same Lynda.com.
Note: The result of a command is always a mesh regardless of the input object type. What makes Boolean operations fail? Boolean operations can fail for a number of reasons: ● Normals may not point the way you expect. ● tend to stack up at the intersection of the two objects.
● Objects may have overlapping surface areas. Surface Normals The Boolean operations use the surface normal to determine which parts to keep and which to throw away. When you attempt a and you get a instead, or vice versa, this is because the objects have normals that are the opposite of what you expect. This tends to happen often if one or more objects are not fully closed. If an object is not closed, Rhino has no way to determine which side is outside and which is inside. Use the command to see which way the normals point on these objects and use the Flip option as needed to make sure the normal direction is what you consider to be the outside of the object. Fully closed objects will always have normals pointing outward.
Coincident Control Points Coincident control points occur when the control points at the edge of a surface are at an identical location. This occurs in Rhino naturally at the tip of a cone or the pole of a sphere or a three-sided plane. You can also move control points to the same location. This point is also called a singularity. When a singularity point occurs at the intersection of two objects you want to Boolean, the operation can fail. Overlapping Surface Area Overlapping surface areas occur when two surfaces share the same area. In this example, the two boxes are just touching along one side.
The objects will, but, and will not work. Nonmanifold edges In addition to overlapping surfaces, non-manifold edges can also cause failures. Edges of polysurfaces or meshes that have more than two faces joined to a single edge are non-manifold. The illustration shows polysurfaces with non-manifold edges highlighted with the command. What to do If your objects won't Boolean, you can use other techniques to get the results you want.
Troubleshooting Edge Browser
In this example, the apex of the cone is exactly at the corner of the box. This is one of the situations that can cause the Boolean operations to fail. Instead of using Boolean operations in this case, use the command to separate polysurfaces into single surfaces if necessary. Use the command to create curves that represent the intersection of the two surfaces. To create the parts, use these curves to and/or and then them back together.