Whats causing these problems in my pics?

https://www.bris.ac.uk/fluff/u/js0754/PqZ5TGzaXR1p1qwVUZziTw7h/Output5fi
ltpcond.jpg

https://www.bris.ac.uk/fluff/u/js0754/yXeVPEO1wouhibOMrnPbsw7h/Output6pc
ondh.jpg

Whats causing the blotching in the dark corners of objects? Its not so
bad on the first without stained glass but the second is really bad, the
first is just glass glass on the windows, the second is dark stained
glass. Its definitely not low render settings, the one without stained
glass took nearly 24 hrs and the other 8 hrs. Both of these renders were
done with these parameters of rpict

-x 2560 -y 2048 -ar 128 -ad 512 -aa .15 -as 256 -ab 3

Both were done with mkillum using -ab 2 -av 18.9 18.9 18.9 on the
lighter non stained glass and just -ab 2 on the second darker render
with the book. The textures are not low quality, and externally this
renders great, but internally they are really bad in corners?

Whats going wrong?

Cheers John

https://www.bris.ac.uk/fluff/u/js0754/PqZ5TGzaXR1p1qwVUZziTw7h/Output5fi
ltpcond.jpg

https://www.bris.ac.uk/fluff/u/js0754/yXeVPEO1wouhibOMrnPbsw7h/Output6pc
ondh.jpg

Whats causing the blotching in the dark corners of objects? Its not so
bad on the first without stained glass but the second is really bad, the
first is just glass glass on the windows, the second is dark stained
glass. Its definitely not low render settings, the one without stained
glass took nearly 24 hrs and the other 8 hrs. Both of these renders were
done with these parameters of rpict

-x 2560 -y 2048 -ar 128 -ad 512 -aa .15 -as 256 -ab 3

Both were done with mkillum using -ab 2 -av 18.9 18.9 18.9 on the
lighter non stained glass and just -ab 2 on the second darker render
with the book. The textures are not low quality, and externally this
renders great, but internally they are really bad in corners?

Whats going wrong?

Cheers John

John Sutherland wrote:

Whats causing the blotching in the dark corners of objects?
...

-x 2560 -y 2048 -ar 128 -ad 512 -aa .15 -as 256 -ab 3

You have -ad and -as at relatively soft settings, but your -aa is
quite tough in comparison. I assume it is known that -as should
usually be half of -ad, and that increasing both will reduce
splotches in most cases. What is less known is that -aa needs to
be in balance with them as well. The right balance may depend on
your scene, but often when increasing -ad/-as doesn't eliminate all
artifacts, you can take this as an indication that -aa is too small.

In fact, if you want a fast, relatively inaccurate, but sill nice
looking rendering, one possible way to get that is to increase
-aa more than you normally would. In fact, I whish rvu had a
higher default setting for -aa...

-schorsch

···

--
Georg Mischler -- simulations developer -- schorsch at schorsch com
+schorsch.com+ -- lighting design tools -- http://www.schorsch.com/

From: Georg Mischler <[email protected]>
Date: March 28, 2004 7:47:23 AM PST

John Sutherland wrote:

Whats causing the blotching in the dark corners of objects?
...

-x 2560 -y 2048 -ar 128 -ad 512 -aa .15 -as 256 -ab 3

You have -ad and -as at relatively soft settings, but your -aa is
quite tough in comparison. I assume it is known that -as should
usually be half of -ad, and that increasing both will reduce
splotches in most cases. What is less known is that -aa needs to
be in balance with them as well. The right balance may depend on
your scene, but often when increasing -ad/-as doesn't eliminate all
artifacts, you can take this as an indication that -aa is too small.

In fact, if you want a fast, relatively inaccurate, but sill nice
looking rendering, one possible way to get that is to increase
-aa more than you normally would. In fact, I whish rvu had a
higher default setting for -aa...

This seems a reasonable suggestion, so I went ahead and increased the default -aa parameter a bit. I rarely use the defaults, myself, but these will be the new values. (I didn't change rad since the last alteration).

  rvu rpict rtrace
-aa 0.3 0.2 0.15
-ad 256 512 1024
-as 64 128 512

-Greg

Hi,

looks like indirect lighting problems. You might try to increase the different values for the indirect calculation or think about using illums. The scene has quite difficult light sources (e.g. the window with the complex geometry) that make the probability of indirect rays to hit your sky (which seams to be the most important source) rather low... I would try to use illums for the window.

I would really like to know how you mapped the text on the (rather arbitrary) surface of the book? Is the book modeled in a CAD or a result of maths... (which is somehow the same - I know :wink: ?

Maybe some experts follow... indirect errors and these kinds of artifacts are quite a topic here ;-)))

CU+good luck, Lars.

···

--
Lars O. Grobe
[email protected]

He *is* using illums. I hope he takes Georg's recommendations to heart and reports back here...

···

On Mar 28, 2004, at 3:23 PM, Lars O. Grobe wrote:

looks like indirect lighting problems. You might try to increase the different values for the indirect calculation or think about using illums. The scene has quite difficult light sources (e.g. the window with the complex geometry) that make the probability of indirect rays to hit your sky (which seams to be the most important source) rather low... I would try to use illums for the window.

=================
    Rob Guglielmetti
www.rumblestrip.org

may be OT...
again about candel light....
to save some time you should just try the command lampcolor,
you can select geometry, colour and luminous flux... the output is the
radiance...
cheers,
giulio

···

-----Original Message-----
From: John Sutherland [mailto:[email protected]]
Sent: 27 March 2004 00:38
To: [email protected]
Subject: [Radiance-general] Whats causing these problems in my pics?

https://www.bris.ac.uk/fluff/u/js0754/PqZ5TGzaXR1p1qwVUZziTw7h/Output5filtpc
ond.jpg
<https://www.bris.ac.uk/fluff/u/js0754/PqZ5TGzaXR1p1qwVUZziTw7h/Output5filtp
cond.jpg>

https://www.bris.ac.uk/fluff/u/js0754/yXeVPEO1wouhibOMrnPbsw7h/Output6pcondh
.jpg

Whats causing the blotching in the dark corners of objects? Its not so bad
on the first without stained glass but the second is really bad, the first
is just glass glass on the windows, the second is dark stained glass. Its
definitely not low render settings, the one without stained glass took
nearly 24 hrs and the other 8 hrs. Both of these renders were done with
these parameters of rpict

-x 2560 -y 2048 -ar 128 -ad 512 -aa .15 -as 256 -ab 3

Both were done with mkillum using -ab 2 -av 18.9 18.9 18.9 on the lighter
non stained glass and just -ab 2 on the second darker render with the book.
The textures are not low quality, and externally this renders great, but
internally they are really bad in corners?

Whats going wrong?

Cheers John

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