Whilst creating some slides on Volume Rendering, I finally found an opportunity to use this graphics-flavored version of a silly internet meme. Original found in Two uses of Voxels in LittleBigPlanet 2′s Engine from SIGGRAPH 2011, Advances in Real-Time Rendering. PDF here.
I guess I did it for the lulz.
Impressive short movie.
Update: Youtube link now, since Vimeo was taken down.
Skull, 40000 faces
The little download counter on my super secret world domination dashboard indicates that my thesis code implementations of rendering suggestive contours on 3d meshes has been downloaded over a hundred times. Which tickles my curiosity.
If you’re doing anything fun, serious, silly (or can’t get the damn thing to work at all) with any of my implementations, don’t hesitate to drop me a line. After shedding tears, sweat, blood and probably various other bodily fluids over those implementations during the last year, it would be great to see them ending up in something awesome.
Today I found a way to render the shadow volumes used in the stencil buffer technique I posted about yesterday in Ogre3D. Sometimes all you need is a ninja and three penguins to get a good insight. These are the shadow maps for one single point light source. Notice how the ninja’s katana extends the shadow volume significantly, and how the intersections of the shadow volume with the objects themselves define self-shadowing. Not shown in the picture is how the shadow volumes extend to infinity: this is necessary to be able to use Carmack’s Reverse.
I’ve spent the day reading up on shadowing techniques for real-time rendering which can be used in the Ogre3D project I’m working on. I was not familiar with the details of the shadow volume method using stencil maps. It’s actually pretty clever, and it’s interesting to read how John Carmack (ID Software) developed the depth-fail-method (also known as Carmack’s Reverse) to be able to use the stencil shadow technique in scenes where the player/camera was inside the shadow volume. This is how they established the shadows of those things creeping up behind you in Doom 3.
Here’s a comparison I performed in Ogre3D:
Some good resources (some outdated, but the basics still apply):
I’m working my way through Ogre3D at the moment, to freshen up my C++/Visual Studio skills. I got my student copy from DreamSpark : seems that I’m still registered as a student, and thus qualified for free software - Yoink!. Browsing through the samples, I thought this was a nice touch: the SDK includes an ASCII shader (made in CG), sampling a 3D ASCII cube for values. It seems like a totally backwards way to approach rendering, but I like the silliness of it.
What I’ll be doing with this engine is still a bit uncertain. I’m thinking about implementing my GPU-accelerated technique to draw suggestive contours, cooking up a game from scratch (an educative experience), … we’ll see where it leads!
I’ve bundled my thesis implementations and put them up for download on the thesis code page. The thesis text (and a small overview) can be downloaded from the thesis page itself.
I’d like to thank my promotor, suprvisors and readers for all their efforts, and hope my work and code will be useful for other NPR enthousiasts.
If you want to experiment with Physically Based Rendering, PBRT is the tool to use. Unfortunately, the latest builds (>1.03) have some incomplete instructions on how to build PBRT on your own machine. I’ve built it on Ubuntu 9.10 and 10.04 using the following instructions:
Well, I hope this is a timesaver! 
A new implementation of regular contours got rid of the noise I had in certain models with sharp edges (Stanford Dragon).
Further optimization made it possible to record this demo:
Now, I’m trying to find out why the suggestive contours ‘flicker’ in nearby viewpoints.