Favored Terrain Shenanigans

[thorin001]

What is the interaction between the Rogue Talent Terrain Mastery and a Ranger's Favored Terrain when the Favored Terrain is acquired after the Rogue Talent?

Example:
Favored Terrain A +2
Gain Favored Terrain B; Favored Terrain A +4, B +2
Gain Terrain Mastery; Favored Terrain A +6, B +4, C +2
Gain Favored Terrain D; Favored Terrain A +8, B+4, C +2, D +?

Terrain Mastery
Benefit: A rogue with this talent gains a favored terrain as the ranger ability of the same name, though the favored terrain ability does not increase with her level as the ranger’s ability does.
Special: A rogue can take this ability multiple times, each time applying it to a new terrain, and granting all other favored terrains a +2 increase to the favored terrain bonus.

Favored Terrain
The ranger gains a +2 bonus on initiative checks and Knowledge (geography), Perception, Stealth, and Survival skill checks when he is in this terrain. A ranger traveling through his favored terrain normally leaves no trail and cannot be tracked (though he may leave a trail if he so chooses).

At 8th level and every five levels thereafter, the ranger may select an additional favored terrain. In addition, at each such interval, the skill bonus and initiative bonus in any one favored terrain (including the one just selected, if so desired), increases by +2.

[alexd1976]

Unless it says otherwise, they don't interact at all, why would they?

Favored terrain from Ranger improves, favored terrain from Rogue does not.

[Emmit Svenson]

By my reading, both the ranger class feature and the rogue talent add favored terrains to a character. Like proficiencies and bonus feats, the favored terrains’ source is largely irrelevant.

When a ranger with one or more favored terrains from rogue talents gains her second (or later) favored terrain from being a ranger, she may put her +2 to a single favored terrain bonus into any of her favored terrains, whatever the source.

When a rogue with one or more favored terrains from ranger levels gains her second (or later) favored terrain from rogue talents, she increases all her other favored terrain bonuses by +2, whatever their source.

Your example should be revised because the first time a rogue takes Terrain Mastery they get no bonuses to their other favored terrains.

Gain Ranger Favored Terrain (Lvl 3): Terrain A +2
Gain Ranger Favored Terrain (Lvl 8): Terrain A +4, B +2 (could also be A +2, B +4)
Gain first Terrain Mastery: Terrain A +4, B +2, C +2
Gain Ranger Favored Terrain (Lvl 13): Favored Terrain A +6, B +2, C +2, D +2 (or whatever)
Gain second Terrain Mastery: Favored Terrain A +8, B +4, C +4, D +4, E +2

[thorin001]

The way I read Terrain Mastery is that every time you select that talent you gain +2 to all other favored terrains, including the first time.

[Archaeik]

thorin001 wrote:

The way I read Terrain Mastery is that every time you select that talent you gain +2 to all other favored terrains, including the first time.

I relatively agree with you, if only to homogenize the situation of Rogue 2/Ranger 3 for every order of levels you take.

The real cheese, however, is stacking the talent by taking them as feats while progressing other things like Horizon Walker.