#35 Piece of edge omitted

Raytrace (49)

Look at http://ronja.twibright.com/3d/ and search for
string "holder.php"
The third view (holder_3s.png) has in lower right
corner a bolt with nut. The circular edge is displayed
only in half.

rtedge was called with default settings which imply
that difference between distance hit makes an edge
(default on). There is a difference in distance hit,
however only half of the edge is displayed.


  • John Anderson

    John Anderson - 2006-04-15

    Logged In: YES

    One way edges are detected is by a difference in hit
    distance between adjacent rays. The difference must be
    greater than some threshold in order to identify an edge.
    The threshold is calculated based on the distance between
    adjacent rays, and that distance is determined by the
    resolution of the image (512x512 default). The threshold is
    calculated to insure that a planar surface at 87 degrees to
    the view direction will not result in adjacent rays showing
    a false edge (simple trigonometry). The difference in hit
    distance at the missing edge in this example is below the
    threshold at 512x512. The missing edge will appear in a
    4096x4096 image, which can then be scaled back to 512x512.
    Another way to get the edge to appear is to make the bolt
    and nut seperate regions with different ident numbers.

  • Erik Greenwald

    Erik Greenwald - 2007-11-15

    Logged In: YES
    Originator: NO

    "max_dist" has been to rtedge's configuration variables. It should provide a functional, though non-optimal solution.

  • Erik Greenwald

    Erik Greenwald - 2007-11-15
    • assigned_to: nobody --> erikgreenwald
    • status: open --> closed-fixed

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