#856 Weird behavior when rotating a triangle

[Melançon Guy]

I was playing with node shapes, and got interested in triangles (to obtain psychedelic effects by repeating patterns and alignments).

Imagine I create a triangle of width 2 and height 1 so its base is larger than its height with the triangle pointing upwards.

When assigning it a viewRotation of let's say 90 or -90 I expected the triangle to point sideways.

But I get strange effects and I simply can't figure out what transform is applied to the triangle.

I thought I would report my experience to see whether it's because I do not know how to position the viewRotation parameter or because the transform follows some exotic, hard to guess rule ...

[brenoust]

Hi Guy,

A quick answer, the unit is the issue. You make a 360dg rotation with 2*pi
(pi is 180dg, etc.) the rotation is also counter clockwise is the screen
space.

--
Benjamin

On 6 May 2017 at 03:39, Melançon Guy melancon@users.sf.net wrote:

---

• [bugs:#856] https://sourceforge.net/p/auber/bugs/856/ Weird behavior
  when rotating a triangle*

Status: open
Group: 3.5.x
Created: Fri May 05, 2017 06:39 PM UTC by Melançon Guy
Last Updated: Fri May 05, 2017 06:39 PM UTC
Owner: nobody

I was playing with node shapes, and got interested in triangles (to obtain
psychedelic effects by repeating patterns and alignments).

Imagine I create a triangle of width 2 and height 1 so its base is larger
than its height with the triangle pointing upwards.

When assigning it a viewRotation of let's say 90 or -90 I expected the
triangle to point sideways.

But I get strange effects and I simply can't figure out what transform is
applied to the triangle.

I thought I would report my experience to see whether it's because I do
not know how to position the viewRotation parameter or because the
transform follows some exotic, hard to guess rule ...

---

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[Patrick Mary]

Thanks to Benjamin who explained everything.
"viewRotation" values indicate counter clockwise angular measure expressed in radians.