PLINETYPE system variable
Function Description:
The PLINETYPE system variable is used to control whether to use optimized 2D polylines.
Type : Integer 
Saved in : Registry 
Initial value : 2 
Range : 0,1,2 
System Variable Value:
0 : do not convert polylines when opening an old drawing; PLINE creates polylines in old format.
1 : do not convert polylines when opening an old drawing; PLINE creates optimized polylines. 
2 : do not convert polylines when opening an old drawing; PLINE creates optimized polylines.
The PLINETYPE system variable also controls the polyline types created by the following commands: BOUNDARY, DONUT, PEDIT, POLYGON, and SKETCH.