Expert: Bill DeShawn - 8/31/2009

Question
Hello Bill,


I have a question. You may try try to duplicate this at your end. Draw a circle and make it a block(with base-point at center of circle). Now array the circle to its a 3x3 matrix. draw a rect around it such the a;; circles are inside the rect. make one complete block consisting of rect and the circles. Do a dataextraction and all the correct cordinates for the rectangle and circles show up. Now rotate this big block 90 degrees any direction and try running the data ex command again. I dont get any coordinates for this rotated block. All values for extraction are 0,0 for all X's anf Y's.

Can you please explain why and how to get the correct coordinates even when rotated?


Answer
Himanshu
This is a normal and documented reaction in the notes of the Autodesk Knowlege Base.  On this page:
http://docs.autodesk.com/ACD/2010/ENU/AutoCAD%202010%20User%20Documentation/inde...
you will find the following text:


For a nested block reference, the X,Y, Z coordinate values, scale factors, extrusion direction, and rotation angle reflect the actual location, size, orientation, and rotation of the nested block in the world coordinate system.

In some complex cases, nested block references cannot be correctly represented with only two scale factors and a rotation angle, for example, if a nested block reference is rotated in 3D. When this happens, the scale factors and rotation angle in the extracted file record are set to zero.

What they are saying here, Himanshu is that the block has to be rotated in 3D to get these false results, and that the coordinates for X and Y will be shown as 0,0.  One thing you might want to check it that in the WORLD UCS, is your block showning the Z coordinate at 0,0 or is it something else?

Let me know how it goes.

Bill DeShawn
http://my.sterling.net/~bdeshawn