 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
http://cgg.ms.mff.cuni.cz/~semancik/localcopy/geocities/projekty.html
I don't remeber having seen this mentioned before. Non-linear ray tracing
with POV-Ray, see the end of the page.
Ingo
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
ingo <ing### [at] tag povrayorg> wrote:
> I don't remeber having seen this mentioned before. Non-linear ray tracing
> with POV-Ray, see the end of the page.
Unless you can apply the non-linear transformation on a per-object
basis (so that its shadow and its reflection/refraction on other objects
etc are also transformed correctly), the effect is rather useless
(except for making some abstract art).
Also, I would like to know whether the rays used to render those images
were really curved or if they were just straight rays transformed on
a non-linear basis (similar to what eg. the normal{} block in a camera
statement would do).
--
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}// - Warp -
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Warp wrote:
>
> Also, I would like to know whether the rays used to render those images
> were really curved or if they were just straight rays transformed on
> a non-linear basis (similar to what eg. the normal{} block in a camera
> statement would do).
I suppose it's either tracing piecewise linear rays or always using a
numerical root solver (like POV-Ray does for isosurfaces). In any case
it would be quite slow.
Christoph
--
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 23 Sep. 2004 _____./\/^>_*_<^\/\.______
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Christoph Hormann <chr### [at] gmxde> wrote:
> I suppose it's either tracing piecewise linear rays or always using a
> numerical root solver (like POV-Ray does for isosurfaces). In any case
> it would be quite slow.
I think all those example images could be rendered by simply
applying proper (linear) transformations to the rays (this is not
possible with the official povray because you can't apply a completely
free transformation to each camera ray, but it shouldn't be too
difficult to write such patch).
The problem with this approach is that it simply distorts the entire
image (in the same way as normal{} in the camera block does) and does
not really result in a transformation of an object (it would not be,
however, the same thing as a 2D transformation of the image because eg
the shading of the objects would change according to the direction of
the rays, and thus you would get a much more convincing "distortion" of
the scene than just a 2D distortion of the final image).
Even if you transformed the rays freely on a per-object basis (it would
also be quite easy to write such patch) you could get an object which
looks non-linearly transformed but only when directly viewed from the
camera (its problem would be that its shadow and its reflection/refraction
on other objects would not work correctly).
In order to understand what I mean by my last paragraph above, think
what happens when you transform a ray to the local space of an object:
The ray is multiplied with the inverse of the transformation matrix
of the object in question. Nothing would stop us from performing other
type of transformations to this ray at the same time: For example, the
ray could be translated in the y axis by an amount equivalent to x^2
(taking the x coordinate of the ray at a certain z position, for example).
This would make the object to seemingly "bend" in a parabolic way
downwards.
The effect can, in fact, be quite convincing when directly viewed
from the camera. However, I believe that for example the shadows of
the object would not be correct (they would not correspond to an object
bent that way from the camera point of view). Also if there was a
mirror where we could see the object from another direction, I think
it would also show an object which looks completely different.
--
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}// - Warp -
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Wasn't it ingo who wrote:
>http://cgg.ms.mff.cuni.cz/~semancik/localcopy/geocities/projekty.html
>
>I don't remeber having seen this mentioned before. Non-linear ray tracing
>with POV-Ray, see the end of the page.
I don't seem to have anything on my machine that can read that .ps file.
Does it use his own modified version of POV, or does it use the
user_defined camera facility that's in MegaPOV?
--
Mike Williams
Gentleman of Leisure
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
in news:dqq### [at] econymdemoncouk Mike Williams wrote:
> I don't seem to have anything on my machine that can read that .ps file.
http://www.cs.wisc.edu/~ghost/gsview/
> Does it use his own modified version of POV, or does it use the
> user_defined camera facility that's in MegaPOV?
It's done using a modified version of POV-Ray .
Ingo
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
in news:41dfc3b8@news.povray.org Warp wrote:
> Unless you can apply the non-linear transformation on a per-object
> basis (so that its shadow and its reflection/refraction on other
> objects etc are also transformed correctly), the effect is rather
> useless (except for making some abstract art).
Usefull or not, the interesthing thing is that it is done and that it is
done using POV-Ray. In the paper he also discusses non-linear
transformation on per object basis.
> Also, I would like to know whether the rays used to render those
> images were really curved or [...]
The paper on the site describes how it's done.
So far, I havn't found the source, if it's onlne at all, although the
paper suggests it.
Ingo
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 8 Jan 2005 04:43:40 -0500, ingo <ing### [at] tagpovrayorg> wrote:
> Non-linear ray tracing
> with POV-Ray
http://news.povray.org/povray.binaries.animations/attachment/%3C3a70570b%40news.povray.org%3E/DEFORM.MPG
http://news.povray.org/povray.binaries.animations/attachment/%3C3a6f152e%40news.povray.org%3E/ONMIRROR.MPG
http://news.povray.org/povray.binaries.images/attachment/%3C3a782898%40news.povray.org%3E/chevy.jpg
It was all the time box{}/sphere{}/mesh{} internally and rays were "curved"
instead (segmented in fact but with parametrised accuracy).
ABX
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
