AcadSchemes

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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.

Default
2007 Lines
2007 Natural
2007 Polylines
2007 Solids
CAM Imperial
CAM Metric
R12 Lines & Arcs
R12 Natural

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.

Release 12
Release 14
Release 2000
Release 2004
Release 2007
Entities only

AutoCAD Release 12 DXF only.

Export surfaces as
Solids

Simple solids export to AutoCAD as 3DSolids (SAT).

Curves

The wireframe is exported as curves. Use settings on the Curves tab to specify how these and other curves are exported.

Meshes

Surfaces are exported as polyface meshes.

Use the Create Mesh from NURBS object dialog box to adjust the mesh settings.

Export meshes as
Meshes

Export meshes without modification.

3DFaces

Each face in a polygon mesh is exported as a separate 3DFace.

Some programs that read DXF files may read 3DFaces, but may not properly read polyface meshes.

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.

Do not project

Objects are not projected.

CPlane

Project to the active construction plane.

View

Project to the active view plane.

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

Rhino Objects

AutoCAD Objects

Lines

Lines

Polylines

3DPolylines

Splines

Arcs

Lines

Arcs

Polylines

3DPolylines

Polylines w/bulge arcs

Splines

Polylines

Lines

Polylines

Polylines

3DPolylines

Splines

Curves

Lines

Polylines

Polylines

3DPolylines

Splines

Polycurves

Lines

Polylines

Polylines

3DPolylines

Polylines w/bulge arcs

Splines

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
Maximum angle

When exporting curves as polylines, Rhino must approximate each curve with a polyline. The Maximum angle setting, combined with the Chord height and Segment length settings, determine how the polylines are created.

The Maximum angle option sets the maximum angle between adjacent polyline segments. The larger this number, the farther away the polyline segment midpoints are from the original curve.

Chord height

The distance from the polyline segment midpoint to the curve will be less or equal to this number. Smaller numbers make the polyline fit the curve better, but they also increase the number of polyline segments.

Segment length

The maximum length of a polyline segment. This setting uses current model units and ensures that all polyline segments are shorter than this setting.

The physical size of the model should be taken into consideration when using this setting exporting a boat that is 100,000 units long with a maximum segment length of 0.01 will result in millions of polyline segments and a huge DWG/DXF file.

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.
New

Creates a new scheme.

See: Naming conventions in Rhino

Save

Saves the currently selected scheme.

SaveAs

Saves the currently selected scheme with a new name.

Delete

Deletes the currently selected scheme.

Rename

Renames the currently selected scheme.

Export

Exports the settings to a scheme file.

Import

Imports the settings from a scheme file.

Close

Closes the AutoCAD Export Schemes dialog box.

See also

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

Export DWG/DXF with an external scheme file