Hi!

The following scene doesn't look very nice, because the spheres are 
distorted:

camera
 {
 location z * -3
 up y * 0.5
 right x * 4
 }
light_source { z * -10, rgb 1 }
#declare I = -5;
#while(I <= 5)
 sphere { x * I, 0.3 pigment { color rgb 1 } }
 #declare I = I + 1;
#end

(Render with "+W800 +H100"!)

I'd like to have a "semiorthographic" camera, i.e. one that is horizontally 
orthographic but vertically perspective. This is similar to cylindrical 
projection, type 4 ("horizontal cylinder, viewpoint moves along the 
cylinder's axis") except that is shouldn't be projected onto a cylinder but 
onto a plane.

Does anyone have an idea how to achieve this?

Thank you in advance,
Felix Wiemann

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Felix Wiemann <Fel### [at] gmxnet> wrote:
> I'd like to have a "semiorthographic" camera, i.e. one that is horizontally 
> orthographic but vertically perspective.

  Try the ultra_wide_angle or panoramic cameras to see if they do what
you want. (I think you need to specify an angle in them for them to
work correctly.)

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

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Warp wrote:

> Felix Wiemann <Fel### [at] gmxnet> wrote:
> 
>> I'd like to have a "semiorthographic" camera, i.e. one that is
>> horizontally orthographic but vertically perspective.
> 
>   Try the ultra_wide_angle or panoramic cameras to see if they do what
> you want. (I think you need to specify an angle in them for them to
> work correctly.)

That curves objects with straight edges (e.g. boxes), so it isn't really 
suitable.

-- 
light_source{0#macro L(K,H,W)sphere{H.5}sphere{K.5}sphere{W.5}cylinder{
H,K.5}cylinder{H,W.5}#end 3}union{L(0v*-2<2,-2>)L(y*-3z-v*5z*3-y)L(-y*3
0u*3)L(y*-3v*-5-z,z*-3-y)rotate-v*clock pigment{rgb.5}translate<0,2,9>}
// +KFF200 +KF720 +W120 +H90 -F -A -GA -P

Post a reply to this message

> I'd like to have a "semiorthographic" camera, i.e. one that is horizontally 
> orthographic but vertically perspective. This is similar to cylindrical 
> projection, type 4 ("horizontal cylinder, viewpoint moves along the 
> cylinder's axis") except that is shouldn't be projected onto a cylinder but 
> onto a plane.

Somebody, I think it was ABX, wrote a patch for user-defined cameras.


-- 
merge{#local i=-11;#while(i<11)#local
i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
pigment{rgbt 1}interior{media{emission x}}hollow}//  Mark Weyer

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Mark Weyer wrote:

> Felix Wiemann wrote:
> 
>> I'd like to have a "semiorthographic" camera, i.e. one that is
>> horizontally orthographic but vertically perspective. This is similar to
>> cylindrical projection, type 4 ("horizontal cylinder, viewpoint moves
>> along the cylinder's axis") except that is shouldn't be projected onto a
>> cylinder but onto a plane.
> 
> Somebody, I think it was ABX, wrote a patch for user-defined cameras.

Sorry, I can't find it. Do you have an idea what words to search for or 
where to search it?

-- 
light_source{0#macro L(K,H,W)sphere{H.5}sphere{K.5}sphere{W.5}cylinder{
H,K.5}cylinder{H,W.5}#end 3}union{L(0v*-2<2,-2>)L(y*-3z-v*5z*3-y)L(-y*3
0u*3)L(y*-3v*-5-z,z*-3-y)rotate-v*clock pigment{rgb.5}translate<0,2,9>}
// +KFF200 +KF720 +W120 +H90 -F -A -GA -P

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> Sorry, I can't find it. Do you have an idea what words to search for or 
> where to search it?

See thread
   user_defined camera sample
by ABX from Feb 18 2003 in povray.binary.images


-- 
merge{#local i=-11;#while(i<11)#local
i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
pigment{rgbt 1}interior{media{emission x}}hollow}//  Mark Weyer

Post a reply to this message

> I'd like to have a "semiorthographic" camera, i.e. one that is horizontally 
> orthographic but vertically perspective. This is similar to cylindrical 
> projection, type 4 ("horizontal cylinder, viewpoint moves along the 
> cylinder's axis") except that is shouldn't be projected onto a cylinder but 
> onto a plane.
> 
> Does anyone have an idea how to achieve this?

Another idea, without patches:

Start with a cylindrical type 4 camera.
Surround it with a cylinder of small radius (but not too small, rays
from the camera should be able to reach the cylinder).
Make the cylinder transparent, but give it an ior.
Then adjust the gradient such that the rays go off in the direction
you want them to.

This is not an exact solution, only an approximating one. The camera
rays _after_ refraction do not start exactly at the cylinder's axis.
But if the radius is small enough, the difference is also. Maybe you
can remedy exactness with a second cylinder.


-- 
merge{#local i=-11;#while(i<11)#local
i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
pigment{rgbt 1}interior{media{emission x}}hollow}//  Mark Weyer

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Felix Wiemann wrote:
>I'd like to have a "semiorthographic" camera, i.e. one that is horizontally
>orthographic but vertically perspective.

I think this is what you get "in the real world" using a line scan camera
moving horizontally with the scan line positioned vertically.

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