"Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> "Jelle Duives" <jel### [at] tnonl> wrote:
> > For a project we're using povray 3.7 rc6 to render a scene. For this scene (a
> > scene with some houses, road & cars) we enabled radiosity in order to get more
> > realistic images. However, when enabling radiosity, we observe a flickering
> > effect of lights, a sort of 'disco' effect. Do you have any idea where this
> > effect comes from and how to reduce this effect?
> >
> > Regards Jelle
>
> clipka <ano### [at] anonymousorg> wrote:
> > Am 05.09.2013 15:57, schrieb Jelle Duives:
> > > For a project we're using povray 3.7 rc6 to render a scene. For this scene (a
> > > scene with some houses, road & cars) we enabled radiosity in order to get more
> > > realistic images. However, when enabling radiosity, we observe a flickering
> > > effect of lights, a sort of 'disco' effect. Do you have any idea where this
> > > effect comes from and how to reduce this effect?
> >
> > Radiosity isn't perfectly accurate, and may over- or underestimate the
> > illumination in any given region of the image; if radiosity samples are
> > not carried over from one frame to the next (which is the default), this
> > may lead to visible random fluctuations in the brightness.
> >
> > If you don't have any moving elements in your scene (i.e. the animation
> > is just a fly-through), this can be avoided by saving and restoring the
> > radiosity samples from frame to frame.
> >
> > If you have stuff moving around, currently the only solution to the
> > problem is to crank up the radiosity quality, to make the fluctuations
> > as "shallow" as possible.
>
> When rad is calculated each time and each scene is differently, even slightly,
> it may come up with different results which causes the flickering effect.
>
> The best way to handle this is to run a scene where you have a maximum view of
> the entire scene (can even try to use some well placed mirrors to help) and run
> with high radiosity settings and save the rad file.  You now should be able to
> run the scene from your original view but load the rad file instead of
> recalculating.
>
> This should work better as the way rad is calculated and determined is dependent
> upon the view when, but when it is save and reloaded, the view no longer matters
> as it is mapped to the scene the same every time regardless of the new camera
> view.  The only thing is areas that were hidden or occluded from the original
> view may not get full rad effects which is why you want a setup that lets you
> see as much of your scene as possible at one time.
>
> I did a trick scene a long time ago (can't find it now) where I ran a rad scan
> with a bunch of coloured balls, but then loaded the rad file with white balls
> for an interesting colour cast effect.
>
> -tgq

First of all thanks for your quick replies! I think that for our daylight
scenarios reusing the radiosity samples is a really good solution, we didn't
think of that yet. However, for our night scenes we have moving cars with lights
mounted 'on' them. In other words, we do not only have moving objects, but
moving lights as well.
Can we also reuse the radiosity samples for this type of scenarios? If not, is
there maybe another solution we can use?

Regards Jelle

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