I was wondering - is it possible to do motion blurring based on the
actual translate commands?  What I mean is, create a motion blur from
the translate amount, clock delta, and clock?  For example:

sphere {0,1 translate -20*z*clock}

would produce a linear (vector based) motion blur in the z direction,
assuming motion blurring has been turn on.  This would obviously need
some adjustment for spline based scenes. Perhaps a MBlur_Amount or
Blur_Distance?
Anyway, just an idea that would cut down on the render time required for
the use of a motion blur in povray. Can anyone make sense of these
ramblings and perhaps translate (no pun intended) them into reality?


H.E. Day

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On Wed, 24 Nov 1999 20:55:35 -0800, "H.E. Day" <mil### [at] teleportcom>
wrote:

>I was wondering - is it possible to do motion blurring based on the
>actual translate commands?  What I mean is, create a motion blur from
>the translate amount, clock delta, and clock?  For example:
>
>sphere {0,1 translate -20*z*clock}
>
>would produce a linear (vector based) motion blur in the z direction,
>assuming motion blurring has been turn on.  This would obviously need
>some adjustment for spline based scenes. Perhaps a MBlur_Amount or
>Blur_Distance?
>Anyway, just an idea that would cut down on the render time required for
>the use of a motion blur in povray. Can anyone make sense of these
>ramblings and perhaps translate (no pun intended) them into reality?
>
>H.E. Day

I have successfully used averaged frames to make motion blur. A quick
(and dirty) way to increase rendering speed is to only render those
objects that move, using the +ua option, and then superimpose the
averaged result over the previously rendered rest of the scene. This
has the disadvantage of breaking shadows and reflection, but this can
be fixed, too, though it will make more time (render- and otherwise).


Peter Popov
pet### [at] usanet
ICQ: 15002700

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Peter Popov wrote:

> I have successfully used averaged frames to make motion blur. A quick
> (and dirty) way to increase rendering speed is to only render those
> objects that move, using the +ua option, and then superimpose the
> averaged result over the previously rendered rest of the scene. This
> has the disadvantage of breaking shadows and reflection, but this can
> be fixed, too, though it will make more time (render- and otherwise).
>

Hmmm. Ya got my brain working more.

I imagine that one could hook in some image analysis to help. Just render
two frames spaced normally. Then do a diff and locate the rectangle areas in
the images that changed from one to the next. Then re-render sub-frames with
only these sections specified. This should catch reflections, etc. also.

Hmmmm... depending on implementation details, this might actually give good
results. I imagine that it would be best for scenes with the camera
stationary, and fewer things moving. Parse-time would also need to be
monitored.

Quite an interesting problem...

--
"My new computer's got the clocks, it rocks
But it was obsolete before I opened the box" - W.A.Y.

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On Thu, 25 Nov 1999 12:36:16 -0800, "Jon A. Cruz"
<jon### [at] geocitiescom> wrote:

>Hmmm. Ya got my brain working more.
>
>I imagine that one could hook in some image analysis to help. Just render
>two frames spaced normally. Then do a diff and locate the rectangle areas in
>the images that changed from one to the next. Then re-render sub-frames with
>only these sections specified. This should catch reflections, etc. also.

Unfortunately, it doesn't work.  If the "before" and "after" positions
of the object don't intersect in screen-space, you might neglect to
rerender the space in between for each subframe.  The object also
might not just move within the rectangle bounded by its beginning and
ending positions.

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As have I. (take a look at my IRTC entry, the one with the pod racers.)

Peter Popov wrote:

> On Wed, 24 Nov 1999 20:55:35 -0800, "H.E. Day" <mil### [at] teleportcom>
> wrote:
>
> >I was wondering - is it possible to do motion blurring based on the
> >actual translate commands?  What I mean is, create a motion blur from
> >the translate amount, clock delta, and clock?  For example:
> >
> >sphere {0,1 translate -20*z*clock}
> >
> >would produce a linear (vector based) motion blur in the z direction,
> >assuming motion blurring has been turn on.  This would obviously need
> >some adjustment for spline based scenes. Perhaps a MBlur_Amount or
> >Blur_Distance?
> >Anyway, just an idea that would cut down on the render time required for
> >the use of a motion blur in povray. Can anyone make sense of these
> >ramblings and perhaps translate (no pun intended) them into reality?
> >
> >H.E. Day
>
> I have successfully used averaged frames to make motion blur. A quick
> (and dirty) way to increase rendering speed is to only render those
> objects that move, using the +ua option, and then superimpose the
> averaged result over the previously rendered rest of the scene. This
> has the disadvantage of breaking shadows and reflection, but this can
> be fixed, too, though it will make more time (render- and otherwise).
>
> Peter Popov
> pet### [at] usanet
> ICQ: 15002700

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On Thu, 25 Nov 1999 18:30:11 -0800, "H.E. Day" <mil### [at] teleportcom>
wrote:

>As have I. (take a look at my IRTC entry, the one with the pod racers.)

As have you, but did you render everything or just the moving objects
to generate the motion blur? If so, what was the speed increase over
the conventional method?


Peter Popov
pet### [at] usanet
ICQ: 15002700

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Everything was moving, thus +UA had no effect.  I doubt this would have any
speed increase, but I'll check.

H.E. Day


Peter Popov wrote:

> On Thu, 25 Nov 1999 18:30:11 -0800, "H.E. Day" <mil### [at] teleportcom>
> wrote:
>
> >As have I. (take a look at my IRTC entry, the one with the pod racers.)
>
> As have you, but did you render everything or just the moving objects
> to generate the motion blur? If so, what was the speed increase over
> the conventional method?
>
> Peter Popov
> pet### [at] usanet
> ICQ: 15002700

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On Fri, 26 Nov 1999 18:57:55 -0800, "H.E. Day" <mil### [at] teleportcom>
wrote:

>Everything was moving, thus +UA had no effect.  I doubt this would have any
>speed increase, but I'll check.
>
>H.E. Day

Object masking with +ua is of no help if the camera is moving (which
it almost always does in anims). Only simple object showoff anims will
benefit speedwise from this approach.


Peter Popov
pet### [at] usanet
ICQ: 15002700

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