[3.5] Familiar confusion

[liquidformat]

So It seems pretty straight forward that if you are a wizard or sorcerer once you take a prc you stop improving your familiar unless that prc explicitly improves it. However, what about improved familiar, it changes the prerequisites to arcane caster level not wiz/sorc level and can be taken once you are in a prc. So does taking Improved familiar divest your familiar class feature from scaling based on wiz/sorc level to all arcane caster levels? I know the obtain familiar functions this way but does Improved familiar do the same?

[Bronk]

No, the caster level prerequisites for Improved Familiar are just so that you qualify for choosing a particular familiar from the list.

[Remuko]

So It seems pretty straight forward that if you are a wizard or sorcerer once you take a prc you stop improving your familiar unless that prc explicitly improves it. However, what about improved familiar, it changes the prerequisites to arcane caster level not wiz/sorc level and can be taken once you are in a prc. So does taking Improved familiar divest your familiar class feature from scaling based on wiz/sorc level to all arcane caster levels? I know the obtain familiar functions this way but does Improved familiar do the same?

just trade on the base familiar for an alternate class feature and then take the obtain familiar feat.

[Elkad]

Improved Familiar read strictly would seem to give you access to the familiar sooner, but it would still use your core level.

So a Wizard1/Beguiler1/Duskblade1 could get a Celestial Hawk, but it would only have the 1st level Wizard bonuses to it's abilities, so couldn't deliver your touch spells for you.

[Blue Jay]

Improved Familiar read strictly would seem to give you access to the familiar sooner, but it would still use your core level.

So a Wizard1/Beguiler1/Duskblade1 could get a Celestial Hawk, but it would only have the 1st level Wizard bonuses to it's abilities, so couldn't deliver your touch spells for you.

This is not a strict reading: this is a liberal reading, which is the exact opposite of a strict reading. The prereq for a Celestial hawk familiar is "arcane spellcaster level 3rd," not "a total of 3 levels in arcane spellcasting classes." Wizard levels don't stack with beguiler levels or duskblade levels, so your example character does not have caster level 3rd in any arcane spellcasting progression.

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But, in answer to liquidformat's question, I agree with Bronk: Improved Familiar uses your full caster level for determining which familiar(s) you qualify for, but PrC levels still won't count towards the abilities on the familiar table (i.e., Int score, natural armor bonus or "special"), because those are still determined by your class level, and your PrC levels explicitly don't count as class levels for that purpose.