Z Value Problems

[markvass]

For some time now I've been having problems with Autocad not finding intersections between entities where there should be them.  Some kind person on this discussion group advised there may be a very small Z value and to set the Units value to the highest setting.  I did this and sure enough there is was, a very small Z value of -0.00000008.

The problem I'm having now is that Autocad seems to insist on drawing entities at Z= -0.00000008.  To give an example; I have 4 separate lines creating a rectangle with all entities start points and end points drawn at Z=0.00000000.  I want to connect these lines to create 1 entity (i.e. a closed polyline).  I use the Boundary command as its quicker than fannying about using the Edit Polyline commmand.  But when I create the closed boundary Autocad draws it at Z= -0.00000008.  The Elevation value is set at 0.00000000.  I've never had this problem on previous versions, only from 2008 onwards.

Does anyone have any ideas as this is so frustrating?  By the way, I'm using Autocad LT 2010

Many thanks

[markvass]

Actually, a quick update, it just seems to be doing it with polylines

[pendean]

You could be snapping to objects with a Z elevation while drafting in the file: AFAIK there is no PLINE-ONLY or ANYTHING-ONLY Z elevation settings, so the trigger exists in your file and you must be constantly tapping it.

[markvass]

Thanks for your advice.  On the one hand I accept that the problem could be file related, on the other hand, you are missing the point; I'm not Object Snapping onto anything.  The Boundary command doesn't require an Object Snap but merely creates a Polyline or Region to the boundaries that it finds.  Also I can draw a Polyline completely independent of any other objects (i.e. no object snaps) and again it draws it at Z= -0.00000008, even with the Elevation command set at 0.00000000.  I find the whole thing very strange.

[pendean]

Post a DWG file with the problem: we all have the same exact LT, the problem can either be repeated by us in your file or not and the 'fix' may be more obvious that is remote banter to date.