Alain <kua### [at] videotronca> wrote:

> > Alain <kua### [at] videotronca> wrote:

> >>> Thomas de Groot <tho### [at] degrootorg> wrote:
> >>>> On 12-4-2013 15:03, s.day wrote:
> >>>>> Would be nice to see a radiosity version of this image as well (I assume the
> >>>>> lighting is ambient currently?)
> >>>>
> >>>> Strange you say this. This *is* a radiosity version ;-)
> >>>>
> >>>> Currently:
> >>>>
> >>>>      radiosity {
> >>>>        pretrace_start 0.08
> >>>>        pretrace_end   0.004
> >>>>        count 50, 500
> >>>>        nearest_count 10, 5
> >>>>        error_bound 0.6
> >>>>        recursion_limit 2
> >>>>        low_error_factor .3
> >>>>        gray_threshold 0.0
> >>>>        minimum_reuse 0.010
> >>>>        maximum_reuse 0.1
> >>>>        brightness 1
> >>>>        adc_bailout 0.01/2
> >>>>        normal off
> >>>>        media off
> >>>>        always_sample off
> >>>>      }
> >>>>
> >>>> Thomas
> >>>
> >>> Oops.. sorry, I guess looking at the inside of the windows it shows radiosity
> >>> effects, I think the shadows of the buildings on the road and to a certain
> >>> extent the shadows on the walls in many areas look too consistent, I would
> >>> expect them to darken a bit as they get into corners etc..
> >>>
> >>> I assume you have ambient_light set to zero in the scene? (looking at the
> >>> darkness inside the windows would point to this being set I guess).
> >>>
> >>> Will look more closely before I comment again ;-)
> >>>
> >>> Sean
> >>>
> >>>
> >>
> >> Rendered with version 3.7, so, ambient get automativaly turned OFF as
> >> soon as radiosity is activated.
> >> You can tell it use version 3.7 when you see double values after count
> >> and nearest_count, as well as the presance of maximum_reuse.
> >>
> >>
> >> Alain
> >
> > If you have heard the saying ignorance is bliss, then I must be very happy ;-)
> >
> > I have not tried the new double values on 3.7 do they make much difference to
> > performance? (always looking for ways to speed up a render).
> >
> > Sean
> >
> >
> >
>
> The second value for count set a larger direction pool for the radiosity
> sampling. It should not have any important effect on the speed, but can
> affect the quality. In some cases, it allow you to use a smaller count
> value, making the render faster. If used, it MUST be larger than the
> first value. Those who use it seems to tend to use a value at least 10
> times larger than the first one.
>
> The double nearest_count can affect the quality and the speed. The first
> value set the maximum bound to be used in areas where the samples have
> more variation. The second value is the minimal value to be used in
> areas where everything is prety uniform, like a large, plain wall.
>
> maximim_reuse set the largest distance any sample can be reused. It's
> grosly a ratio of the width ov the scene.
>
> If you use a smaller pretrace_end value, you often can do with more
> relaxed settings elsewhere. The default of  0.04 is often much to large,
> I usualy use 0.01 or 0.005. low_error_factor also play a large role in
> reducing the sampling done during the final trace and a small value can
> greatly reduce artefacts on multi-core systems. Keep it at or under the
> default value of 0.5.
>
>
> Alain

Wow, thanks Alain, you have just supercharged the radiosity gathering stage of
my renders. I need to do a comparisson for quality, I usually run a no focal
blur/AA render to gather the radiosity data then reload this data with pretrace
set to 1. The radiosity render was running at about 5 hours and with these
settings is now taking about 7 minutes!

Will run the final high quality trace now to see if it looks as good as my 5
hour trace. Oh the hours I have wasted ;-)

Sean

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