What's the differnece between alternate class features and substitution levels?

[digiman619]

I'm a Pathfinder player nowadays, but I was recently leafing through my old 3.x PDFs and found substitiution levels in one book and alternate class features in another. Are theses functionally the same thing? Becuase they seem to me from my angle.

[tyckspoon]

They're very similar; the main difference is a Substitution Level can have changes to the base chassis stats, as well - for example, having a different size Hit Die or different skill point allotment than the 'standard' level. ACFs also tend to be available to any member of the appropriate class, while substitution levels are often racially associated; while any Fighter can be a Dungeoncrasher Fighter, only a Warforged Fighter can take the Warforged Fighter substitutions.

[Jowgen]

For completeness, there are also variant classes; like the Thug fighter. There is also a difference in the timing of when you can pick them; i.e. in order you can choose a variant class when first entering, elect to take a substitution level at the right level(s), and lastly ACFs.

Variant classes can be chosen by anyone and just give different features, substitution levels tend to have racial or affiliation requirements and you can only pick one per level at most, and ACFs tend to only have skill requirements (if any requirements at all) and you can pick multiple at a given level.

[OldTrees1]

There are some minor differences:
You can have multiple ACFs at a single level, but can't have multiple substitution levels at a single level.
You can pick different substitution levels each level, but you can't change which variant class you chose.

However as long as you follow the golden rule of ACFs (you can't trade what you don't have) then there is no issue with just handwaving them as all ACFs.

[Endarire]

3.5's substitution levels are sorta like PF's archetypes.

[Forrestfire]

For completeness, there are also variant classes; like the Thug fighter. There is also a difference in the timing of when you can pick them; i.e. in order you can choose a variant class when first entering, elect to take a substitution level at the right level(s), and lastly ACFs.

Variant classes can be chosen by anyone and just give different features, substitution levels tend to have racial or affiliation requirements and you can only pick one per level at most, and ACFs tend to only have skill requirements (if any requirements at all) and you can pick multiple at a given level.

For more completeness, there are actually two types of ACFs:

1. Alternative Class Features (which are presented in plenty of books as part of a class-specific option), and...
2. Class Feature Variants, which are often lumped into ACFs, but are in fact class-agnostic; as long as you have the ability to swap you can swap for it, so you can get any standard class with the ability and have that work.