Re: ctrl_occlusion

["Vince Fortin" <vfortin(at)gmail.com>]

Yeah that helps, thanks!

As far as light direction goes it isn't hard to do with an incidence node.
But the other features sound nice, especially if they help cutting on the rendering time.

 

Thanks,

 

Vincent
 

On 9/28/07, Matt <matt.rouleau(at)gmail.com> wrote:

The main advantage, or differance of ctrl_occlusion, like Morten mentionned, is that it can take in account light direction, simulating more accurately what occlusion is trying to "fake", that is a shadow cast from a diffuse light source. The fact that you can attribute a light direction to occlusion adds more realism, in the sense that you can simulate an occlusion coming from a diffuse light source that is of varying sizes, and coming from different directions (basically a cheap area light shadow).

Another advantage is that you can activate color sampling in occlusion, tinting your occlusion with the albedo of the occluded object. A cheated way of achieving this result, but still pretty cool stuff!

Lastly, although I haven't tried it out yet, it can apperently speed up final gathering speed, by "filling in the details" of a cheap final gather sample.. that's the theory anyway...

For more info: http://www.mymentalray.com/mymr_tutorials/tutorials.htm
and check out the ctrl_occlusion link.

As far as other ctrl_shaders, like ctrl_buffer and such, I have had mixed results.... would have to test them more extensively!
ctrl_objectlights exposes a mental ray function, wich permits you to make any geometry an area light source. Kind of cool, but very sluggish! I would rather use FG than this MI shader.

Hope thet helps!

Matt

On 9/27/07, Morten Bartholdy <xsi(at)colorshopvfx.dk > wrote:

It can take light direction into account. Works nice, plus there is more I haven't had time to discover..

 

- MB

 

----- Original Message -----

From: Vincent Fortin

To: XSI(at)Softimage.COM

Sent: Thursday, September 27, 2007 4:58 PM

Subject: RE: ctrl_occlusion

 

Out of curiosity, what are the advantages of using this shader over XSI's own occlusion?

I'm asking because the latest update goes back to May 2006.

 

I'm also wondering about ctrl_buffer (aug 2005) vs. what's in 6.x nowadays.

 

Thank you,

 

Vincent

 

---

From: owner-xsi(at)Softimage.COM [mailto: owner-xsi(at)Softimage.COM] On Behalf Of Matt
Sent: Thursday, September 27, 2007 12:43 AM
To: XSI(at)Softimage.COM
Subject: Re: ctrl_occlusion

 

Thanks Ben!
I'll try this as soon as I get back to work and let you know if it functions correctly. I'm at Adapt this week and wont have much time to try it out! ;)

Pete, as far as version 1.6, after a painfull Google session, here is where I found it: http://www.xsiarabia.com/vb/showthread.php?p=1073
Thank you Arabian XSi dudes!

see ya

Matt

Projet lead/senior cg artist
BuzzImage group

On 9/25/07, Ben Rogall < brogall(at)excite.com> wrote:

I've not used this shader, but in general you can use the same Mental Ray shader dll in XSI and Maya. So if you have a 32 bit dll with a matching spdl, then you should be able to take the 64 bit dll from the Maya version. The important thing is that the parameter list the dll expects has to match the spdl (which should be the case if the version of the plugin is the same). Also it could be an issue if the dll is compiled with a newer version of Mental Ray ( i.e. Maya2008).




--- On Tue 09/25, Pete Edmunds < pete(at)eclipsecreative.co.uk > wrote:

From: Pete Edmunds [mailto: pete(at)eclipsecreative.co.uk ]
To: XSI(at)Softimage.COM
Date: Tue, 25 Sep 2007 15:15:33 +0100
Subject: Re: ctrl_occlusion








i've found a 1.7 version for 64 bit machines but its for maya its not
of any help is it?
http://forums.cgsociety.org/showthread.php?p=4647521#post4647521

anyone know where i can get hold of 1.6 for xsi? all we have here is
1.1

Mathieu Bertrand wrote:

Matt
wrote:

Hey Dude!


Things are good, pretty busy for the coming months.. kind of like last
year at this time!


For ctrl_occlusion, I have version 1.6 (is your version more recent?),
wich doesn't support 64 bit machines... that is kind of the problem. If
we had access to the source code, we could do something to fix the
problem, but seems that it is not an open source shader. But works fine
for now, gives some very kick ass results! I guess I will have to
pester Etienne so he can code a custom shader that does sensibly he
same thing! ;)


Say hello to Sebas, make sure he's eating his broccoli!


Matt


On 9/24/07, *Mathieu Bertrand* < mbertrand(at)productionsmaj.com
> wrote:


Matt wrote:

> Hey everybody!

>

> Anybody know if an open source version exists of
ctrl_occlusion for

> xsi? An equivalent shader, or at least an up to date version
of it

> would also be nice. It is an occlusion shader that takes into

account

> the direction of a selected light source. Hard to find, but
well

worth

> it.

>

> Thanks!

>

> Matthew Rouleau

>

> Projet lead/senior cg artist

> BuzzImage group


Salut Matt, ça va?

Hows everything at buzz?

I've got ctrl_occlusion installed on my 6.5 over here and it seems
to

work fine, if thats what ur lookin for let me know.


Cheers

Mathieu Bertrand


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Good to ear

Seb says hi to

By the way the guy compiled the ctrl_occlusion shader in 64bit but only
for maya, you can find them here:

http://www.box.net/shared/5rqdsqyitp

might be of some help


Cheers

Mathieu Bertrand


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