How to Build: Spell Stabilization Crystal

[jackalope]

I want to make a "spell stabilization crystal" that allows a wizard holding it to cast spells without having to make a skill check.  All of the wizards spells are bought through a VPP that requires Skill Rolls.  Here's the VPP:
 

Wizardry: Variable Power Pool, 23 base + 115 control cost, Powers Can Be Changed As A Half-Phase Action (+1/2), No Skill Roll Required (+1) (167 Active Points); Wizardry (-2 3/4); all slots Gestures (Complex; -1/2), Incantations (Complex; -1/2), Requires A Skill Roll (Skill roll; -1/2), Spell (-1/2), Concentration (1/2 DCV; -1/4), Extra Time (Delayed Phase, -1/2) Cost: 46

I want the crystal to remove the Requires a Skill Roll.  I know there is a way to do this, but for the life of me I can't remember what its called or where to find in the rulebook.  Help?

[L. Marcus]

Variable Limitation, an IAF or Requires A Roll, worth -1/4.

[Chris Goodwin]

Unofficially you'd treat it as somewhat the inverse of a Naked Advantage.  Call it something like a Naked Buy-off.  Figure the difference in cost of the VPP with and without the Requires A Skill Roll Limitation; that difference is the base cost.  Apply whatever Advantages and Limitations to that, and viola.  

[Ndreare]

Both options work, but I always preferred Variable Limitation because of the simplicity of the build for these types of powers.

[Hyper-Man]

Example built via Hero Designer:

 

*Note that some of the values are different than in your original example.

 

67 Wizardry: Variable Power Pool (Magic Pool), 23 base + 115 control cost, Powers Can Be Changed As A Half-Phase Action (+1/2), No Skill Roll Required (+1) (167 Active Points); all slots Gestures (Complex; -1/2), Incantations (Complex; -1/2), Limited Power Spell (-1/2), Variable Limitations (requires -1/2 worth of Limitations; Requires A Roll (Skill roll; -1/2), IAF (spell stabilization crystal; -1/2); -1/4), Concentration (1/2 DCV; -1/4), Extra Time (Delayed Phase, -1/4)

0 1) Magical Bolt: Blast 12d6, Reduced Endurance (1/2 END; +1/4) (75 Active Points); Gestures (Complex; -1/2), Incantations (Complex; -1/2), Limited Power Spell (-1/2), Variable Limitations (requires -1/2 worth of Limitations; Requires A Roll (Skill roll; -1/2), IAF (spell stabilization crystal; -1/2); -1/4), Concentration (1/2 DCV; -1/4), Extra Time (Delayed Phase, -1/4) Real Cost: 23 - END=3
 

Wizardry VPP.hdc

[Markdoc]

There's an alternate, very simple approach. Just build it as a bunch of skill levels for magic rolls, bundled into a focus.

+20 with magic skill (40 active), Focus (OAF: Crystal, -1) 20 active points. Done. You can flavour the number of skill levels, and advantages/limitations to taste (set the crystal in an IAF ring, give it a warm-up time, etc)

 

That way, your caster still has to make a roll, but with a +20 (or whatever you decide on) to his or her rolls, it should be a doddle.

Mechanistically, it has the advantage that it works the same regardless of caster, so that you don't need to re-work out the cost for different-sized VPPs.

 

Otherwise, what the other guys said: variable advantage, allowing you to trade off our skill roll for a focus.

 

cheers, Mark

[jackalope]

Thanks guys.  I think I'm going to go with Markdoc's idea, since it seems to easiest method to make the power transferable -- I intend this crystal to start in the hands of a villain and end up as a reward for the PC wizard.