NPR - any takers?

[Earl]

Have any of you seen this? John Clements and I were watching these videos in our spare time at work. They are VERY cool. NPR - non photorealistic-renderings. This was a SIGGRAPH paper, but there are movies for download. They are large (one is 63 MBs, the other is 103 MBs). There's also a 2.4 MB PDF file for those unable to watch the videos. Basically it's a system for painting artistic brush strokes on 3D - both for animations and stills. It includes distance determined level of details, silhouette direction detection, and a lot more. It's kinda hard to really describe it. If you're at all interested in seeing 3d turned to true hand-painted art, download these videos. They are encoded in DivX (5), and they are well worth the download.

Links are as follows:
NPR Research Site

NPR -- PDF Document

63 MB Video Demonstration -- REALLY COOL

103 MB Video Demonstration (hidden lines, animation) -- Also REALLY COOL

[This message was edited by Earl Wilson IV on August 25, 2003 at 15:29.]

[Earl]

Have any of you seen this? John Clements and I were watching these videos in our spare time at work. They are VERY cool. NPR - non photorealistic-renderings. This was a SIGGRAPH paper, but there are movies for download. They are large (one is 63 MBs, the other is 103 MBs). There's also a 2.4 MB PDF file for those unable to watch the videos. Basically it's a system for painting artistic brush strokes on 3D - both for animations and stills. It includes distance determined level of details, silhouette direction detection, and a lot more. It's kinda hard to really describe it. If you're at all interested in seeing 3d turned to true hand-painted art, download these videos. They are encoded in DivX (5), and they are well worth the download.

Links are as follows:
NPR Research Site

NPR -- PDF Document

63 MB Video Demonstration -- REALLY COOL

103 MB Video Demonstration (hidden lines, animation) -- Also REALLY COOL

[This message was edited by Earl Wilson IV on August 25, 2003 at 15:29.]

[s.winders]

Cheers Earl


56k here I think I will go for the pdf



Does it involve normal mapping or something?

[jens g.r. benthien]

I guess you know there is a plug-in NPR renderer for Rhino??? It's great stuff, though it doesn't offer too many features.

jens g.r. benthien
designer
http://www.sacalobra.de

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If you don't know how to dream you'll never be a designer.
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[Gary David Bouton]

Thanks for sharing, Earl! I downloaded both AVIs and they were very informative.


My Best,
Gare

[Earl]

Stu,

I know how you feel about that 56K. In fact, I used my ole 28.8 modem long after 56K's came out because my phone line was so crudy that I couldn't even get above 28.8kbps download.

Jens,

Yes! Penguin I think it's called. There's a lot of 'celshaders' out there, many of which are free. LightWave has a few that I can think of: BESM (Big-Eyes-Small-Mouth, designed for anime use), SuperCelShader, among others... However, this new research paper at SIGGRAPH goes beyond what others have done so far. It really is awesome if you're in produce design or technical illustration (I do a lot of tech. illustrations at work). The hidden line features are superb, and the "temporal coherence" makes the stylized rendering perfect for pretty much any situation.

Here's a more detailed explanation (hopefully this will answer your question Stu, about the normal mapping). The NPR system they've researched and implemented involves the ability to define how shadows are displayed, by drawing directly on the object. You can draw some cross-hatches in a 'shaded' region, then it will apply that same technique to all shaded regions. Or, if you draw parallel cross-hatching, it will automatically draw more parallel strokes as you zoom closer to the model. It adds details depending on the level of zoom, and it will simplify the hand-sketched shading when you zoom out. You can specify against this, if you don't want level-of-detail strokes. You can also draw your own, non-parallel shading strokes at various levels of detail, and it will automatically change to what you defined at each level (the transition is smooth - interpolated fading). You can use this for specular highlights too.

You can also define how silhouettes are drawn. If you provide a quick sample stroke, it will apply that to the entire silhouette. It uses a sort of 3d vector for the silhouette - so that when you animate, the silhouette doesn't shift or jitter, it remains where it was drawn in 3d space, and it expands to new silhouettes automatically. When two different silhouette's merge, they remain seperately computed so that each one retains it's unique 3d position (this sounds really weird, but when they demonstrate it in the video, the advantages of this are clear). The silhouettes take on whatever stroke, color, or texture you give as a sample.

Now, they've taken it a bit further. For certain objects (I'll use their examples here), such as a cactus, you may want to draw the spines by free hand. It'll do this, but your strokes will be in 3d, and they will all have coordinates and orientation. When you rotate your model, they rotate as you would expect. No jitters, no movement. However, when doing a technical line drawing with hidden lines perhaps, you don't want your strokes or edges to have 3d coordinates. You want your edges to be redrawn as you rotate so they don't stretch. That sounds confusing, so I'll be more specific. If you use a series of round dots (for a dotted line) as your silhouette edge, you don't want those dots to become oblong when you rotate. However, you DO want your cactus spines to skew so they look truly 3d.

It's funny how simple NPR can be so complex! But with all these features, technical drawings become so much more possible in 3D.

It's like taking SketchUp and giving it oodles of steroids... except this is a free source that will (once it's ready) accept basically any 3d geometry from any application (right now, they already have native import for LightWave objects).

Anyhow...It's a shame there aren't any low-res versions of those videos, because their demonostration really shows how unique their research is.

[Earl]

Sure thing Gary! John Clements and I were both thinking you'd really enjoy this sort of thing.

They have had a toon render engine for a long while.
Carrara 3 will be shipping soon and one of the new features is NPR:

http://www.eovia.com/carrara/whats_new_car3.jsp
neat stuff

[s.winders]

very cool

Thanks for the explanation Earl



Hmm me thinks 2d vector apps are going to be getting a "big" shakeup.

[jens g.r. benthien]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> There's a lot of 'celshaders' out there, many of which are free <HR></BLOCKQUOTE>

I've searched google for free NPR software - without luck. Do you have any links??

jens g.r. benthien
designer
http://www.sacalobra.de

----------//--
If you don't know how to dream you'll never be a designer.
----------//--