os rm equivalent to mr physical sunsky shader? (or similar)

[Anthony Rosbottom]

Hi guys,
A lot of renderers have a sky system that gives you a HDR illumination and environment model that simulates a sky and sun. Even blender internal has one. Does Aqsis or Pixie have a shader that can be used in this way?

Cheers,
Anthony Rosbottom

www.bliz.co.uk

[Chris Foster]

Hi Anthony,

On Tue, Sep 15, 2009 at 9:30 PM, Anthony Rosbottom
<anthony....@gmail.com> wrote:
> A lot of renderers have a sky system that gives you a HDR illumination and
> environment model that simulates a sky and sun. Even blender internal has
> one. Does Aqsis or Pixie have a shader that can be used in this way?

Not that I knew about, and I thought this might be a fun project. I mentioned
it on the aqsis IRC channel and renderguy pointed me at the paper containing
the algorithm which blender apparently implements:

http://www.cs.utah.edu/~shirley/papers/sunsky/sunsky.pdf

from there, a simple search revealed that someone had already written a
renderman shader corresponding to this:

http://www.gamedev.net/community/forums/topic.asp?topic_id=100346

(see the comment half way down by greeneggs)

I didn't try using it or anything, but I guess it does what you want. Let us
know how you go with it :)

Cheers,
~Chris

[>WHiTeRaBBiT<]

Thanks Chris this is very cool B)

I'll keep my eye on this for the future, I don't have access to those
controls in Python but when I port to 2.5 I'll look at adding this to
MOSAIC =)

Eric Back (WHiTeRaBBiT)

On Sep 15, 9:58 am, Chris Foster <chris...@gmail.com> wrote:
> Hi Anthony,
>
> On Tue, Sep 15, 2009 at 9:30 PM, Anthony Rosbottom
>

[Chris Foster]

On Wed, Sep 16, 2009 at 3:53 AM, >WHiTeRaBBiT<
<white...@dreamscapearts.com> wrote:
> Thanks Chris this is very cool B)
>
> I'll keep my eye on this for the future, I don't have access to those
> controls in Python but when I port to 2.5 I'll look at adding this to
> MOSAIC =)

That would be super cool :-)

Looking a bit more closely at the shader, I see that greeneggs has
implemented only the sky colour part of the paper as a surface shader
(which would presumably be applied to some background geometry).

The Shirley paper also includes an extinction and inscattering model,
designed to simulate the haze you normally see at long distances in
the real atmosphere. That part of the model would presumably have to
be implemented as a separate volume shader.

~Chris.

[Anthony Rosbottom]

Thanks for the answers guys. Hmm, I'm [much] more artist than shader writer so was hoping for something already existing.
No worries, Ive got a short film in early preproduction, thats set entirely outside in daylight. Maybe by the time I'm ready to render (a few months at least) Aqsis or Pixie will have a shader for this.

Anthony Rosbottom

www.bliz.co.uk

[Chris Foster]

Hi Anthony,

On Sat, Sep 26, 2009 at 10:05 PM, Anthony Rosbottom
<anthony....@gmail.com> wrote:
> Thanks for the answers guys. Hmm, I'm [much] more artist than shader writer
> so was hoping for something already existing.

The shader I linked *is* compatible with both aqsis and pixie! To
reiterate, just copy the renderman shader source from the post by
greeneggs on this forum thread:

http://www.gamedev.net/community/forums/topic.asp?topic_id=100346

and compile it. (eg, if you've saved the source as sky.sl, invoke
"aqsl sky.sl" to compile for aqsis, or "sdrc sky.sl" to compile for
pixie.)

Let us know if it does what you want. If not, tell us what's missing
and someone here may have time to cobble something together for you.

Cheers,
~Chris.

[Paul Gregory]

> Thanks for the answers guys. Hmm, I'm [much] more artist than shader writer
> so was hoping for something already existing.
> No worries, Ive got a short film in early preproduction, thats set entirely
> outside in daylight. Maybe by the time I'm ready to render (a few months at
> least) Aqsis or Pixie will have a shader for this.
>

Waiting in hope like this will invariably result in disappointment. It
is very very very unlikely that any renderer will just magically gain
a shader that does exactly what you need.

If you have a requirement such as this the best solution is to work
with the people who can help to get the shader written. As Chris
mentioned, the shader he pointed at is already written, and if it
doesn't provide what you need, then ask around here or on the Aqsis
forums/mailing list/irc and I'm sure someone will be able to help.


