How to convert splines to polylines in AutoCAD

To convert a single spline, use the SPLINEDIT command:

1. At the command line in AutoCAD, type SPLINEDIT.
2. Select the spline if it was not already selected.
3. Type P for convert to Polyline.
4. Specify the precision <0-99>.

Before SPLINEDIT:
 

After SPLINEDIT:
 

To convert multiple splines at the same time, use the PEDIT command:

1. At the command line in AutoCAD, type PEDIT.
2. Type M for Multiple.
3. Select the splines.
   • Note: The PEDIT command does not allow splines to be selected beforehand.
4. Type Y to Convert Lines, Arcs and Splines to polylines.
5. Specify the precision <0-99>.
6. Press the Esc key to exit the command.

Alternatively:

1. Enter the SAVEAS command.
2. Resave the drawing in AutoCAD R12/LT2 DXF (*.dxf) format.

Note: This older file format does not support splines and will automatically change them to 3D polylines. Keep in mind though that other data structures in the drawing may also be affected. To avoid this, select the splines to convert and use the WBLOCK command instead.