It's affected by how the user has zoomed. Here is a calculation that
gives you what you seem to be asking for:
from visual import *
box(pos=(-5,0,0))
box(pos=(5,0,0))
show = label()
#scene.range = 100 # with this, initial label is 200 (+/-100)
while 1:
rate(50)
d = mag(scene.mouse.camera-scene.center)
w = 2*d*tan(0.5*scene.fov)
show.text = "%.1f" % w
Bruce Sherwood
Joe Heafner wrote:
>> Is there a way, e.g. a function, to return the width of a VPython
>> scene in real life units independent of what's displayed in the scene?
>> For example, if I'm modeling Sun and Earth and I have them on opposite
>> sides of a scene, can I obtain the scene's width (~ 1.5e11 m) with a
>> function call? scene.width gives the width in pixels. I'm trying to
>> take the drudgery out of manually calculating scale factors for
>> displaying arrows.
>>
>> Joe Heafner
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