Pickray

[ahjkuipers]

Hello to all,

There's something I don't understand (no, many things) and that's about pickray.
Suppose I have a model existing of a single edge. Then I create a ray from the eye through one of the two endpoints of the on screen projection and try to find the intersection of that ray with the edge. Why is the ray (a line) missing the edge? I'm totally confused because I presumed that the result had to be the startposition (or endposition, depending of the screencoordinates) of the edge.

An example

def exp_a
  mod = Sketchup.active_model
  view = mod.active_view
  ents = mod.entities
  ents.clear!
  edges = ents.add_edges([0, 0, 0] , [100, 100, 100]) 
  edge = edges[0]
  pt = view.screen_coords(edge.start.position)
  ray = view.pickray(pt.x, pt.y)
  Geom.intersect_line_line(edge.line, ray)
end

The result is nil.

Can anybody tell me what is wrong with my assumption that in this case the result should be [0, 0, 0]? What is wrong with my understanding of pickray?

[thomthom]

Maybe due to precision issue?
Not sure, but you don't have to convert between screenpoints like that:

  mod = Sketchup.active_model
  view = mod.active_view
  ents = mod.entities
  ents.clear!
  edges = ents.add_edges([0, 0, 0] , [100, 100, 100]) 
  edge = edges[0]
  pt1 = edge.start.position
  pt2 = view.camera.eye
  Geom.intersect_line_line(edge.line, [pt1, pt2])