Quote - I was doing some research and found many things.

• I discovered the scanline algorithm, it's something that I don't use and is not efficient and a slow process.

All graphics adapters use AFAIK a scanline algorythm for generating their pictures. So if you have an ATI or NVIDIA graphics adapter, you use a scanline algorythm.

Quote - - The difference between ray tracing and other methods is only the way used to find the illumination sources that contribute to the illumination for each point of an object.
How the source affects the illumination depend on only the illumination model that you use and not if you use ray tracing or not. You can have surface scattering with or without ray tracing.
Ray tracing is able to find more correctly the illumination sources in some cases as with mirrors.

As far as I know, you need ray tracing to get the correct angle of the light for SSS. In a way, translucy in SSS is a kind of refraction. But as I said earlier, you can fake that without ray tracing.

Quote - - IBL is also a fake method, the reason is that the illuminantion in a point not only depend on the intensity, it depend also of the angle of incidence. The image used mapped on the sphere or other shape only contains the intensity information with no angle information, that would be impossible to be stored.
The equivalent of IBL in games are the light maps.

Since the IBL picture is put on a simulated ball arround the szene, you do have angle information.

Light maps have a similar funktion, but they need to be prepared in advance, for your object, your light set and szenery. You could call it a way of saving those light informations.

Quote - -  Ray tracing is unable to do a correct ambient or global illumination, in theory it would be able to do it, but the required computations would last forever.
The only way to do a correct global illumination is with radiosity, then you can use if you want, the radiosity generated maps with or without raytracing.

The earlier mentioned Monte Carlo-Method is a method to simulate radiosity with ray tracing. A true radiosity solution is a very time consuming process, so it is very rarely used. To my knowledge all renderers use simulated radiosity, which can only be done with ray tracing. Of course you could solve the radiosity for you szene and use the result in light maps. But that would not be fast either.

Quote -

• Raytracing is unable to handle particles, smoke, clouds, fire, etc must be done by other means.

Ray tracing can handle particle systems, which are used to display smoke, fire, clouds, water and other things. There are even particle systems for POV-RAY, so you could, if really intrested, even see in source code how that is handled.

If you think scanline is a slow algorythm, as is ray tracing, what kind of algorythm are you comparing ray tracing to?

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

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