Titan Mauler and Duel Wielding Double Weapons

[Draco_Lord]

So I am just curious. If a Titan Mauler with the TWF feats took a weapon with double, choose to wield it with one hand, and then took a second one to wield in the other. What happens? Do they just take a -4 on all attack rolls (plus other things obviously) or -6? Is this even viable?

[Florian]

So I am just curious. If a Titan Mauler with the TWF feats took a weapon with double, choose to wield it with one hand, and then took a second one to wield in the other. What happens? Do they just take a -4 on all attack rolls (plus other things obviously) or -6? Is this even viable?

Sorry, I don´t fully understand your question.

The Jutongrip ability of the Titan Mauler archetype allows you to treat a regular 2H weapon like a regular 1H weapon an a -2 penalty to hit.
The regular rules for TWF still apply, so dual-wielding two regular 1H weapon that are not light is at -4 with the added -2 penalty, so -6.

[Florian]

So I am just curious. If a Titan Mauler with the TWF feats took a weapon with double, choose to wield it with one hand, and then took a second one to wield in the other. What happens? Do they just take a -4 on all attack rolls (plus other things obviously) or -6? Is this even viable?

Sorry, I don´t fully understand your question.

The Jotungrip ability of the Titan Mauler archetype allows you to treat a regular 2H weapon like a regular 1H weapon at a -2 penalty to hit.
The regular rules for TWF still apply, so dual-wielding two regular 2h weapon that are turned into 1H weapon that are not light is at -4 with the added -2 penalty, so -6.

Edit: Double weapons are not covered by that class feature at all and don´t gain any further reduction from Jotungrip.

[Dekion]

If your question is, can you use a double weapon in one hand because you have the ability to wield two-handed weapons in one hand, then the answer is yes, at the additional -2 penalty above and beyond two weapon fighting. If your question is, can you get the primary and off hand attacks for each one while they are being wielded one handed, the the answer is no, you just have an extra, extra awkward weapon in each hand. You would, however, need exotic weapon proficiency or a racial proficiency in the weapon to avoid other penalties if it did not fall under the standard proficiencies for your class.