> Hm, I'm not quite sure, if this alone solves the issue of having motion blur
> with POV 3.7. Should this wonderful superman not having decreasing transparency
> during the flight? If you only average pictures of the flight, you will probably
> get more blur than expected, since POV doesn't know the sequence of the
> pictures. May be, proper weights in the average map will help. But you are still
> limited to 256 entries. An other approach is to have copies of the blurred
> object with decreasing transparency in the scene. But to find the correct
> positions and transparencies is the hard job. Christian Froeschlin gave an
> example with his entry "glocken" at the IRTC april 2006, which shows the idea
> but the difficulties likewise (rendered at a higher resolution then the original
> entry).
>
> Best regards,
> Michael
>
>

For the comicks like decreased transparency.
In this sample scene, all frames have the same weight, but it can be 
changed:
    #for(V, 1, n_frames)
     [V // the weight goes from 1 to n_frames.
      #declare image_name = concat(image_name_, str(V, 
-(log(n_frames)/log(10) +
1), 0))
      image_map{image_type_() image_name}
      translate -(x+y)/2
     ]
    #end

By replacing the [1 by [V, the first image have a weight of 1, the 
second a weight of 2,...
You can also use V/n_frames if you want to keep the weight parameter no 
larger than 1.
You can increase the last image further in a few ways:
Add some number to the last image's weight.
Use pow(V,2) or pow(V/n_frames,2) for the weight. You can use a power of 
3, 4 or some intermediate value if you want.
This assume that each frame is created in the direction of the movement 
and that you want the last frame to dominate.

The limit of 256 entries is not a problem unless you have a very long 
motion blur trail. If you use decreasing transparency, it's even less of 
a problem, even with rather long trails.



Alain

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