Originally Posted by
rkmcswain
I'll try to explain using an example:
Let's say the drawing was created on a different machine by a different company. On that machine, they have a font named "simplex.shx", but they have customized the font by adding some characters. Then they created some text with these special characters.
Now they send you the drawing, and you have "simplex.shx", but it is not the exact same file. So when AutoCAD tries to display the special characters added by the others, it can't and reports "undefined shape..." (each character in a font file can be referred to as a shape).
Hope that helps.