In article <385D166D.CE6C6CE8@bentanimation.com>, Colin Doncaster 
<col### [at] bentanimationcom> wrote:

>   I am playing around with MegaPov, currently the motion blur feature.
> It's seems like a pretty decent patch for motion blur, camera motion
> blur can be simulated by moving all the objects over time in the
> opposite direction the camera is moving.  I have two questions - first
> of all, is there a way to jitter the motion blur ray?  Right now if you
> specify 5 samples, you get a stepped look to the blur which, with
> jittering, I think would be removed or at least lessen the artifact.

It is possible, if you use a counter to control the blur manually. It is 
also possible without the counter variable if you take the delta 
value-the "exposure time"-into account, although I haven't taken the 
time to figure that one out yet.

#declare motBlurSamps = 5;
#declare expTime = 1;
global_settings {
   assumed_gamma 1.8
   motion_blur motBlurSamps, expTime
}

#declare rStrm=seed(156153);
#declare CLK=clock;//this is outside any motion_blur block
                   //so it isn't affected by the blur.
                   //Use this variable in place of clock
                   //where blur is controlled manually

//"conventional" motion blur, with the clock variable
motion_blur {
   sphere {< 0, 0, 0>, 0.5
      texture {BallTex}
      translate x*clock
      translate y*1.25
   }
}

//manually controlled motion blur, makes things like jitter
//and directional blur possible
#declare C=0;
motion_blur {
   sphere {< 0, 0, 0>, 0.5
      texture {BallTex}
      translate x*(C/(motBlurSamps-1))*rand(rStrm)
      translate x*CLK
      translate -x*0.5
   }
   #declare C=C+1;
}

I posted some source in povray.text.scene-files which you might find 
useful.


> Second, is it possible to blur deforming geometry?  If in the motion
> blur block I specify and if, and say, if this is the first pass of the
> motion blur object use this mesh, if second step use this mesh and
> repeat it for each sample step, I should, in theory, be able to blur
> deforming geometry - right?

Yes, it is possible. Anything that changes within the motion_blur block 
will be blurred, with the exceptions of light_sources and the camera.



> BTW - any good tutorials available for creating procedural surfaces?

If you mean the isosurface, I am working on one, and there is one online 
here: http://members.aol.com/stbenge/


> Oh yeah - is displacement available?

A form of displacement can be done with the isosurface patch.


> And another thing :) is a 4.0 version
> being developed.  thanks.

POV-Ray 3.5 version is being developed, which will incorporate many of 
the patches that have been created. POV-Ray 4.0 will be a rewrite of 
POV-Ray in C++.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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