Thanks, Alex.  MotionBlur wasn't what I thought it was.  Does anyone know
of a program that does post processing motion blur without having to render
5 or 10 times the number of frames?  I don't want to used the motion_blur
{} megapov thing 'cause it's way too slow.
Tia!

-- 
H.E. Day
<><

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H. E. Day <Pov### [at] aolcom> wrote:
: Does anyone know
: of a program that does post processing motion blur without having to render
: 5 or 10 times the number of frames?

  It's not possible to calculate post-process motion blur.

  Well, ok, you can calculate _something_, but it's extremely limited:

  - Only motion blur of an object moving exactly parallel to the viewing
    plane and facing exactly the camera all the time. No motion blur of
    an object moving also in the depth-axis nor changing position with
    respect to the camera, nor rotating, nor changing shape, nor changing
    other features (like color, brightness)... Just think about a rolling
    pool ball...

  - Post-processing can't use sub-pixel information and thus the result will
    be more coarse (it's the same difference as the antialiasing made by
    povray, which calculates sub-pixel information by sending more rays per
    pixel, compared to just blurring the non-antialiased image afterwards
    with a painting program).

  - If some other object reflects or refracts this moving object, the
    reflection/refraction of the object will not be motion-blurred.
    If the object is behind a transparent object, it can't be blurred
    correctly. Specially if the moving object is partially behind a
    transparent object, the blurring will be horribly wrong.

  - If the moving object is partially transparent, the scene seen through the
    transparent part will be wrongly blurred (shouldn't be blurred at all
    if the scene is static). Also if the object is reflecting, the reflection
    will be wrongly blurred.

:  I don't want to used the motion_blur
: {} megapov thing 'cause it's way too slow.

  The motion blur in megapov is suprisingly fast.
  Ok, if your moving object is very complicated and takes a lot of time
to trace even without motion blur and it takes a lot of image area, then
the motion blur makes it slower, of course. However, it will still be faster
than calculating n frames and averaging them.
  For simple objects which render fast, the motion blur in megapov is just
excellent.
  The syntax of the motion blur of megapov makes it also very easy to
calculate the exact amount of blurring per frame (ie. it simulates the time
the shutter is open). By other methods you would have to calculate the
amount of blurring by hand. This can be pretty hard if the motion of the
object is not constant.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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|   It's not possible to calculate post-process motion blur.

Untrue.  Take a look at the link:
http://www.revisionfx.com/mblur.htm 
And you will see that pp motion blur is indeed possible (if not desirable).
 As for objects only moving according to the camera plane, I guess you've
never used photoshop.  There is a  filter - radial blur - that allows you
to do rotation and zooming blurs, all very fast.  All I'm looking for is a
freeware product to do the same thing in a animation.
Hope that explains what I'm looking for a bit better.

H.E. Day
<><

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On 23 Nov 2000 16:51:51 -0500, "H. E. Day" <Pov### [at] aolcom> wrote:

>And you will see that pp motion blur is indeed possible (if not desirable).
> As for objects only moving according to the camera plane, I guess you've
>never used photoshop.  There is a  filter - radial blur - that allows you
>to do rotation and zooming blurs, all very fast.  All I'm looking for is a
>freeware product to do the same thing in a animation.
>Hope that explains what I'm looking for a bit better.

Maybe The GIMP can help you.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg

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H. E. Day <Pov### [at] aolcom> wrote:
:  As for objects only moving according to the camera plane, I guess you've
: never used photoshop.  There is a  filter - radial blur - that allows you
: to do rotation and zooming blurs, all very fast.

  Since photoshop can't create new information from the 3D-object from a
2D image, the rotation will always be limited to a rotation parallel to
the viewing plane.
  This is seldom the case. Just think about the rolling pool ball. You will
probably not make it roll exactly parallel to the viewing plane.
  The point is that when the object rotates, new features from the "other
side" will become visible while other details in the other end of the
object will rotate behind the object.
  For example, think about the number in the pool ball. At the beginning of
the motion-blur path the number may be just in the other side of the ball
(and thus not visible) and when the ball rotates the number comes to the
visible side.
  No 2D-program can generate this kind of extra information to a 2D image.

  As for the zooming blur, you forget that zooming and moving the object
in the depth-axis are two completely different things.
  When you zoom, you are just scaling the 2D image bigger or smaller. No
new details are calculated.
  However, when you move an object in the depth-axis, the shape of the
object is changed due to perspective. An object very near to the camera has
a different shape than an object far away from the camera. For example, if
you look at the earth from very close distance, you can see only eg. 10% of
its surface. If you look at the earth from far away, you can see a bit less
than 50% of its surface.
  This means that moving an object in the depth-axis can bring more information
or hide some information (or both).
  Again, no 2D-program can do this.

  Another thing is that when an object is moving, it can go partially behind
another object (or come from behind another object). Again, no 2D-program
can simulate this.

  And all what I said in my previous article...

  And as I said, megapov's motion blur is just magnificent. Incredible.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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>   It's not possible to calculate post-process motion blur.
[snip the limited cases where it's possible to simulate it]

	I recently found a page talking about some possible method
which should have been implemented and tested. Unfortunately, neither
algo is discribed in detail, nor source-code is available...

http://techweb.kingston.ac.uk/research/vision/foci/postprod.html

	The whole page is interesting, some funny MPEG-1 animations.
You also can directly jump to the "Motion blur" section.


*** Nicolas Calimet
*** http://pov4grasp.free.fr

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|   And as I said, megapov's motion blur is just magnificent. Incredible.
Warp, warp. My man.

Which do you think I'll be more likely to use, complex objects or simple
ones?

Uh-huh.

It's me, buddy. :)
--
H.E. Day
<><

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In article <01c05674$40cdd440$617889d0@daysix>, "H. E. Day" 
<Pov### [at] aolcom> wrote:

> Which do you think I'll be more likely to use, complex objects or simple
> ones?

Complex ones. Which means it is even more likely that post_process 
"motion blur" won't do what you want.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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"H. E. Day" <Pov### [at] aolcom> wrote in message
news:01c05674$40cdd440$617889d0@daysix...
> |   And as I said, megapov's motion blur is just magnificent.

    Too right, accept for the fact that you can't do something like this :

#declare foo=
pigment { color clock }

motion_blur {
 sphere { 0 1 pigment { foo } }
}

--
Scott Hill.
Software Engineer.
E-Mail        : sco### [at] innocentcom
PGP Key       : http://pgpkeys.mit.edu:11371
Pandora's Box : http://www.pandora-software.com

*Everything in this message/post is purely IMHO and no-one-else's*

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In article <3a2196f5@news.povray.org>, "Scott Hill" 
<sco### [at] innocentcom> wrote:

> "H. E. Day" <Pov### [at] aolcom> wrote in message
> news:01c05674$40cdd440$617889d0@daysix...
> > |   And as I said, megapov's motion blur is just magnificent.

Actually, Warp said that. :-)


> Too right, accept for the fact that you can't do something like this :
> 
> #declare foo=
> pigment { color clock }
> 
> motion_blur {
>  sphere { 0 1 pigment { foo } }
> }

Actually, that is a good thing...motion blur is only applied to what you 
specify it for, which is far better than having it applied to 
everything, whether or not you want it. Maybe if "blur_clock" was used 
instead of "clock" this would be less confusing...a warning or error 
could be generated when it is used outside of a motion blur block.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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