How can I select/find all objects in a circle?

Hallo,
I have drawing (ACAD2002) with a circle and any objects in the circle.
With my vba-program I search all circles in the drawing. This part from
the program work fine.
Now I must select / find all objects in the circle - objects complete and
incomplete in the circle. How can I do it with vba?

Hartmut

 

If you don't mind cheating ...

You may be able to temporarily cross hatch the circle and then use the
"IntersectWith" method to find anything that intersects with the cross
hatch.

Gary

 

2) Approximate a circle with a series of short line segments and use

This function will create a polyline with a given number of facets for a
circle.
http://groups.google.com/groups?q=facetcircle+group:autodesk.autocad.customi
zation.vba

You could try sending this polyline to the SelectByPolygon method. I've
seen some people having problems with this method, but I don't know if it's
still problematic.
http://groups.google.com/groups?q=SelectByPolygon+group:autodesk.autocad.cus
tomization.vba

James

 

This would be my approach:
  1. Using the bounding box coordinates of the circle, do a "Select acSelectionSetCrossing" against the "square" that contains the circle.
  2. Iterate through the selection set doing an IntersectWith against the circle.
  2a. Any objects that get a "hit" are included.
  2b. Any objects that don't get a hit are either completely inside or completely outside the circle. For each object grab any point associated with it (eg vertex, centroid) and draw a ray through the centroid of the original circle. Then do an IntersectWith to see how many times the ray hits the circle. If it's an odd number of times then the object is within the circle and should be included in your result. (For completeness you should check that the arbitrary point on the object you choose is not in fact itself the centroid of the original circle, otherwise the ray approach will fail. Of course if it is the centroid then this object too is inside the circle.)
  
Regards
  
Wayne Ivory
IT Analyst Programmer
Wespine Industries Pty Ltd