Render types

[BluShift]

I don't know if this has been answered, but I certainly couldn't find it anywhere; what is the advantages/drawbacks/differences between the different "types" of rendering? Like MLT, Bidir MLT, Alpha render, etc. I've always used Bidir MLT because it sounded the coolest, and because I actually know what MLT means. But other than that, I don't know what they all mean and what separates one from another

Can anyone "shed some light?" (Sorry )

[remus]

What ive managed to glean over the years:

MLT is the only one which can do caustics.
Path tracing is slightly faster (although i could be wrong, its just a feeling.)
Alpha render is for creating clip masks, so you its not overly important for actually rendering your scenes.

[PureSpider]

MLT is the only one which can do caustics.

No, it just does caustics faster in certain scenes.
MLT "remembers" the valid paths while PT is pure brute forcing

[remus]

That makes sense

[neo0.]

It would be very nice if there was a sticky with common info about the various render types..

[remus]

A little snippet from the manual about hybrid:
"hybrid
If true, direct illumination is sampled with QMC sampling, and indirect illumination with Metropolis-
Hastings sampling."

[benn]

Like PureSpider said - Metropolis light transport finds paths that the light goes along and then send more rays along them (imagine you were looking down a telescope in the scene, it'd be unlikely for light to go through the telescope, but you want Indigo to send more rays down the telescope so that it will resolve faster).

Bi-directional Path Tracing is usually fastest, but if you're scene is complex and is taking far too long -then it's worth going to Metropolis Light Transport, hybrid is usually only used by advanced users, as I'm not too sure of the use-cases myself.