Ray Casting versus Ray Tracing (Volumetric): A Quick and Convenient Comparison

[@linden5480]

Thanks for the explanation, very clear and simple to understand!

[@BobLaramee]

Thanks for watching

[@shreeyaksajjan1200]

Thank you for this quick video! I was very confused when I first came across a paper that used ray casting, since I assumed it's the same as ray tracing.

[@BobLaramee]

Thanks for watching.

[@krgrief]

starts at 1:10

[@manuel_youtube_ttt]

One minute lost in nonsense

[@MrKylePopovich]

really gets going at 3:10

[@roygalaasen]

Oh it is at 1:10 already... shoot.

[@AvnishKumar-it3sf]

Love from India

[@fredg8328]

Let's add more confusion :) Raycasting was the common name of the engine used to render games like Wolfenstein and Doom. The main difference was that in raytracing you cast one ray per pixel, while in these games, you cast only one ray per column of pixels on the screen. Each pixel of this column were then computed by stretching a texture. The rays were not even cast in 3D, as you only needed one ray per column, the game casted them in 2D on the "level map" from the 2D coordinates of the player.

[@schrodle]

Doom is not a raycaster. Doom's rendering is actually closer to modern game engines than it is to Wolf 3D.

[@realcygnus]

cool what about ray marching ?

[@BobLaramee]

I don't know about that marching

[@realcygnus]

@@BobLaramee Got you......I just heard its like the big brother of tracing, in the world of GPU shaders.

[@iamlordstarbuilder5595]

@@realcygnus it isn’t the best for global illumination. It’s an alternative rasterizer to triangles

[@justgame5508]

Ray tracing/casting is used in more than just graphics. Radio-propagation models are usually based on some form of ray tracing

[@daveb4711]

ray tracing: 3:09, ray casting:4:25

[@Domajnik]

thank you

[@BobLaramee]

Thanks for watching.

[@khodahh]

I though Ray casting was also used for Somme effects like sub surface scattering ang volumetric fog rendering for example. Great video!

[@BobLaramee]

An entire book could be written on this topic. Check out the book chapter in the description.

[@lucaya]

I was very impressed by this comparison.

[@BobLaramee]

Thanks. Happy Black Friday!

[@beaumanVienna]

Now that Vulkan has a ray tracing extension, do you guys know if I can use it for ray casting as well?

[@diyajoseph8619]

Thank you!

[@BobLaramee]

Thanks for watching!

[@jamesrockford2626]

are you from Boston?

[@BobLaramee]

James Rockford , yes well done.

[@decrodedart2688]

James Rockford i live in Australia and I could tell haha

[@oLOo0o0oOLo]

Thank you for a lovely explanation! :)

[@BobLaramee]

My pleasure. Thanks for watching.

[@andreaschristianlouk6891]

Thank you for the Explanation..

[@BobLaramee]

Thanks for watching

[@Han-wg8zw]

Really really helpful

[@BobLaramee]

韓汯勳 thanks for watching

[@stefanbanev]

What prohibits (besides time) to reflect/refract ray-forking at each sample for volumetric data (rhetorical ?). Once transfer function has information of speed of light in media the math is straightforward. Apparently volumetric ray tracing may yield an ultimately realistic visualization a way beyond what ray-tracing with surface-boundaries polygonal representation may do.... with millions scalar cores on chip (massive MIMD) it may become doable....

[@BobLaramee]

Some very advanced lighting and shading techniques have been developed for ray casting as well, resulting in some impressive imagery. See the work by Markus Hadwiger et al.

[@md.rasheduzzaman6928]

That was great

[@BobLaramee]

Fashion and Style happy holidays.

[@int16_t]

Wait... ray casting and ray tracing are different? Never knew that.

[@BobLaramee]

Yes. Tricky terminology.

[@SaurabhNair739]

really great..second half is superb..thanx for this video

[@H3000-v7i]

Usually when comparing ray tracing with ray casting, its surface ray casing, which is something different. Should be a bit more clearly expressed.

[@BobLaramee]

Yes, that point could be clearer.

[@BobLaramee]

There certainly has been a lot of great work on lighting and shading for more realistic ray casting. This video describes just the basic, elementary idea(s), not the state-of-the-art in ray casting techniques.

[@chinmaypatil5190]

Can you mention any good research papers or books where the state-of-the-art techniques are explained? And I can't thank you enough for this wonderfully short and succinct explanation of rendering techniques. Good job!

[@BobLaramee]

Thank you Chinmay. Are you looking for state-of-the-art in the ray tracing direction? Or ray casting. Because ray tracing is more in the CG direction. Ray casting in the vis. So the books and papers will be different.

[@chinmaypatil5190]

DataVisBob i am looking for techniques in ray casting. Also, if it's not much of a pain, could you tell me what's your take on rendering techniques especially for VR? I have read papers using both tracing and casting, but I am not able to make out which one gives what advantages. For eg. latency is a big issue in VR and ray tracing, because of it's recursive nature, could result in more realistic renders at the cost of latency.

[@BobLaramee]

For more on state-of-the-art ray casting, I recommend a book called, Real-Time Volume Graphics by K Engel et al., AK Peters/CRC Press, 2006. ISBN-13: 978-1568812663 As for VR rendering techniques, I am not an expert in VR. Perhaps one of our viewers could recommend a book? I'll post if I come across anything.

[@crysicle]

Ray Tracing(Graphics) in physics is called Ray Casting, though generally only hit point, distance traveled, and normal of the surface are needed to calculate. Ray Casting(Graphics) is generally called the same name in physics with an "All" attached to it's functions "RaycastAll". How come there's a name disconnect between these techniques? Furthermore, if you consider what is actually being done, which is casting points, why are these techniques called ray x instead of point x? If you cast a sphere you call it spherecasting, capsule -> capsulecasting, box -> boxcasting so on and so forth, yet if we're casting points they're called raycasting? None of these names match up to what is actually being done. Did someone just name these techniques once and noone bothered to correct it similarly how Native Americans are still being called Indians after hundreads of years?

[@webgpu]

This woman has more sideburns than myself!!!

[@BobLaramee]

Profound. A sexy woman indeed.

[@webgpu]

@@BobLaramee blergh! heheheheh!

[@vladimirvasilev5796]

Way too slow even on 1.5x. The information density is quite low, and trying desparately to hit the 10 minute mark

[@BobLaramee]

I'm a slow speaker.

[@vraimonds]

Well at least there's a speed up option.

[@BobLaramee]

The introductory comments from the legendary Nelson Max from this course would be a big shock for any module in the UK! kzbin.info/www/bejne/oWqxq2WwZs-HfLM

[@antonykoshi7169]

Can you explain ray casting in detail

[@BobLaramee]

Yes! kzbin.info/www/bejne/jmKlo4VpgriGpck

[@sujay2999]

Thanx a ton!

[@BobLaramee]

You're welcome.

[@BobLaramee]

Look! An introduction to Ray Casting by non other then Ken Joy: kzbin.info/www/bejne/d5nTZ396htN-ars

[@chrischoir3594]

Are you from Boston?

[@chrischoir3594]

North shore?

[@BobLaramee]

Correct

[@BobLaramee]

@@chrischoir3594 South shore (Dedham, home of "Champions") ;)

[@chrischoir3594]

@@BobLaramee yeah great place rt 128