Hi,

This is my first post but I have used POVRay since the DKB (is that right ?)
days for all sorts.

I've come across this problem before but for the life of me I can't remember
if there is a cure.

The Problem: I'm doing a spinning object towards camera animation of about
2000 frames. The object is quite small to start with. The object is
reasonably complex and therefore all the small polygons flicker due to
there size (we are talking probably only a pixel at this stage). The
animation is fine once it starts to fill the frame.

Any ideas on how to get around this one ?

I've fiddled with the render qualities but with no luck - I did improve it
by turning of reflections but I WANT reflections.

I'm using POVRay 3.6 (I'm sure it'd be the same on all versions though) and
I've been converting the rendered TGA files into a
uncompressed AVI - so compression artefects aren't the problem.

Cheers,

Steve.

Post a reply to this message

sacredblack wrote:

> Hi,
> 
> This is my first post but I have used POVRay since the DKB (is that right
> ?) days for all sorts.
> 
> I've come across this problem before but for the life of me I can't
> remember if there is a cure.
> 
> The Problem: I'm doing a spinning object towards camera animation of about
> 2000 frames. The object is quite small to start with. The object is
> reasonably complex and therefore all the small polygons flicker due to
> there size (we are talking probably only a pixel at this stage). The
> animation is fine once it starts to fill the frame.
> 
> Any ideas on how to get around this one ?
> 
> I've fiddled with the render qualities but with no luck - I did improve it
> by turning of reflections but I WANT reflections.
> 
> I'm using POVRay 3.6 (I'm sure it'd be the same on all versions though)
> and I've been converting the rendered TGA files into a
> uncompressed AVI - so compression artefects aren't the problem.
> 
> Cheers,
> 
> Steve.

Hi Steve, 

A trick that I personally have used before is to average frames.
Either use a linear average so every frame contribute the same amount to the
resulting frame, or use a sin-based average.

Linear:

(Frame 1 + Frame 2 + Frame 3) / 3 = new frame

Sin based:

(sin(45) *Frame 1 + sin(90) * Frame 2 + sin(45)*Frame 3) / 2.41 = new frame

-- 
Ger

Post a reply to this message

Ger <No.### [at] ThankYou> wrote:
> Hi Steve,
>
> A trick that I personally have used before is to average frames.
> Either use a linear average so every frame contribute the same amount to the
> resulting frame, or use a sin-based average.
>
> Linear:
>
> (Frame 1 + Frame 2 + Frame 3) / 3 = new frame
>
> Sin based:
>
> (sin(45) *Frame 1 + sin(90) * Frame 2 + sin(45)*Frame 3) / 2.41 = new frame
>
> --
> Ger

Interesting. Though this looks something like averaging the actual image
generated ?? Possibly to fix flicker caused by fast moving objects. Not
sure.

The problem I have (which isn't really clear on my first post) is a problem
with POVRay rendering detail at only 1 pixel size which changes every frame
making detailed areas that are small (due to location from camera) appear to
flicker (there's probably a better word to describe this problem these
days).

Though I will give your suggestion a go.

Steve.

Post a reply to this message

sacredblack wrote:

> Ger <No.### [at] ThankYou> wrote:
>> Hi Steve,
>>
>> A trick that I personally have used before is to average frames.
>> Either use a linear average so every frame contribute the same amount to
>> the resulting frame, or use a sin-based average.
>>
>> Linear:
>>
>> (Frame 1 + Frame 2 + Frame 3) / 3 = new frame
>>
>> Sin based:
>>
>> (sin(45) *Frame 1 + sin(90) * Frame 2 + sin(45)*Frame 3) / 2.41 = new
>> frame
>>
>> --
>> Ger
> 
> Interesting. Though this looks something like averaging the actual image
> generated ?? Possibly to fix flicker caused by fast moving objects. Not
> sure.
> 

Exactly. Assuming you have the whole animation done, as in all frames
rendered, you can average frames 1, 2 and 3 to create a "new" frame 2.

For example, assume pixel (3,3) is "1" in frame 1 and "0" in frame 2, and
"1" again in frame 3, averaging it will make it a bit more the "0" in frame
2 and less then "1" in the other frames.

Averaging also lets you work on tiny bits of the frame, like just section
(10,10) through (20,50) and it lets you decide how much weight you give the
"other" frames. ie. use 20% frame 1, 100% frame 2 , 20%frame 3 to make the
new frame 2. Or the extreme other way. 100% frame 1, 0% frame 2 and 100%
frame 3 to make the new frame 2. 
Also, you can "fade in - fade out" the averaging so it would only be applied
to the frames 10 through 20 and not the rest.

> The problem I have (which isn't really clear on my first post) is a
> problem with POVRay rendering detail at only 1 pixel size which changes
> every frame making detailed areas that are small (due to location from
> camera) appear to flicker (there's probably a better word to describe this
> problem these days).
> 
> Though I will give your suggestion a go.
> 
> Steve.

-- 
Ger

Post a reply to this message

Hi Ger,

Some really interesting stuff here.

Now how do I go about doing this. It's not the sort of thing I would do in
Sony Vegas - would I do it in VirtualDub or AviSynth ? Maybe in POVRay ?

Cheers,

Steve.

