[tomvbussel]

This is wrong. Ray tracing simply is a way to determine visibility between two points, just like the Z-buffer. Ray tracing won't produce a color on its own. Path tracing on the other hand is a method which uses ray tracing to solve the light transport integral. It creates paths between the camera and the light using ray tracing and then it calculates the contribution of that path to the image. Most toy ray tracers only handle specular reflection and transmission, and direct illumination. This is called Whitted ray tracing and is probably what you're referring to.

[dahart]

You're probably right, but nobody I know calls it "Whitted ray tracing" unless Turner is there in the room, or some point is being made about or in reference to his paper specifically. ;) In my experience, graphics people generally do mean producing colors for pixels when they say "ray tracing". But I think physicists would assume "ray tracing" means visibility queries and nothing more.

When someone says 'ray tracing' to me today, before they elaborate on what they mean, I assume they're talking about using straight line segment visibility tests probably to make some kind of picture, probably using Monte Carlo techniques, probably for global illumination. So, they might mean path tracing, or one of the (many) other ways to simulate lighting, or my assumption might be wrong, but that's okay because language is fun, and vague, overridden and imperfect terms allow us to have longer conversations. :)

[DonHopkins]

Is the light transport integral isomorphic to what Heckbert's paper [1] refers to as "gratuitous partial differential equations [2]," as explained by Fuller [3]?

>The “begetted” eightness as the system-limit number of the nuclear uniqueness of self-regenerative symmetrical growth may well account for the fundamental octave of unique interpermutative integer effects identified as plus one, plus two, plus three, plus four, as the interpermuted effects of the integers one, two, three, and four, respectively; and as minus four, minus three, minus two, minus one, characterizing the integers five, six, seven, and eight, respectively [3].

[1] http://www.ecse.rpi.edu/~wrf/Teaching/graphics-s2005/heckber...

[2] https://wattsupwiththat.files.wordpress.com/2012/01/bg-equat...

[3] Fuller. R.B. Synergetics. MacMillan, New York, 1975,~. 125.