I used to think the difference between raycasting was that Wolf3D used raycasting while a raytracer used raytracing.

Then I read a 3DCG book.

Raycasting is exactly the same as raytracing except that no reflections/refraction effects are created by propagating the ray when it hits an object. Simply, the colour at that intersection point is returned.

quote: Original post by Anonymous Poster

I used to think the difference between raycasting was that Wolf3D used raycasting while a raytracer used raytracing.

Then I read a 3DCG book.

Raycasting is exactly the same as raytracing except that no reflections/refraction effects are created by propagating the ray when it hits an object. Simply, the colour at that intersection point is returned.

No no no no no no no! For a start, raycasting is far cruder, and much much faster... you only cast a ray for each column of the screen. In raytracing you cast a ray for every pixel... e.g in 320*200 you'd cast only 320 rays in raycasting, as opposed to 64000 in raytracing. In raycasting there are far more geometric constraints to your world (for example, normally walls must be orthogonal), whereas with raytracing you can create practically anything you like. Also, raycasting is fast enough to run in real time, raytracing is so slow it's only useful (at the moment) for pre-rendered backgrounds. Things like Myst use raytracing. Also with raycasting you skip alot of the math, and subsequently the shape of your world is very 'limited' . Basically, raycasting is fast, crude, innacurate, and kinda ugly . Raycasting is the exact opposite.



Nick - Head Designer, Llamasoft.net

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Edited by - Llamasoft.net on December 8, 2000 4:38:33 PM