【转帖】entity coordinates different than in autocad
 

entity coordinates different than in autocad
entity coordinates different than in autocad
hello,
the attached drawing contains two lines. one in the xy plane (z=0.0). the other lies parallel to the xy plane. autocad displays this line at z=-8.3095e+99. the odreadex example states that the line is at z= -8.3095e+269.
could someone explain what is happening?
regards
derek.
attached files
actually the drawing contains values having e+269 range. this is "bad" value for coordinates, for example overflow will happen if an attempt is made to calculate vector length or cross product or dot product etc.
autocad fixes the value in accessor or in displaying routine.
example:
save your sample file to dxf. edit line's z changing e+99 to e+199. load the file into autocad. you'll see z value e+19. autocad simply trancated decimal exponent and used first 2 digits from it.
from objectarx help:
acdbextents();
default constructor. this is typically used to initialize an acdbextents object prior to calling getgeomextents(). it sets the minpoint to a very big value (10 to the 20th power) and the maxpoint to a very small value (minus 10 to the 20th power). note that at this stage the object is in an invalid state, since its minpoint is bigger than its maxpoint.
as a result various problems may happen if coordinates are greater than 1.e+20.
sergey slezkin