AcadSchemes

The AcadSchemes command creates AutoCAD export schemes, which determine how various Rhino objects are exported to AutoCAD .dwg and .dxf files.

These options can be saved as schemes for later use. Several schemes that have been determined to give good results are available on the Export Scheme list. You may have to experiment with the options to get the best result from your downstream application.

AutoCAD Export Schemes

Export

Select the export scheme to edit.

General Options

AutoCAD version

When exporting curves to R12 DWG/DXF, curves are approximated with polylines. When exporting to R13/R14/2000+ DWG/DXF, you can export either polyline or spline entities.

Entities only

AutoCAD Release 12 DXF only.

Export surfaces as

Export meshes as

Project to plane

Project objects to the active construction plane or the active view plane. Objects will appear on the world xy plane in the DWG/DXF file. Projecting does not automatically include silhouette lines.

For silhouette lines, see the Silhouette and Make2D commands.

Export full layer paths (Parent$Child)

Export layer names only (Child)

Color by RGB

Exports colors as red, green, blue (RGB) values.

Color by AutoCAD index

Converts RGB colors to ACI (AutoCAD Color Index) colors. White and black in Rhino are both exported as ACI 7.

ACI 7 is a special color in AutoCAD. It displays as black when the viewport background is light, and as white when the viewport background is dark. Rhino does not have such feature.

AutoCAD Color Index is a 255-color palette. Conversion between RGB and ACI only works for the 255 colors. All the rest colors can only be approximations.

Preserve arc normals

Keeps arc normals in their current orientation.

Flip arc normals to +Z

Flips arc normals to be mostly in the + direction of the closest world xyz coordinate.

Whether or not the arc normal is exactly parallel to an x,y or z axis, we want to find the axis to which it is closest to parallel and, if necessary, reverse the arc normal so that it is more parallel to that axis.

Use LWPolylines when possible

Exports 2-D polylines as LWPolylines (lightweight polylines). 3-D polylines are always exported as Polyline entities.

Curves options

AutoCAD Objects

Polylines

All curves are approximated with polylines before exporting. You can adjust the way polylines are created in the Curve tessellation parameters.

3D Polylines

Each point on the polyline can have a different z value.

Polylines w/bulge arcs

If polycurves with arc segments are saved as Polylines and Simplify lines and arcs is checked, they are saved as bulge segments in the polyline. Otherwise, they are tessellated to small straight polyline segments.

Splines

• Exporting Rhino curves as AutoCAD splines is not an option when the AutoCAD version is Release 12.
• All curves are exported as AutoCAD spline entities.
• Rhino curves will be exploded upon export. Rhino polylines will export as multiple separate AutoCAD linear splines. Other Rhino compound curves will translate as separate splines.
• If you have mostly Rhino polylines, you will probably want to export curves as polylines. If you have mostly non-compound curves and want to have real curvature in AutoCAD, export curves as splines.

Curve tessellation parameters

Explode polycurves

Splits polycurves into separate splines at polycurve segment start/end points.

Split curves at kinks

Splits curves into separate splines at kinks.

Simplify lines & arcs

• Circles, arcs, ellipses, and lines export as AutoCAD circle, arc, ellipse, and line entities.
• Rhino compares each curve with an exact arc, circle, line, and ellipse and determines if it can be exported as a simple entity. If the curve is within the simplify tolerance of one of the simple entities, it is exported as a simple entity.
• 2-D curves are simplified. This means if the curve is just one line, arc, or circle, it is exported as an AutoCAD line, arc, or circle. If there are arcs in the curve with discontinuous curvature at the ends, it is exported as a bulge arc in a polyline.
• 3-D curves are never simplified.
• If polycurves with arc or line segments are saved as splines, Rhino will save arcs and lines. Otherwise, separate splines are saved.

Simplify tolerance

• Rhino must evaluate each curve to determine if it is a simple entity. If a curve is within simplify tolerance of an arc, line, circle, or ellipse, it will be exported as such.
• If the simplify tolerance is too large, some curves may export as simple entities when they should not be.
• If the simplify tolerance is too small, some curves may export as simple entities when they should be.
• The default simplify tolerance should work well for most cases.

See also

AutoCAD (.dwg; .dxf; .dwf) Import/Export

Export DWG/DXF with an external scheme file