For a long time I was confused as to what the Shadow Infusion talent actually did, but reading the (shadow) descriptor and special material descriptions for shadowstuff, I have a somewhat better idea.
Off-hand it seems like Shadow Infusion has some of the same functions as the Create Reality ability of the Fey Adept class. But where Create Reality has rather specific rules for how its illusory creatures and objects work, since they reference other spheres directly, Shadow Infusion has some general principles: Shadowstuff objects are as hard and heavy as shadowstuff (rather than being completely intangible), shadowstuff creatures have 1/5th the HP of their fully real counterparts (rather than being intangible figments), and other shadowstuff effects are half as effective if disbelieved (rather than being typically negated outright).
My boggle arises in the case of making illusory creatures and where to pull base numbers from. Suppose Nebulor the Inscrutable has an illusion caster level of 3, and whips up a mighty minotaur as a shadowstuff creature:
1) Should I look up the minotaur in the bestiary and give it 20% of its regular hitpoints?
2) Does the shadowstuff minotaur deal the damage listed in the bestiary by default (halved if disbelieved) - or can it not deal damage despite having "mass", if Nebulor neglected to take the Illusory Touch talent twice?
3) Can a shadowstuff creature perform combat maneuvers (at half CMB if disbelieved)?
4) If a shadowstuff creature is disbelieved, is it still able to flank opponents?
5) If Nebulor wants his shadowstuff minion to perform ability or skill checks (say, busting down a door or picking a lock), should the ability/skill modifier come from the bestiary entry or be based on Nebulor's caster level/casting stat/skill ranks somehow?
Just spoke to the author of the Illusion sphere handbook.
When dealing exclusively with the Shadow Infusion talent, all it is intended to do is allow you to choose to deal lethal or nonlethal damage, and only have a reduced effectiveness on a successful Will save to disbelieve. The part about objects and creatures of the (shadow) descriptor is not meant to apply outside the Shadow Magic feat (decreased hit points with objects from the Creation sphere, companions from the Conjuration sphere, etc. This is because illusions are neither objects nor creatures.
Just spoke to the author of the Illusion sphere handbook.
When dealing exclusively with the Shadow Infusion talent, all it is intended to do is allow you to choose to deal lethal or nonlethal damage, and only have a reduced effectiveness on a successful Will save to disbelieve. The part about objects and creatures of the (shadow) descriptor is not meant to apply outside the Shadow Magic feat (decreased hit points with objects from the Creation sphere, companions from the Conjuration sphere, etc. This is because illusions are neither objects nor creatures.
Many thanks! This does seem to bring Shadow Infusion in line with the individual usefulness of other talents.
I'm left with one little niggle: Taking the Shadow Magic feat requires having either Shadow Infusion or a shadow pool, but actually using the Shadow Magic feat seems to necessitate having a shadow pool. Is the intent that a caster with Shadow Infusion can use a spell point rather than a shadow point to grant herself talents from Shadow Magic?
"The first time you gain a surreal feat you also gain a shadow pool as the fey adept class feature, except it only contains a number of shadow points equal to the total number of surreal feats you possess. This stacks with any other shadow points."
But you can spend spell points if you have Shadow Infusion. That's mostly there for non-Fey Adepts who want to do a lot of shadow magic. XD
Cheers, that completely slipped my mind!