does evothaum have a cost

[potestas]

does it cost a mental energy to cast or is it like thaumaturgy where there is no cost because its slow and uses another source of power. Does self sponsored evothaum share the same cost or lack of cost?

[Tedronai]

Evothaum is a subject of some contention.

IMO, "Evocation's methods" means following the Evocation's steps of 'How to Do It' (save for substituting the appropriate Thaum type/descriptor in step 1), including mental stress.

[Sanctaphrax]

Yeah, I'm pretty sure it costs mental stress. Never known anyone to run it any other way.

[potestas]

I can see that for self sponsored magic, but sponsered magic wouldn't that be tapping the power of the sponsor

[Taran]

I can see that for self sponsored magic, but sponsered magic wouldn't that be tapping the power of the sponsor

The power of the sponsor is the magic itself and any debt you incur which translates to anything you'd use to spend a FP on.

So, if you want to boost power by spending a FP, you can take a point of debt instead.  The sponsor covers the extra power.
Or, If you want the sponsor to cover mental stress, you'd take a point of debt.

[Mr. Death]

Thaumaturgy isn't, strictly speaking, no cost. It's no cost so long as you don't go above your Conviction rating for each round of the casting.

Evocation there is always the stress cost, even with sponsored magic.