Point clouds for dummies (and mental ray)

[Stefano Jannuzzo]

Hi list, I've published a small point cloud system for mental.
The points are generated from a camera shader, saved in pdc format (so that can be edited) or in the new map format by mental images, and then looked up and interpolated at reading time.
Start from here
http://sjannuz.com/sj_pc/doc/

Stefano

[Robert Chapman]

Nice one Stefano,

this looks like it could be useful!  gonna try baking shadows into hair, instant time saver!

[Morten Bartholdy]

This looks very interesting Stefano!
Thanks for sharing.

MB

--
Best Regards

Morten Bartholdy
3D/VFX Supervisor

[Vincent Fortin]

Am I reading this right... runtime/rendertime input/output for pdc/mrmap?

Mr Jannuzzo, you are awesome :-D

[Adam Seeley]

Hi,

 

This looks great..... what's it for?

 

I'm obviously being a little thick, but when would I use it?

 

Thanks,

 

Adam.

 

 

 

	Adam Seeley Senior Animator, Commercials, UK T: +44 (0)20 7565 1000   E: adam....@primefocusworld.com@primefocusworld.com www.primefocusworld.com

 

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From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Vincent Fortin
Sent: 26 November 2010 15:41
To: soft...@listproc.autodesk.com
Subject: Re: Point clouds for dummies (and mental ray)

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[Halim Negadi]

Great! A piece of renderman in MR, Thank's for sharing Stefano !

[Ahmidou Lyazidi]

takling about point cloud in MR, here is another one :
http://forum.mentalimages.com/showthread.php?t=6925

Cheers
Ahmidou Lyazidi
Director | TD | CG artist
http://vimeo.com/ahmidou/videos

2010/11/26 Halim Negadi <hne...@gmail.com>

[Stefano Jannuzzo]

Yes, that's from Max Tarpini, another Italian, the author of the well known ctrl shader collection, who also helped me for my shaders.
In theory they also should work in Soft 2011, since you can import the shader declaration by their mi files.
I discovered them after I was almost done with mine, but I kept on going, since we have a different approach to the problem, in particular in the way of generating the points. I think he addresses better than me some particular problems (like sss) where I leave more work (and maybe choice) to the user. Anyway, good to have more than one option.
Both methods were made possible by the new (from mr 3.7) map api, a way of storing and reading very large arrays of points, more efficient and fast than the old kd-trees. Mental is also migrating their point set formats (fg maps, photon maps, etc) to a unified map format, which is a very promising ideas. Beside being faster, we shader writers will finally have access to those data set. So, in theory, with the next versions it will be possible for instance to read/edit/rewrite fg/photon maps, which I think is great. A photon map may be physically correct, but so many time you don't care about that, you would just like to be able to "paint" a map and let the surface shader read it.
I am open to suggestions (and so I think Max is on the mental forum). For instance, I am thinking about using the input pdc only to define the points position, but to recompute the mrmap color and normal at each frame. This way, the user could stick a given points distribution over the surface, so fixing the current main limitation I have now (distribution and flickering).
Ciao

[Ahmidou Lyazidi]

Ho, so an ICE node that could write this kind of file may open some doors, no?

Ahmidou Lyazidi
Director | TD | CG artist
http://vimeo.com/ahmidou/videos

2010/11/26 Stefano Jannuzzo <stefano....@gmail.com>

[Vincent Fortin]

Like this?

http://sjannuz.com/sj_pc/doc/sj_pc.19.jpg

I already love it ;-) It's the missing link between ICE and rendering. The camera shader is great but I reckon we could also use StudioNest's PixelParticles for example to generate the cloud. This kind of workflow is also useful to pass data between FX and Lighting, like for illuminating objects with fire with full control over the data. Now let's hope it's fast!

[Mathieu Leclaire]

These shaders are awesome! Thank you very much. Any chance I could get a
peek at the source code?

-Mathieu

[Stefano Jannuzzo]

Thanks, and sure, no problem. I did not publish the code because it's a bit dirty and uncommented, but for those interested just contact me.
Stefano

[John Payne]

Thanks Stefano!  The color bleeding and translucency is fantastic!  

- John

--
John Wade Payne
Animator
johnwadepayne.com
johnwa...@gmail.com