Talk: "A Decade of Radiance Tricks"

radiance-general
#1

Hello Radiance users,

Christoph Reinhart asked me to give a talk at the Harvard University Graduate School of Design to help his students better understand the complexities and capabilities of Radiance. I took it as an opportunity to dig deep into my archives and share some of the tricks and techniques that I've learned over the last ~14 years of using Radiance (and reading this list).

The talk was today, and for the benefit of his students and you, here are the slides and my speaking notes. I hope you can all learn at least a little something from this, if only what *not* to do.

http://markjstock.com/gsd_talk_11_notes.pdf
(93 slides, 26 MB)

Mark
mstock@umich.edu

-u+ option and noise
#2

Hi Mark,

Sorry I missed it -- looks like a great talk! Christoph's students are doubly lucky. Thanks for sharing.

-Greg

···

From: Mark Stock <mstock@umich.edu>
Date: April 7, 2011 12:55:21 PM PDT

Hello Radiance users,

Christoph Reinhart asked me to give a talk at the Harvard University Graduate School of Design to help his students better understand the complexities and capabilities of Radiance. I took it as an opportunity to dig deep into my archives and share some of the tricks and techniques that I've learned over the last ~14 years of using Radiance (and reading this list).

The talk was today, and for the benefit of his students and you, here are the slides and my speaking notes. I hope you can all learn at least a little something from this, if only what *not* to do.

http://markjstock.com/gsd_talk_11_notes.pdf
(93 slides, 26 MB)

Mark
mstock@umich.edu

#3

Hi Mark,

thanks for sharing your talk - wonderful compilation of Radiance DO's and
DON'Ts!!

Cheers,
David

···

2011/4/7 Mark Stock <mstock@umich.edu>

Hello Radiance users,

Christoph Reinhart asked me to give a talk at the Harvard University
Graduate School of Design to help his students better understand the
complexities and capabilities of Radiance. I took it as an opportunity to
dig deep into my archives and share some of the tricks and techniques that
I've learned over the last ~14 years of using Radiance (and reading this
list).

The talk was today, and for the benefit of his students and you, here are
the slides and my speaking notes. I hope you can all learn at least a little
something from this, if only what *not* to do.

http://markjstock.com/gsd_talk_11_notes.pdf
(93 slides, 26 MB)

Mark
mstock@umich.edu

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#4

Thanks a lot Mark for today's wonderful presentation and for posting the
slides online! I highly recommend them to everybody on this list.

Christoph

···

-----Original Message-----
From: Mark Stock [mailto:mstock@umich.edu]
Sent: Thursday, April 07, 2011 3:55 PM
To: radiance-general@radiance-online.org
Subject: [Radiance-general] Talk: "A Decade of Radiance Tricks"

Hello Radiance users,

Christoph Reinhart asked me to give a talk at the Harvard
University Graduate School of Design to help his students better
understand the complexities and capabilities of Radiance. I took
it as an opportunity to dig deep into my archives and share some
of the tricks and techniques that I've learned over the last ~14
years of using Radiance (and reading this list).

The talk was today, and for the benefit of his students and you,
here are the slides and my speaking notes. I hope you can all
learn at least a little something from this, if only what *not*
to do.

http://markjstock.com/gsd_talk_11_notes.pdf
(93 slides, 26 MB)

Mark
mstock@umich.edu

_______________________________________________
Radiance-general mailing list
Radiance-general@radiance-online.org
http://www.radiance-online.org/mailman/listinfo/radiance-general

#5

This is great--thanks!

···

On 2011-04-07 12:55:21 -0700, Mark Stock said:

Hello Radiance users,

Christoph Reinhart asked me to give a talk at the Harvard
University Graduate School of Design to help his students better
understand the complexities and capabilities of Radiance. I took
it as an opportunity to dig deep into my archives and share some
of the tricks and techniques that I've learned over the last ~14
years of using Radiance (and reading this list).

The talk was today, and for the benefit of his students and you,
here are the slides and my speaking notes. I hope you can all
learn at least a little something from this, if only what *not*
to do.

http://markjstock.com/gsd_talk_11_notes.pdf
(93 slides, 26 MB)

Mark
mstock@umich.edu

--
Randolph M. Fritz • RFritz@lbl.gov
Environmental Energy Technologies Division • Lawrence Berkeley Labs

#6

Hello Mark,

Many wonderful points of inspirations - thanks for sharing.

Question - page 11 RGB Estimate:
1) Why are you normalising to 0.9 rather than full scale of 1?
2) Why are you squaring the result?

*Terrance Mc Minn

···

***

#7

Terrance,

Those are good questions. In lieu of actual machinery that would return real reflectances, I'd had to come up with a scheme that would get get me close. The basis of the scheme is that RGB screen values aren't reflectances, and they shouldn't be treated as such.

I'll normalize to 0.8 or 0.9 because there is no real "pure white" in real life. Even white paint is rarely over 0.8. And with models with complicated geometry, even 0.8 requires a hefty number of ambient bounces to balance the energy---light really can penetrate into some deep spaces with 0.8. Consider that with a reflectivity of 0.9, only 10% of the energy is killed after every bounce, and you'll see that -ab will need to be prohibitively high to get an accurate rendering. And I choose Radiance for its accuracy, but I haven't got all month for a result.

The squaring of the result is to push the values down closer to zero. Most of the interesting colors are in the 0.2 range, and that's just a hack to get closer. I am sure there's a better way, but that's easy to remember and quick to compute.

Mark

···

On Sat, 9 Apr 2011, Terrance Mc Minn wrote:

Hello Mark,

Many wonderful points of inspirations - thanks for sharing.

Question - page 11 RGB Estimate:
1) Why are you normalising to 0.9 rather than full scale of 1?
2) Why are you squaring the result?

*Terrance Mc Minn
***

#8

The squaring of the result is to push the values down closer to zero. Most

of the interesting colors are in the 0.2 range, and that's just a hack to
get closer. I am sure there's a better way, but that's easy to remember and
quick to compute.

Your informal way is actually quite accurate. The Photoshop RGB values are
intended to be displayed on a screen with a non-linear response curve.
Radiance uses a linear color space and to convert it you have to apply a
"gamma correction" to the color components:

r = R^gamma
g = G^gamma
b = B^gamma

The typical gamma used today is 2.2. So your simple square is not that far
off.

Regards,
Thomas

···

On Sat, Apr 9, 2011 at 10:28 AM, Mark Stock <mstock@umich.edu> wrote:

1 Like
#9

The slides have moved (why was I looking at this now?) to:

http://markjstock.org/doc/gsd_talk_11_notes.pdf

#11

This is an amazing set of examples, Mark! Would you be OK if we linked to your presentation from one of the main radiance-online pages? I think @Andrew_McNeil could take care of that if you don’t mind.

#12

You have my permission to link or copy the slides - either is fine with me. Thank you!

#13

It’s a bit overdue, but I added Mark’s Decade of Tricks presentation to the tricks & trips section here: https://www.radiance-online.org/learning/tips-tricks/

#14

Thanks, Andy – Happy New Year!