Paul

[Anthony Rosbottom]

Ok guys, thanks again for the responses. After today, I'm away from a computer for four days so I'll test the shader out and see what it does and doesn't do, when I get back. To be honest, I didn't realise using the shader compilers was so straight forward. There's a bit of a gap in my knowledge of what to do with the compiled shader afterwards, attaching it to the relevent geo etc. but I'll have a good read of the docs when I get back.

I know my involvement in this group has been very sparodic, I've been juggling work and a lot of different non-work things recently. Over the next few weeks I should have more time to get into the renderman world more.

Cheers,
Anthony rosbottom

www.bliz.co.uk

[>WHiTeRaBBiT<]

Hey Anthony,

I took a peek at this shader for future reference and noticed it has a
few issues that will prevent it from compiling without modification. I
decided to make a blend with the modifications to get it compiling and
working with Aqsis and MOSAIC for my reference latter, your welcome of
course to use this yourself also. If you want to use the shader
outside of Blender/MOSAIC just save the skycolor.sl text in Blender's
text editor to your file system ;) Also note I see a lot of
limitations using this shader without better integration with MOSAIC's
existing shaders although I can thing of ways of using it right off by
either applying it to a sphere and creating a global env map from it
or using Aqsis's layered shaders to combine this effect with
MOSAICsurface. Anyway here's fhe file http://www.dreamscapearts.com/Public/skycolor.blend

Eric Back (WHiTeRaBBiT)

On Sep 27, 8:47 am, Anthony Rosbottom <anthony.rosbot...@gmail.com>
wrote:

> Ok guys, thanks again for the responses. After today, I'm away from a
> computer for four days so I'll test the shader out and see what it does and
> doesn't do, when I get back. To be honest, I didn't realise using the shader
> compilers was so straight forward. There's a bit of a gap in my knowledge of
> what to do with the compiled shader afterwards, attaching it to the relevent
> geo etc. but I'll have a good read of the docs when I get back.
>
> I know my involvement in this group has been very sparodic, I've been
> juggling work and a lot of different non-work things recently. Over the next
> few weeks I should have more time to get into the renderman world more.
>
> Cheers,
> Anthony rosbottom
>
> www.bliz.co.uk
>

[Bobby Parker]

Hiya! I don't know if you're aware (you probably are, given your activity in #aqsis) of the older project Neqsus/BtoR for blender to renderman. I've been unable to develop it for some time due to having my time sucked away by other responsibilities and such, BUT...that's all changed. I'm itching to get back to business on Renderman/Blender integration, and I have a host of ideas and tools to get implemented and integrated both with Blender and standalone. All that said, I was curious where you stood in development, and if you'd be willing to accept help from my direction? While I think Neqsus is a great project, Blender has changed dramatically from where it was when I was working with it, and your direction has a more integrated feel...I think a lot of the stuff in Neqsus could be successfully ported to your package, and would probably result in an improved experience over all. 

What do you think?

Bobby Parker

sh0r...@gmail.com

[>WHiTeRaBBiT<]

Hey sh0rtwave glad you stopped by :)

> I don't know if you're aware (you probably are, given your activity in
> #aqsis) of the older project Neqsus/BtoR for blender to renderman.

Of course, your activity and several aspects of BtoR is what inspired
me to do MOSAIC (I think I even used snippets of its code as well)!
For anyone who doesn't know BtoR its an excellent RenderMan script
that keeps things clean and simple through its own very slick GUI ;)

> All that said, I was curious where you stood in development, and if
> you'd be willing to accept help from my direction?

As I stand right now I'm trying to wrap up the bits that are left on
my todo list so I can freeze CVS development on the 2.49b series API.
Then I'll need to do as promised and write at least a basic tutorial
series on how to use the last features before I can move on. Once
that's complete I plan on starting a new SVN repo and rewriting MOSAIC
from scratch taking advantage of the new 2.5 API (using the old code
and concepts as a template to hopefully speed things up). The 2.5 API
is still rough around the edges and is likely to change some more so
I'm hoping to take time to really explore how it works and how best to
take advantage of it (although I already have a bunch of ideas).
Anyway I'd love to talk privately about what you have in mind and how
we might collaborate, drop me an email and lets see what happens
white...@dreamscapearts.com ;)

Eric Back (WHiTeRaBBiT)

> sh0rtw...@gmail.com

[T G]

Bobby!

Yeah we miss Neqsus, at least I have, for it was at it's time one of
the best out there and it was sad to see it fade away, though I for
one to this day consider it as the step towards an evolution of what
exists today - namely Mosaic. Of course we would love to have you on
board, you always have been welcome to help and though I am not a
developer myself I think the more people we have the better. Maybe
even more so when Blender 2.50 comes out and renders everything
obsolete.

So yes by all means stick around!

Ted