I'm working on some animations and want to create a single image with 
the moving objects in their various positions, so I can easily debug my 
movement parameters without generating lots of images.

So, I've had the idea of using the 'transmit' value to make earlier 
instances appear as "echoes" so that it's obvious which are the older 
and which are newer. Attached is a scene which gives a very simple 
example of what I mean by the "echoes".

But my question is this -- if I have a complex object composed of the 
union of dozens (or hundreds!) of pieces, with a range of distinct 
textures, can this be done?   I was hoping something like:

    object { MyComplexMacro(.....) translate a1 transmit 0.0 }
    object { MyComplexMacro(.....) translate a2 transmit 0.6 }
    object { MyComplexMacro(.....) translate a3 transmit 0.2 }

Which of course is nowhere near correct, but is it possible to apply a 
'transmit' value (or another feature) to a complex object to make an 
"echo" like in this manner?

Thanks
------------------------
#include "colors.inc"

camera {
     location <15.0, 50.0, -10.0>
     look_at <15.0, 0.0, -10.00>
     direction z*1.3 up y right x*1.33
}

light_source { <-50.00, 60.00, -10.00> color White }
light_source { < 50.00, 60.00, -50.00> color White }

#macro mySphere(num)
   #local xmit = sqrt(num);
   sphere{ <30,0,-10>, 2 pigment {color rgb<1,0,1> transmit xmit } 
rotate num*y*75 translate <0,0,10> }
#end
 

#declare num = 8; 

#declare nn = 0; #while (nn<num)
         mySphere(nn/num)
         #declare nn = nn+1;
#end

plane { -y, 2 texture { pigment {color rgb<0.0,0.7,0.5> }}}

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news:40182367$1@news.povray.org...
> Which of course is nowhere near correct, but is it possible to apply a
> 'transmit' value (or another feature) to a complex object to make an
> "echo" like in this manner?

Well, you can turn every texture into a macro and parameterize the transmit
value. It can be done, but could take some time to rig properly. Also,
having many complex transparent objects on top of each other could be
extremely slow and the results confusing and not that helpful.
I have little animation experience, but it seems to me that the "single
image" trick isn't a good way to debug an animation unless it's very simple.
It will help debug the positions, but not the movement itself. Unfortunately
I don't see much alternatives to using dummy textures and dummy objects (for
speed) and then rendering the entire animation.

G.


-- 
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Gilles Tran wrote:
> Also, having many complex transparent objects on top of
> each other could be extremely slow and the results confusing and not
> that helpful.

I agree. What is needed to make the echoes idea work is not images with
transparent objects, but transparent images of solid objects. To get
multiple echoes, multiple images must be rendered. however, if you want
to render the whole animation at once with "echoes", then you can do it
with almost no extra render time. First render the whole animation like
you would normally do. Then create a separate scene file which has just
a plane with a texture in it. The texture should then be an average of a
few of the frames from your animation (This can be done automatically).

Once you create your echoes this way, they are much less confusing, and
may be quite helpful debugging your animation. Not only can you debug
positions, it will also give you a sense of the speed, and
acceleration/deceleration etc. Of course it's still only a supplement to
viewing the animation in motion, that is, just another debugging tool,
not THE debugging tool...

Rune
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rune|vision:  http://runevision.com **updated Dec 30**
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Gilles Tran wrote:


> news:40182367$1@news.povray.org...
> 
>>Which of course is nowhere near correct, but is it possible to apply a
>>'transmit' value (or another feature) to a complex object to make an
>>"echo" like in this manner?
> 
> Well, you can turn every texture into a macro and parameterize the transmit
> value. It can be done, but could take some time to rig properly. Also,
> having many complex transparent objects on top of each other could be
> extremely slow and the results confusing and not that helpful.

Thanks Gilles, Rune.

FYI, this is for enhancements to a set of animation macros, and this 
question was for a subset that would wrap around the animation portion 
of the script and could be switched on/off by commenting a line or two.

The intent of the subset of macros is to allow tweaking the movements 
and *QUICKLY* generate a single image to see the motion.  And then 
repeat as needed.

Although I like the visual effect of the "echoes" for its own merit, I 
wanted this as a additional information when the user tries to verify 
proximity of objects, the shape of a path, or things of that nature.

The subset of macros works now -- but without any fading.  I'd hoped 
that adding fade would be less difficult.  Oh well.

Marvin

PS: The macro package (called "TikTok") is a work that I started mid '03 
and showed to Gilles in Aug'03.  I'm just now getting back to polishing 
it up, with examples & some reasonable docs.

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