Re: [Visualpython-users] how can I rotate a frame ?

[Stef M. <s.m...@ru...>]

hello Bruce,
thanks for your fast respones.

Bruce Sherwood wrote:
> I think you need to give more information. I don't know what I'm 
> supposed to do to see the "weird behavior", nor do I know in what way 
> it is "weird".
Sorry for the confusion, by "weird" I mean not as I expect,
so probably I don't use the right algorithm to fulfill my expectation.

Below is piece of code, showing my problem.
I've two boxes, a normal box, blue
and the same box, but green, in a frame.
Now I want to rotate the box in the frame, and thus the whole frame,
exactly the same as the free box.
(I've taken the axis of the boxes in such a way, that represent physical 
properties, so I rather not want to change that)
In the beginning, when the frame is positioned at the origin,
the rotation behavior of free-box and frame are the same.
But when free-box and frame are shifted, this not anymore the case.
So the problem must be in the line that rotates the frame:
test_frame.rotate ( angle = -pi/2, axis = Y_AXIS,
  origin = test_frame.pos + box_frame.pos )
apparently it's not enough to add the frame position and the relative 
position of the box in the frame.

cheers,
Stef




# for reference, display origin and floor
org = visual.sphere (
  pos=(0,0,0), radius = 0.4 )
l = 10.
floor = visual.box (
  pos=(l/2,-1,l/2), axis=(1,0,0),
  color=(1,0,0),
  length=l, width=l, height=2 )

# create a normal box
box_free = visual.box ( color=(0,0,1),
  pos=(2,3,3),
  length = 4,
  width  = 2,
  height = 1 )

# create the same box in a frame
test_frame = frame ()
box_frame = visual.box ( frame=test_frame, color=(0,1,0),
  pos=(2,1,3),
  length = 4,
  width  = 2,
  height = 1 )

# rotate free_box and test_frame, works as expected
Y_AXIS = ( 0, 1, 0 )
box_free  .rotate ( angle = pi/2, axis = Y_AXIS )
test_frame.rotate ( angle = pi/2, axis = Y_AXIS,
  origin = test_frame.pos + box_frame.pos )

# now move the box and the frame in the z-direction
box_free.z   += 2
test_frame.z += 2

# rotate box and frame back
box_free  .rotate ( angle = -pi/2, axis = Y_AXIS )
test_frame.rotate ( angle = -pi/2, axis = Y_AXIS,
  origin = test_frame.pos + box_frame.pos )




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