Sketchup: Constructing Triangle with Ruby

Ruby
1

Hello,

i’m constructing triangles with ruby and try to plot them within
Sketchup. In most cases, this works. But sometimes, an error occurs:
“Points are not planar”, which is quite strange for a triangle…

model = Sketchup.active_model
entities = model.active_entities
k = 0
for i in 1..3 do
    x = arr[k]
    y = arr[k+1]
    z = arr[k+2]

    pts << Geom::Point3d.new([x,y,z])

    k += 3
end

pts << pts.first()

begin
face = entities.add_face(pts)
rescue
puts $!.message
puts pts
end

arr is an array with the triangle coordinates (the coordinates come from
an external data source, but thats not the problem)

An example output for an error is

Points are not planar
(0,08255m, 0,003858m, 0,11049m)
(0,083007m, 0,004218m, 0,11049m)
(0,082855m, 0,004111m, 0,11049m)
(0,08255m, 0,003858m, 0,11049m)

The last and the first point are the same, but thats correct (a face is
constructed by a closed line).

o you have any ideas where I can find the error?

2

On Jan 28, 2008 9:11 AM, Eps I. [email protected] wrote:

    x = arr[k]
begin

–
Posted via http://www.ruby-forum.com/.

My wild guess:
The first and last points may differ as they are built out of floating
point numbers.
Try integers to represent the points, at least , the first and the last.

Prasad

3

G.Durga P. wrote:

My wild guess:
The first and last points may differ as they are built out of floating
point numbers.
Try integers to represent the points, at least , the first and the last.

Prasad

Well… I don’t think so. The first and last point are exakly the same,
bit by bit, as you can see here:

pts << pts.first()  # adding last point

But thanks anyway…

4

Eps I. wrote:

G.Durga P. wrote:

My wild guess:
The first and last points may differ as they are built out of floating
point numbers.
Try integers to represent the points, at least , the first and the last.

Prasad

Well… I don’t think so. The first and last point are exakly the same,
bit by bit, as you can see here:

pts << pts.first()  # adding last point

But thanks anyway…

If you want a 3 sided shape, pass 3 points (AKA vertices) to
entities.add_face, not 4.

Todd

(Do I get the old post resurrection award today?)