Expert: Bill DeShawn - 8/3/2011

Question
I'm working with Acad 2012 and I have to regularly draw wipeouts for various drawing blocks to mask the underlaying lines. These drawing blocks have all sorts of forms and geometry, and it can be a time consuming process to manually trace the outline of these blocks in order to create a wipeout. Is there an easy way to create a more or less tight fitting wipeout?

If the geometry of the block is simple, I can first create a boundary, which transforms into a wipeout quite easily (provided there are no arc segments in the boundary). However, the drawing blocks that I wish to make a wipeout for, have complicated geometry, and when I try to make a boundary Acad just crashes. Please advise.

Answer
You could use the bpoly command to create a boundary, explode the polyline and replace any arcs in it with a series of straight lines.  Other than that, there is no other way.  Only if either the wipeout command could automatically make the change or bpoly could give you the option to make the boundary with arcs or series of short lines.  Or also if the wipeouts could be made with arcs.  I have to do the same, by the way.  I am quite familiar with your dilemma.  Do the work.  You won't regret it.  It's the best way to mask your block.

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