Am 29.11.2013 13:09, schrieb Le_Forgeron:

>> BTW, I'm still looking for a smarter name for that keyword. Anyone have
>> any suggestions?
>>
>
> only a few suggestion & hints via questions:
>   1. what is the syntax ? Is it something like
>
> ....
>    foobar { object MyObject repetition 20 movement ...
>
> ? Or something totally different (like photon adding blocks everywhere ) ?

The syntax of the feature per se is as simple as

     OBJECT {
       ...
       blink [FLOAT,] FLOAT
     }

giving a time interval, in fractions of exposure time, during which the 
object is supposed to be visible in the scene (defaulting to "blink 0.0, 
1.0", i.e. the entire exposure time).

To use it for motion blur, you would use it as in the following example:

     #local DeltaT = 0.1;
     #for( T, 0.0, 1.0, DeltaT )
       sphere {
         <T,0,0>, 1
         blink T, T+DeltaT
       }
     #end


>   2. what is the intended effect ?

The intended effect of the feature per se is to make a given object 
appear to be present in the scene only during a part of the exposure time.

Thus, besides motion blur, it could also be used to simulate double 
exposure. E.g. you might add a "gost" to the image, an object that is 
transparent with respect to the remainder of the scene but opaque when 
it comes to occluding itself.


>   3. how is it achieved ? and would that be the only forever way to
> achieve it ?

Each ray shot is tagged with a point in time (currently at random), and 
each ray-object intersection test begins with a test whether that point 
in time is within the given object's "blink" time interval; if it isn't, 
the ray is considered to miss regardless of geometry.


> The effect on first post of thread make me think of the after-effect
> that was used in the "Flash" serie (post 90's)
> so I could suggest:
>
>   * flash_effect (not my favortie at all)

Don't want to name it after a particular instance of use.

>   * drag / pull / dragging / moving

Nope, as the basic effect is unrelated to movement.

>   * shutter_drag

Have to investigate what that would be supposed to mean.

>   * blurry / blur

Nope, as the basic effect is unrelated to blur.

>   * moving_supersampled

Again nope (unrelated to movement), but a variation might fit.

>   * motion_trails
>   * motion_blurred
>   * trails
>   * motion

Nope (unrelated to either movement or blur).

>   * shutter_control
>   * shutter
>   * slow_shutter

Might be possible to do something with this.

>   * slow

Nope, as we aren't slowing anything there.

>   * extended_exposure

Might also be a direction to go in.


> And of course, use a synonym website to find correlated name/verb until
> you have the perfect match.
>
> The term in photography is shutter drag, or dragging the shutter, but
> it's just a bit too long for my taste.

Well, that would be the term for the motion blur effect I guess, but 
this feature is rather unrelated to motion blur, except that you can use 
it to achieve this effect. For standard cases (such as steady motion 
along a straight path or steady rotation) I'll add some dedicated syntax 
that will require only one instance of the object.

> (and there is the option to add a
> flash point (or many) for a more solid capture of the subject along its
> course).

That sounds more like what the effect actually does. (Still doesn't 
exactly cut it; I guess that would be more fitting in the contect of an 
actual motion blur feature, to specify that a particular point in time 
should be exaggerated.)


Maybe I'll go for "ghost" in the end.

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