Converting Polyline ARC segment to multiple LINE segments

[earthsquare]

Hi.
Is there an option to convert, polyline ARC segment to multiple LINE segmnets.
The decurve option, converts the arc into single line.
Regards

[pendean]

Nothing built in to do that if I understood your need correctly (my guess is you need a curved tile edge?).

Can you use POLYGON command to create a circle with line segments at a matching radius, then EXPLODE and replace the ARC?

[maxim_k]

Hi Sreejith,

As @pendean mentioned, there is no build-in functionality for converting polyline arc segments to series of straight lines, but I believe you can use AutoLISP routine to accomplish this.

I have found one (see attached), but it works only with old-style "heavy" polylines, so before using it you need to convert "light" polyline to "heavy" with CONVERTPOLY (undocumented) command:

https://www.cadforum.cz/cadforum_en/command.asp?cmd=convertpoly

Then APPLOAD attached LSP file and use PLXL command, which has "Deflection angle" option which allows you to control number of line segments by changing "Deflection angle" - the greater is this value, the more segments will be created.

After using the routine you can convert "heavy" polyline back to "light" with CONVERTPOLY command

Here you can read more about "heavy" and "light" (Lightweight) polylines.

[earthsquare]

Hi,
I was trying to use wipeout command. It unfortunately recognises only polylines with line segments and not arc segments. The workaround is to manually draw multiple polyline, line segments around the curve. The problem is that it is not perfect  as the original block.
Regards
Sreejith.S

[earthsquare]

Hi Maxim,
Hope you are doing great. 
Thanks for the tips. let me try it and get back to you.
People like you, make AutoCAD a better space to work with.
🙂
Regards

[maxim_k · Accepted solution]

Here is another way, without using AutoLISP.
The limitation of this method is that you can use it with closed polylines.

- Draw polyline with arc and line segments, ensure it is closed
- Use SUPERHATCH command with Wipeout option and create wipeout by picking point inside closed polyline
- move resulting wipeout to empty space in order to be able to work with it freely
- use EXPLODE command to explode wipeout to lines
- use JOIN command to join lines to new polyline.

You can control number of lines which approximate arc segments with SUPERHATCHTOLERANCE system variable (default value is 0.01)

[earthsquare]

Hi.
I work on AutoCADLT for Mac 2020. I think APPLOAD and PLXL doesn't work.
regards

[maxim_k]

OK. then try:
https://forums.autodesk.com/t5/autocad-for-mac-forum/converting-polyline-arc-segment-to-multiple-lin...

[earthsquare]

Thank you.
It worked.

[c.haynes-BM]

Hi does anyone know how to do the opposite of this?

I wish to convert Polylines made up of multiple LINE segments to Polylines with ARC segments with the least amount of nodes as possible

[maxim_k]

Hi Chris,

Try PEDIT command with Fit (or Spline) option:
http://help.autodesk.com/view/ACDMAC/2018/ENU/?guid=GUID-648BDC21-E835-478F-A318-9D201479998D

[JaysonE]

Easiest way I have found is to:

1. create a dummy surface around your polyline. (you can do this with break lines)

2. create an outer boundary to your polyline.

3. set the mid-ordinate distance to a very low number. (like 0.1')

This will create a polyline with segments without arcs.

[tomislav_vargek]

Hello.

So, I edited original PLXL.lsp so now it takes LWpolylines also, if anyone needs it.

[Anonymous]

I really appreciate it, but I thinks there's a bug in the code. 😞

[pendean]

@Anonymous How doe it fail for you? Please elaborate.

[gramosC4MGW]

Convert the 2D Polyline to a 3D Polyline.  Then convert it back to a 2D Polyline.  It should create small line segments along the arcs so you can use that polyline for wipeouts.

[julie.walker2]

very neat solution, thanks! (pendean's polygon solution) didn't even need to explode, just used the polygon for the wipeout.
Command: Polygon
choose number of sides
select center point
select edge of circle
Inscribe IN because I wanted wipeout to be within the circle
boom, polyline.
Command: wipeout, polyline, select polyline, no for erase polyline
Move to back, and I made my circle and the wipeout a group because it's in a block and I get unpredictable results when I import the block, with the wipeout trying to move to the front, but I don't know if that's the best way to accomplish that. If anyone has an solution for that I'm all ears

[drafting605]

You're awesome! This made my life so much easier! 

[ceinig]

Converting 2D Poly to 3D poly was the solution I was looking for.

[r_baccioni]

Convert poliline using wmfout, then import the wmf back using wmfin. Explode the block and join.