Offsetsrf Failure On Complex Polysurface

This Result can be caused by various issues with the source file. Adjust the geometry in the file and try the import process again'). Only after significantly splitting or deleting control points down to a small portion can I get this object to import. I've sucessfully imported similar, but more complex surfaces from the same Rhino file into Revit. It only operates on solid, manifold polysurfaces. Selected polysurface faces are removed, the remaining faces are offset inward, and the inner and outer parts are joined. OffsetSrf - works on polysurfaces and solids. Options for round or sharp corners.

Toolbar Menu

Solid

Surface

Offset Surface

The OffsetSrf command copies a surface or polysurface so that locations on the copied surface are the same specified distance from the original surface.

Steps

  1. Select a surface or polysurface.
  2. Infinite Plane: Type IP for InfinitePlane options.

  3. Type the offset distance, and press Enter.
Offsetsrf failure on complex polysurface examples
Command-line options

Distance

Sets the offset distance.

Corner

Specifies how offset corner continuity handled. These options only apply if the offset direction is to the 'outside' as shown in the image.

Sharp

Curves offset to the outside of a corner will be extended to meet at sharp corners with position (G0) continuity.

Round

Curves offset to the outside of a corner will be filled with arc segments with tangent (G1) continuity.

FlipAll

Flips the offset direction of all selected surfaces. Arrows indicate the positive offset direction.

Note: This option is not available when any of the selected objects is a polysurface.

Tolerance

Sets the tolerance for the offset surface. Type 0 to use the default tolerance.

BothSides

Draws the offset on both sides of the original.

DeleteInput

Yes

Deletes the original geometry.

No

Retains the original geometry.

Note

  • Positive values offset in the direction of the arrows. Negative values offset the other way.
  • When a plane, torus, sphere, open cylinder, or open cone surface is offset, the resulting surface is exact. Free-form surfaces are offset to within the value of the Tolerance option.
  • When offsetting a polysurface with free-form sub-surfaces, the results might have some surfaces missing.
  • The output object adopts the rendering material from the input object.

See Also

OffsetMesh

Copies a mesh by moving the vertices a specified distance with different direction modes.

Offsetsrf failure on complex polysurface symptoms
OffsetSubD

Makes a copy of a SubD by moving its vertices towards the normal direction with the specified distance.

ToolbarMenu

Solid Tools
Solids Sidebar

Symptoms

The Shell command creates a hollowed out shell from a solid.

Shell only operates on simple, solid, manifold polysurfaces. These surfaces are removed and the remainder is offset inward, using the outer parts of the removed surfaces to join the inner and outer parts.

Steps

Offsetsrf Failure On Complex Polysurface Work

  1. Select faces to remove from closed polysurface.
    Leave at least one face unselected.
  2. Press Enter when done
    This step specifies which surfaces will be removed to make the shelled object.

The top surface of the cylinder was selected for removal.
Command-line options

Thickness

Specifies the thickness for the shell.

Troubleshoot shelling

Shell and OffsetSrf for polysurfaces are works in progress. There are several known problem areas:

  • Singular surfaces can cause problems, especially when the offset of the surface must be extended at the singularity. The extensions are done in OffsetSrf (Corner=Sharp) and shelling, which always uses sharp corners. These extensions happen when the offsets of adjacent surfaces come apart. Also, cone-like singularities cause problems in all cases.
  • Complex vertices (ones with more than three edges) can be problematic, especially in shelling and sharp corner offsets and where some, but not all, of the surfaces at the vertex offset apart.
  • OffsetSrf on polysurfaces with naked edges, where the naked edges make concave boundaries will not work correctly.
  • If faces adjacent to the removed faces offset in such a way that the removed face must be extended to fill in the gap, it will fail.
  • Any surface whose offset self-intersects will cause a problem.

Offsetsrf Failure On Complex Polysurface Symptoms

See also

Rhinoceros 7 © 2010-2020 Robert McNeel & Associates. 11-Dec-2020