Ger <No.### [at] ThankYou> wrote:
> sacredblack wrote:
>
> > Ger <No.### [at] ThankYou> wrote:
> >> Hi Steve,
> >>
> >> A trick that I personally have used before is to average frames.
> >> Either use a linear average so every frame contribute the same amount to
> >> the resulting frame, or use a sin-based average.
> >>
> >> Linear:
> >>
> >> (Frame 1 + Frame 2 + Frame 3) / 3 = new frame
> >>
> >> Sin based:
> >>
> >> (sin(45) *Frame 1 + sin(90) * Frame 2 + sin(45)*Frame 3) / 2.41 = new
> >> frame
> >>
> >> --
> >> Ger
> Exactly. Assuming you have the whole animation done, as in all frames
> rendered, you can average frames 1, 2 and 3 to create a "new" frame 2.
>
> For example, assume pixel (3,3) is "1" in frame 1 and "0" in frame 2, and
> "1" again in frame 3, averaging it will make it a bit more the "0" in frame
> 2 and less then "1" in the other frames.
>
> Averaging also lets you work on tiny bits of the frame, like just section
> (10,10) through (20,50) and it lets you decide how much weight you give the
> "other" frames. ie. use 20% frame 1, 100% frame 2 , 20%frame 3 to make the
> new frame 2. Or the extreme other way. 100% frame 1, 0% frame 2 and 100%
> frame 3 to make the new frame 2.
> Also, you can "fade in - fade out" the averaging so it would only be applied
> to the frames 10 through 20 and not the rest.
>
> --
> Ger

Post a reply to this message

sacredblack wrote:

> Hi Ger,
> 
> Some really interesting stuff here.
> 
> Now how do I go about doing this. It's not the sort of thing I would do in
> Sony Vegas - would I do it in VirtualDub or AviSynth ? Maybe in POVRay ?
> 
> Cheers,
> 
> Steve.
> 

I don't know of any software out there that can do this. I rolled my own.
It's not that much of a problem to write something for it. 
Time permitting I 'll have look at the sources and see if I can clean it up
somewhat and make it more user friendly. Currently I just hardcode a lot
depending on what I need at the moment.

-- 
Ger

Post a reply to this message

I have managed to improve the problem quite a bit by upping the antialiasing
which of course knocks the render times out but it's definately an
improvement.

Far as the image mixing algorithm goes I have done a very basic version of
this to create slower timelapse film effects. A simple mix 50% of frame 1
and 2 to make new frame 2.

Still interested in the code though.

Steve.

Ger <No.### [at] ThankYou> wrote:
> sacredblack wrote:
>
> > Hi Ger,
> >
> > Some really interesting stuff here.
> >
> > Now how do I go about doing this. It's not the sort of thing I would do in
> > Sony Vegas - would I do it in VirtualDub or AviSynth ? Maybe in POVRay ?
> >
> > Cheers,
> >
> > Steve.
> >
>
> I don't know of any software out there that can do this. I rolled my own.
> It's not that much of a problem to write something for it.
> Time permitting I 'll have look at the sources and see if I can clean it up
> somewhat and make it more user friendly. Currently I just hardcode a lot
> depending on what I need at the moment.
>
> --
> Ger

Post a reply to this message

Hello POV Community,

I made an animation, as well, with a complex 3D object. And I had also these 
"pre-warpspeed" light effects. Looked terrible. Also v3.6...

I used radiosity for that animation.

Greetings,

Sven




"sacredblack" <lis### [at] amongstmyselvescom> schrieb im Newsbeitrag 
news:web.4457243449bbdcf3c36de1cf0@news.povray.org...
> Hi,
>
> This is my first post but I have used POVRay since the DKB (is that right 
> ?)
> days for all sorts.
>
> I've come across this problem before but for the life of me I can't 
> remember
> if there is a cure.
>
> The Problem: I'm doing a spinning object towards camera animation of about
> 2000 frames. The object is quite small to start with. The object is
> reasonably complex and therefore all the small polygons flicker due to
> there size (we are talking probably only a pixel at this stage). The
> animation is fine once it starts to fill the frame.
>
> Any ideas on how to get around this one ?
>
> I've fiddled with the render qualities but with no luck - I did improve it
> by turning of reflections but I WANT reflections.
>
> I'm using POVRay 3.6 (I'm sure it'd be the same on all versions though) 
> and
> I've been converting the rendered TGA files into a
> uncompressed AVI - so compression artefects aren't the problem.
>
> Cheers,
>
> Steve.
>
>
>

Post a reply to this message

Ger <No.### [at] ThankYou> wrote:
> sacredblack wrote:
>
> > Hi Ger,
> >
> > Some really interesting stuff here.
> >
> > Now how do I go about doing this. It's not the sort of thing I would do in
> > Sony Vegas - would I do it in VirtualDub or AviSynth ? Maybe in POVRay ?
> >
> > Cheers,
> >
> > Steve.
> >
>
> I don't know of any software out there that can do this. I rolled my own.
> It's not that much of a problem to write something for it.
> Time permitting I 'll have look at the sources and see if I can clean it up
> somewhat and make it more user friendly. Currently I just hardcode a lot
> depending on what I need at the moment.
>
> --
> Ger

You can do this in POV-Ray.  Create an image-mapped plane so that the frame
just fills the camera FOV, then use an average texture map.  I do this all
the time to fake focal blur on an image-mapped background. Of course, you
may lose some quality re-rendering an image, I haven't tried comparing
before/after on a single frame.

Mike

Post a reply to this message