Six Myths About Ray Tracing

http://theorangeduck.com/page/six-myths-about-ray-tracing

by orangeduck • 14 years ago

20 19 14 years ago

voxx• 14 years ago

you can stop posting this now. it wasn't popular the first time, just let it die.

orangeduck• 14 years ago

As the submission hit the front page the site went down and I had to kill the link to prepare the server for a second (I couldn't even SSH in). Spamming wasn't my intention.

its_so_on2• 14 years ago

I can't see the article, so this is not a response.

My favorite FACT (not myth) about raytracing:

the real world is ray-traced.

agumonkey2• 14 years ago

Pixar added raytracing to Renderman, PRMan is still REYES but it has raytracing IIRC.

btw, why no mentions of other rendering approaches ? Stochastic MLT, Frameless ? Raytracing seems a bit oldfashioned to me.

trimbo2• 14 years ago

Hi, ex-visual effects guy here. You didn't really convince me that these are "myths", and get a few things wrong in the process. I'll hit on a few highlights.

"Ray Tracing, which has major issues with memory and cache"

Memory is impossible to make generalizations about with rendering but there are situations where ray tracing can use far less memory than scanline.

Consider if you have a NURBS surface you'd like to render. With a raytracer, you can solve the ray to surface directly. With a scanline renderer, you must tesselate that surface. Or consider a simple sphere. The memory used to define a sphere can be 4 floats -- xyz position and radius. Solving a ray-sphere intersection is as simple as it gets. With a scanline renderer...it's a lot more. And say you have a velocity and want to motion blur it. Raytracer: 7 floats, stochastic sample the rays in time. Scanline render... it's even more RAM.

Renderman is not a pure scanline renderer anymore. It has had raytracing for a long time.

"Almost all animated movies are rendered using RenderMan"

No, all of Pixars are. That's not "almost all". Dreamworks uses a proprietary renderer. Blue Sky uses a pure raytracer for their movies (Ice Age 1,2,3, Robots, Horton Hears a Who). I'm sure others use Mental Ray.

"Without going into the technical details..."

If you're interested in the graphics space, you should really learn a lot more about how and when raytracing is useful and efficient. I've used pure raytracers and pure scanline renderers in production, I by far preferred the pure raytracer. A compromise between the two is best in general.

erichocean• 14 years ago

Sony is using Arnold for their animated films (a path tracer).

trimbo2• 14 years ago

Cool, thanks. I wanted to give them a shout-out but haven't followed the business enough lately to know what they use.

Six Myths About Ray Tracing

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