Pathfinder/3.5 compatibility

[Grizzled Gryphon]

Hello! I was hoping someone here would be so kind as to illuminate some things for me.

I am going to start a game soon, and I was thinking of starting a Pathfinder game. How easy is it to use 3.5 info with a Pathfinder game?

Also, which Pathfinder books do I HAVE to have to run a game?

[Machinekng]

The majority of 3.5 is perfectly compatible with Pathfinder, most of the core components of the game have not been changed. Big changes include things like the revised combat maneuver system, how polymorph spells work, and magic item crafting (there are other changes, but those are some major one that come to mind). The only things that really need to be thoroughly revised before porting to Pathfinder are monsters.

As for books, you could use the Core Rulebook (essentially Players Handbook + DM's Guide) and a bestiary, but you can find pretty much all published Pathfinder material on the free, online Pathfinder SRD (http://www.d20pfsrd.com/), which also includes some third-party material, including Dreamscarred Press's excellent Psionics books.

[Grizzled Gryphon]

Ah, so the fact that I have been reduced to only owning the Monster Manual at this time means that I have the one book that needs the most tweaking? This year gets better and better...

[Slipperychicken]

It's really quite easy. Feel free to use any 3.5 material you like.

Remember to reduce skill requirements by 3, because there's no x4 skill points at 1st level.
Acrobatics= Jump+Balance+Tumble
Diplomacy= Diplomacy + Gather Information
Perception= Spot + Listen
Disable Device includes lockpicking.
Linguistics includes forgery.

Combat maneuver checks replace grapple, trip, jump, etc.

Spells are quite different, especially the Polymorph line. Always reference the PF version.

Power Attack looks nerfed at first glance, but was really improved. It gives a better return than in 3.5, also saves you the effort of choosing how much to PA for, and means that spells like True Strike are not disgustingly OP. It's really the only feat you need to be viable in melee.

Always take Deadly Aim (basically ranged Power Attack) for any ranged character. This buff has made ranged combat quite viable in PF.

Multiclassing and Prestige-classing are the exception rather than the norm, as base classes have many more class features than in 3.5. You generally want to stick with one class, maybe with a dip.

[BWR]

The one book you HAVE to have is the Core Rulebook. All the monsters are on the PRD (http://paizo.com/pathfinderRPG/prd/). Most of the details of everything else, including classes, spells, skills, feats, etc. are there as well. Detailed mechanics and explanations of things, such as how to level, how to use skills, combat maneuvers, crafting etc. are in the CRB. Everything else in other books is just extra.

Edit: Recommended books are the Bestiary, Advanced Player's Guide, Ultimate Magic, Ultimate Combat.
However, apart from a few new unimportant subsystems, all the interesting bits are on the PRD.

[Coidzor]

Ah, so the fact that I have been reduced to only owning the Monster Manual at this time means that I have the one book that needs the most tweaking? This year gets better and better...

If all you have is the Monster Manual, then aside from proprietary creatures that Pathfinder can't use, everything's already been updated for you and is available online. So you'd only have to convert the monsters that they can't convert for you.

[Psyren]

If all you have is the Monster Manual, then aside from proprietary creatures that Pathfinder can't use, everything's already been updated for you and is available online. So you'd only have to convert the monsters that they can't convert for you.

And the ones Paizo can't legally convert themselves, in most cases the fans have done the legwork on instead.

[Grizzled Gryphon]

Ah, sweet! Well, thanks for the input, guys. I was supposed to get the PF Core Rule Book for christmas, but that didn't happen. I guess I will be staring at a puter screen for hours on hours...