Hi,
your problem caused by your drawing UCS !!!!
The user coordinate system (UCS) establishes the location and orientation of a movable Cartesian coordinate system. The UCS is an essential tool for many precision operations. The UCS defines :
- The horizontal and vertical directions used for features like Ortho mode, polar tracking, and object snap tracking
- The alignment and angle of the grid, hatch patterns, text, and dimension objects
- The origin and orientation for coordinate entry and absolute reference angles
SO .. if you type UCS command >>W ( world ) THEN type PLAN command and double enter. NOW go to your drawing to discover that you have a bad drawing ... isn't it ? you have a polylines elevation with Z values .
Command: UCS
Current ucs name: *NO NAME*
Specify origin of UCS or [Face/NAmed/OBject/Previous/View/World/X/Y/Z/ZAxis] <World>: w
Command: PLAN
Enter an option [Current ucs/Ucs/World] <Current>:
i suggest to fix your issue is make your UCS ( World ) as mentioned above then type FLATTEN Express Tools command to kill Z values for all of your selected items ( to change the Z values of all lines, arcs, and polylines to 0. ) >> Click << . BUT you still have unclosed truss . so now you have to redraw your lines again.
Imad Habash
