#14 bug in g-stl for windows?

release 7.8
closed-rejected
Sean Morrison
5
2006-11-08
2006-11-07
ecbngc
No

"g-stl" provides for specification of a conversion
tolerance "-D", yet when I modify the value over
several orders of magnitude the number of
facets/triangles stays constant.

The geometry is a sphere-cone, and so decreasing
tolerance should result in increasing number of facets.

Discussion

  • ecbngc
    ecbngc
    2006-11-07

    copy of g-stl, test1 containing rv.r, and rv.stl

     
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  • Sean Morrison
    Sean Morrison
    2006-11-07

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    If I'm understanding you correctly, this isn't a bug -- there are four different tessellation tolerances that come into play. Run g-stl without any options to see the list, but they are -a (absolute), -r (relative), -n (normal), and
    -D (distance). They have to all coincide otherwise you'll just run into one of the other tolerance limits. To simply increase the number of polys quickly, the absolute tolerance is usually the most straightforward way to
    increase the count.

     
  • Sean Morrison
    Sean Morrison
    2006-11-07

    • assigned_to: nobody --> brlcad
    • status: open --> pending-rejected
     
  • John Anderson
    John Anderson
    2006-11-08

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    The -D tolerance is a calculational tolerance. Any two
    vertices within this distance
    of each other are considered the same vertex. This tolerance
    does not affect facetization.
    The options that adjust the facetization are -a, -r, and -n.
    The "-a" option specifies an absolute tessellation tolerance
    - the maximum allowed distance (mm) between the real surface
    and the facets
    The "-r" option specifies a relative tessellation tolerance
    - an absolute tolerance is calculated as the relative
    tolerance times the "size" of the object being tessellated
    (for a sphere, the "size" is the radius).
    The "-n" option specifies the maximum surface normal error
    (in radians).
    By default, tessellations are performed using a relative
    tolerance of 0.01. Try using the -r option with values other
    than 0.01.

     
  • ecbngc
    ecbngc
    2006-11-08

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    Thank you both -- issue resolved.

     
  • ecbngc
    ecbngc
    2006-11-08

    • status: pending-rejected --> closed-rejected