acad lt 2019 3d poly lines to poly lines

[Anonymous]

i have 2 issues

1.  I have a closed 3d poly line but when I go to hatch it, it says a closed boundary cant be determined.  Yet it says in properties that it is closed.

2.  How do I change from 3d polyline to a normal polyline?  My other hatches are done simply on a normal polyline.

[Kent1Cooper]

You may be able to use Pline3Dto2D.lsp, available >here<.  Read various Messages on that thread for some other approaches, considerations, etc.

[pendean]

Because you are posting in the wrong forum, you will get solutions that you cannot use in LT2019 version of AutoCAD.

You need to recreate it as a 2DPline, try BOUNDARY command (if it is truly flat of course) or EXPLODE it then join all the lines back together with PEDIT command.

The LT forum is over here fore your future needs https://forums.autodesk.com/t5/autocad-lt/ct-p/2000

[steven-g]

You have 2 options, providing, of course, the 3Dpoly is actually closed.

1) select the 3Dpoly and in properties highlight the vertex box which gives you a roll-over arrow, then go through each vertex looking for any Z values and change each vertex to Z=0 even if it says 0 you still need to highlight the Z value until it shows it is in editing mode (blue highlighted) and physically type '0' 

2) explode the 3Dpoly and select all the resulting lines, then again use the properties palette and change the values for 'Start Z' and 'End Z' to Z=0 (make sure the value is blue and physically type 0), then use "JOIN" command to make it back into a polyline.

NOTE: you have to change every 'vertex/endpoint' physically to zero because it might show as 0 but actually have a number small enough to be beyond the precision settings.

Or as an alternative redraw the object as a simple polyline by picking the vertex points of the 3D polyline, but when you go to pick the first point use an .xy point filter and tell LT that the Z value =0 when prompted for "need a Z value", any further points you click will all be Z=0 as a polyline can only ever be drawn on a plane.