Hi Sven,
I´m also using the classroom scene as a base.
Slight modifications to the windows to eliminate any terminator
effects
(like FG pushing through showing around the window framing, or also
Arnold
producing shading errors because the geo is singlesided and kept
open there)
basically, cleaning up the meshes and creating UVs.
I don´t think this scene can become photorealistic, the models and
proportions
easily throw you off, even if only subconsiously. Nevertheless, I
also try to
get believable lighting into the scene.
It´s hard.
I´m using Display>ColorManagment>Gamma Values 2.2.
Beware of the physical sky and sun setup together with FinalGathering.
In my personal opinion, it´s implementation it is at least
misleading...
The photographic exposure tonemapping makes it difficult to get a
correct result,
it´s very important to adjust the effect of "burn_highlights" based
on the dialed
in exposure until you get to match the FG preview and the final
render.
It´s best seen on the resulting physical sky color, the
photographic exposure
lensshader tonemaps the sky down too much. This offset is depending
on the
dialed in exposure, you can´t just crank up or down the exposure
without
counteradjusting the burn_highlights slider again.
Please note, I´m not stupid enough to leave the photographic
exposure gamma at 2.2, too.
It´s set to 1.
If I compare the sky&sun with various highdynamic range images on
the environment
and just final gathering without a sunlight, I also have to tone
done finalgathering
Primary Bounce Color and Secondary Bounce Color to 0.4545.
Only then the FG calculation aligns perfectly with the final image
then...
Therefor I think the 1.0 default setting is wrong, the FG
calculation is not affected by
setting 2.2 display gamma settings but needs to be adjusted based
on the Colormanagement
settings.
Not to mention that a first class *.hdr from Paul Debevec on the
environment
(for FG) forces me to throw away the photographic exposure lens
shader to
get to see anything useful. That alone is proof that the sky&sun
setup should not
be taken as willingly aligned and adjusted to artist´s needs... my
personal opinion.
--
In terms of classroom lighting:
I cycled through Irradiance particles, Final Gathering and brute
force methods.
*Irradiance Particles gave me disappointing, large areas moving
noise from frame to frame
*FG can be stable if baked but is still quite difficult to get
splotch free initially
*FG re-calculated per frame using mip_fgshooter is better but not
automatically free of flicker/pumping.
*FG exact gave me crawling noise.
I´m re-setting up the lighting today with a hdr environment and a
mib_cied_d>Infinite light
and unified sampling. That gives me pretty reliable and controlable
results, I would have
liked to use the sky&sun setup but that crap doesn´t even tell you
where North is...
Cheers,
tim
On 29.03.2013 16:49, Sven Constable wrote:
I did tests with the fgshooter a few weeks ago on the classroom
scene. And
yes, its implemention is awful. I used the fgshooter addon too,
its way
easier then.
Btw. I'm also still on the classroom scene and added light and
camera
animation, but I had no time to finish it yet. My goal is to make
it as
realistic as possible and bring mentalray onto its knees.:) Of
course it
has to be flickerfree, what is very hard when the sun is animated
and it
goes to the horizon resulting in only a few very bright spots in
the scene
that has to lit the whole room evenly.
-----Original Message-----
From: softimage-boun...@listproc.autodesk.com
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Tim
Leydecker
Sent: Friday, March 29, 2013 15:36
To: softimage@listproc.autodesk.com
Subject: Finalgathering made less frustrating: mx_fgshooter
Hi guys,
there´s a lot to be desired about mental ray´s implementation and
user
friendliness. I don´t even want to start about having at least an
in depth
documentation including practical examples.
Nevertheless, there´s yet another node that may come in handy but has
probably slipped your radar:
mip_fgshooter
It is supposed to be used to add finalgather calculations from
additional
cameras to your current frame´s fgmap or your *.fgmap in general.
I can´t express how frustrated I am about the implementation in
Softimage.
If you ever had hoped to having to figure out how to enter 4x4
matrixes and
get the thing working yourself, brace for a lot of frustration.
Or use this implementation. Thank you Denis Belyatsky!
http://maxfoxlab.com/mx_fgshooter.html
Hats off.
If you push his implementation hard, you´ll notice the
camera_shooter_cams
will always have to point to the world origin to give realiable
values for
their resulting 4x4 matrixes entered into the render cam´s
mip_fgshooter
item list.
Sofar, I haven´t been able to verify if that is a limitation of
using their
[cameraname].kineGlobal as the source for the 4x4 matrix or if
that is due
to the way the mip_fgshooter node interprets coordinates?
In any case, Denis plugin is a great helper in actually making
flickerfree
FG available to the average user who may sure not be able to
derive and
properly set a 4x4 matrix himself.
In terms of useability, I would have expected mip_fg_shooter to
have a list
entry field where you pick your cameras and that´s it. Like
Lightlinking for
selective light, even SRT coordinates would have been better but
transform
matrixes, really?
That´s defeating the whole point of keeping it simple unless one
could drag
and drop a camera into the Rendertree and at least connect it
directly
there. Which you can´t...
Cheers,
tim
