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-   -   【转帖】autocad rendering of degenerate arcs (http://www.dimcax.com/hust/showthread.php?t=15187)

yang686526 2009-05-04 04:30 PM

【转帖】autocad rendering of degenerate arcs
 
autocad rendering of degenerate arcs
autocad rendering of degenerate arcs
if i have a dxf file with two arcs.
both have a start angle of 0 degrees
the first has an end angle of 360.0 degrees
the second an angle of 359.9999999999999999999999999999 degrees
autocad will represent the first as a degenerate arc by a point
the second is degenerate (visually anyway) as a complete circle.
what tolerance is used to decide on these two representations ?
gerry
default tolerance used in autocad is 1.e-10.
but full circle can't be represented with ac(od)dbarc entity. after any transform operation (say move) arc with angles 0-360 will be converted to arc having both start and end angles zeroed. full circle will become a point after it.
any transform in autocad makes 360 degrees start or end angle be equal to zero.
sergey slezkin


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