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Am 07.10.2016 um 21:18 schrieb omniverse:
> "omniverse" <omn### [at] charter net> wrote:
>> After reading about this at:
>>
>>
http://news.povray.org/povray.documentation.inbuilt/message/%3Cweb.57f3be98a39309ab21263ef70%40news.povray.org%3E/#%3
> Cw
>> eb.57f3be98a39309ab21263ef70%40news.povray.org%3E
>>
>> I had to get another look for myself at what happens when changing viewpoint for
>> +z. Found the x and y rotations appear opposite, yet z remains counterclockwise
>> when seen from these different directions and with the change to x sign.
>>
>> First is the usual view for many POV-Ray scenes with camera at a -z coordinate,
>> looking toward +z. The default 'up' +y and 'right' +x (or <4/3,0,0>).
>
> Second is with negative 'right', or right <-4/3,0,0>, and 'up' still positive y.
The reason why rotation about Z /appears/ to remain the same is that
from the camera's point of view it /appears/ like you've achieved the
change in handedness (which flips all rotations) by flipping the Z axis
(which additionally flips the rotation around the Z axis); so
effectively you've flipped the apparent rotation about the X and Y axes
once, and the rotation about the Z axis twice making it the only
rotation that appears unchanged.
If you chose the opposite camera perspective for the 2nd video, you
could achieve that the Y and Z axes appear to remain the same and the X
axis appears to be flipped; in that case, the rotation about the Y and Z
axes would appear to be flipped, and the rotation about the X axis would
appear to remain unaffected.
Likewise, you should also be able to make it appear as if rotation about
the Y axis remained unaffected but the other two flipped, or to make
rotation about all three axes to appear flipped.
I haven't thought it through entirely yet, but I suspect it is
impossible to flip the handedness while making rotations about an odd
number of axes appear unaffected.
Post a reply to this message
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// cmd:+w320 +h240 +fj +a0.1 +ki0 +kf1 +kfi1 +kff150
#version 3.7;
global_settings
{
assumed_gamma 1
ambient_light 0
}
#local LR=0; // 0 for left-handed, 1 or any number for right
light_source
{
<11,11,-11>, 1
}
camera
{
#if (LR=0)
location <6,8,-10>
right <4/3,0,0>
#else
location <6,8,10>
right <-4/3,0,0>
#end
up <0,1,0>
look_at <0.5,1.75,0>
angle 60
}
#if (LR=0)
plane
{
-z,-7
texture
{
pigment
{
rgb 0
}
finish
{
reflection 1
}
}
no_shadow
//no_image
}
#else
plane
{
z,-7
texture
{
pigment
{
rgb 0
}
finish
{
reflection 1
}
}
no_shadow
}
#end
// room grid
box
{
<-12,-12,-12>*0.99,<12,12,12>*0.99
texture
{
pigment
{
function {abs(x)}
color_map
{
[0.15 rgb <1,0,0>]
[0.15 rgb <1,1,1>]
}
}
finish
{
emission 0.1 diffuse 0.6
}
}
texture
{
pigment
{
function {abs(y)}
color_map
{
[0.15 rgb <0,1,0>]
[0.15 rgbt <1,1,1,1>]
}
}
finish
{
emission 0.1 diffuse 0.6
}
}
texture
{
pigment
{
function {abs(z)}
color_map
{
[0.15 rgb <0,0,1>]
[0.15 rgbt <1,1,1,1>]
}
}
finish
{
emission 0.1 diffuse 0.6
}
}
}
// axis center
sphere
{
0,0.5
texture
{
pigment
{
rgb 0.1
}
finish
{
emission 0.1 diffuse 0.6
specular 0.5 roughness 0.05
}
}
}
#declare Axis=
union
{
cylinder
{
-x*3,x*3,0.25
texture
{
pigment
{
gradient x
color_map
{
[0.5 rgb <0,1,1>]
[0.5 rgb <0.5,0.5,0.5>]
}
}
finish
{
emission 0.1 diffuse 0.6
specular 0.25 roughness 0.1
}
}
}
cone
{
x*3,0.33,x*4,0
texture
{
pigment
{
rgb 0.75
}
finish
{
emission 0.1 diffuse 0.6
specular 0.25 roughness 0.1
}
}
}
}
object
{
Axis
}
object
{
Axis
rotate <0,0,90>
}
object
{
Axis
rotate <0,-90,0>
}
// rotating box
box
{
-1,1
texture
{
pigment
{
checker rgbt <1,1,0,0.5> rgbt <1,0,1,0.5>
}
finish
{
emission 0.1 diffuse 0.6
specular 0.5 roughness 0.01
}
}
scale 2
//translate -z*5
#if (clock<0.333)
rotate <3*clock*360,0,0>
#local Xd=1; #local Yd=0.3; #local Zd=0.3;
#else
#if (clock<0.667)
rotate <0,3*clock*360,0>
#local Xd=0.3; #local Yd=1; #local Zd=0.3;
#else
rotate <0,0,3*clock*360>
#local Xd=0.3; #local Yd=0.3; #local Zd=1;
#end
#end
}
text
{
ttf "arialbd"
"X",0.2,0
no_shadow
texture
{
pigment
{
red 1
}
finish
{
emission 0.1 diffuse Xd
specular 0.5 roughness 0.05
}
}
translate <4.5,-0.25,0>
}
text
{
ttf "arialbd"
"Y",0.2,0
no_shadow
texture
{
pigment
{
green 1
}
finish
{
emission 0.1 diffuse Yd
specular 0.5 roughness 0.05
}
}
translate <-0.25,4.5,0>
}
text
{
ttf "arialbd"
"Z",0.2,0
no_shadow
texture
{
pigment
{
blue 1
}
finish
{
emission 0.1 diffuse Zd
specular 0.5 roughness 0.05
}
}
translate <-0.25,-0.25,4.5>
}
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Attachments:
Download 'p-r_rh_aerobics_mirror.mp4.mpg' (710 KB)
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