You can convert geometry of spline to a polyline or an arc in AutoCAD with “Polyline Edit” or PEDIT command. This feature does not convert Polyline to spline or arc rather it gives them all the properties like anchor points and geometry keeping object type as Polyline.
In the Load/Unload Applications dialog box, select the PLINE-3D-2D.LSP file from the support directory where you installed it, click the Load button, and then click Close. After you load the program, AutoCAD prompts you to type PL32 to start. After you enter PL32, AutoCAD prompts you to select 3D polylines, shown highlighted in figure 1. Convert 3D Polyline to 2D Polyline There are various polyline types in AutoCAD®, the most common of which is usually the LWPolyline (lightweight polyline). It can be confusing because the LWPolyline and the old Polyline entity used way back in the early days of AutoCAD® are both shown as a “Polyline” in the Properties window. AutoCAD 2D to 3D Step 1. Use the CIRCLE command to create the following circles. They all have the same center. Use the upper quadrant of the biggest circle to create the following 2 circles. Use the Polar Array command and the two small circles to construct the following set of objects. Instructions provided describe how to create AutoCAD 3D Polyline entities from 3D ArcGIS features using the extended functionality of the Export to CAD geoprocessing tool. Procedure By default, Export to CAD creates planer 2D lightweight polylines where the elevation of the polyline is set to the elevation of the first vertex of the input feature.
Collection of AutoLisp for 3D Polyline Entities - Lisp Help Under 3D Polyline, you can create 3D line by selecting elevation texts in different combination. Also, you can remove the z value of all the vertex of a polyline (Convert 3d polyline into 2D polyline). Applying the 'LCADFLATTEN' command to a 3D polyline will replace a 3D polyline with a 2D polyline. The X and Y geometry will be preserved and the resulting 2D polyline will be placed at a user-specified elevation.
In this article, I will show you how to do it using this sample geometry which is made with a polyline.
Making Polyline look like spline:
Double click on a Polyline to start Polyline edit command or type PEDIT on command line press enter and select Polyline to start Polyline edit command.
2 – PEDIT command line options
Now from command line select spline and press enter. This will make your Polyline look like a spline curve in such a way that vertices of original Polyline curve (shown with the green cross in image 3) will act as control vertices for the spline. The final geometry will look like image 3 shown below.
3 – Polyline spline curve with control vertices indicated by green cross
Although using this method you can change the geometry of a Polyline to a spline but it will still remain a 2D Polyline. When you hover the cursor over this “spline” or check the property then AutoCAD will show it as a 2D Polyline.
You can also convert Polyline to true spline by using Polyline edit command, visit linked article to learn more.
Making Polyline look like Arc:
Double click on Polyline or use PEDIT to start Polyline edit then select Fit from options appearing on the command line.
The Fit option will convert your Polyline into series of tangentially connected arcs. Control points will be added to the geometry at the position where initially vertices of original polyline were present.
You can modify this new geometry using those control points or grips. In this case, also the Polyline will geometrically change to series of connected arcs but it will still remain a 2D Polyline.
Make 3d Polyline 2d
Your final geometry will look like the one shown below.
Do you have any questions related to this tip? Let us know in the comments below.