I was looking for an elegant way to have that effect.
My first idea was a wizard boost like spell in MuVi that would bost the penetration only of a specific form but I was never satisfied with it.
I then taught of a CrVi that would render the spell more perfect but that would imply that penetration is part of a perfect spell.
Then I taught I would combine the two in a PeVi(Form) effect similar to a shell of opaque mysteries.
Here are the guidelines:
Lance of (Name)PeVi(Form) up to level of this spell +4. This spell needs to be cast uppon another. Use the better penetration total of the two. See MuVi Guidelines to see more details.
Ex.
Lance of Light
PeVi(Vi) 20 (Base General,+2 Voice,+0 mom, +0 Ind) has a penetration total of 40 is casted in cooperation of another mage who is casting demon eternal oblivion 30 with a penetration total of 10.
The Demon Eternal oblivion spell would have a penetration total of 40 instead of 10.
the ting is I was never satisfied with the outcome of the old thread. After revision I believe that The effect described above is more balanced & simple.
Some in my troupe say that it is nice but would still be a MuVi effect...
I personnaly Find that MuVi is not well detailed. Spells like wisard boost & anyother spell that augment the feel feel like a CrVi to me.
In 5th ed, there is a merit(Flexible magic) that allows you to add one mag of effect to any formulaic spell. This would imply that you can perfect an hermetic formulaic spell hence why I see all boosting spell as part of CrVi not MuVi.
Taking those from MuVi would leave Muvi with almost nothing.
Flexible Magic allows you to 'vary the effects... to a slight degree'.
This variance can be raise or lower attributes of the spell.
This doesn't sound at all as if one is perfecting the spell, but instead that they are altereing it. I think the sound inference is this virtue is based on Muto, not Creo.
Muto can 'grant or remove properties something cannot naturally have.'
A formulaic spell is a set way to do accomplish a particular effect. It is a rote that repeatably produces one effect.
At the old forum I proposed the idea that Ars magic details "inborn potential', just like characteristics. That is, the guidelines detail the maximum effect possible at a particular level. Therefore one can not achieve more than the magic guidelines detail. With this in mind, spells are constructed at their maximum potential. They aren't average with room for improvment. They are statistically at their max.
With this in mind, to get a spell to accomplish something else (better penetration) I read that Muto Vim would be necessary. This is because one is altering the properties of a set spell. In particular a better version of the spell falls in the realm of 'unnatural'. Again, Muto can 'grant or remove properties something cannot naturally have.'
So I don't see this as involveing Creo Vim at all.
Well to bring up even more of the previous discussion, I believe that penetration is not a function of the spell but rather a function of the casting. You can't link penetration to specific spells, any spell can have any penetration depending upon how well it is cast.
Therefore, I think that creo is the most natural choice for a penetration booster because a specific instance of spell casting is brought closer to perfection.
Sure, muto vim is a combination that doesn't have a lot of spells for it but even muto vim isn't as barren as creo vim.
Upon looking back at the example spell in the first post I have to admit I don't get it.
I think I understand the guide line correctly;
The penetration boosting spell has to be of a sufficent level to affect the target spell.
If the target spell is a valid target, then the target spell uses the penetration of the penetration booster spell instead of its own if the booster spell has higher penetration than the target spell.
Is this what you meant?
What I don't understand is why you made it perdo vim. What is the spell doing? To me it looks like muto vim (change spell A to have penetration B).
I had a hard time sleeping last night and spent a lot of time thinking about this instead of sleeping
Anyway, I see your point. Penetration isn't a spell attribute such a Range/Target/Duration or Spell Description. While I see why you suggest a penetration bonus could occur via Creo Vim, I'm still uncertain.
I'm begining to think that Penetration is a game mechanic, a "to hit bonus" rather than an spell attribute. It's a variable stat that changes everytime because one part of the casting total is a die roll. This variable stat reflects the proficiency of the spell caster "to hit" someone with magic. In some ways it's like confidence, another "to hit bonus" that can't be boosted by in-game mechanics (magic).
However it's not that simple. That's because there is in fact two Penetrations in Ars. There is Penetration, the 'to hit' bonus of a spell, and Penetration the Ability.
It may be that one can not alter the "to hit' bonus with magic, but one might be able to alter the Penetration Ability. However, this enters the touchy realm of magic inproveing abilities. As far as I can tell, Hermetic magic can't improve abilities. This leaves Penetration an unmodifiable stat.
However it's still not that simple. Ars5 p.84 details all sorts of modifiers that can be used to modify the Penetration Ability. In the hands of well prepared player/magus, these modifiers can add a significant bonus to pentration and can add quite a punch to a spell. With this in mind I would be cautious to add any sort of modification to Pentration simply because the clever player can now stack the house rule and the game's canon modifiers to guarantee thier spell will penetrate someone's Parma Magica/Magic Might.
Having set up my cautionary tale, I still have two ideas.
Muto Vim Wizard's Boost adds 5 lvls of power to spell and the story teller is suppose to determine what those extra lvls mean. Is is possible for a variant of this spell to Lower the level of the spell cast? This would increase the spread between Casting Total and Spell Lvl and increase the penetration to hit bonus.
The second idea is an affirmation of Erik's proposal, using Creo Vim to boost the Casting Total of the spell, again wideing the spread between Casting Total and Spell Lvl, which makes Pentration higher.
However this just reminded me, Vis can be used to boost casting totals, which affects Pentration. This means there is yet another way to increase Pentration. So in theory one could stack a house rule, penetration modifiers, and vis, to better Penetration. If one is ok with that fact, then perhaps the the Vis Boost could be the basis of a Creo Vim guideline. Perhaps every Creo Vim Magnitude that exceeds the Magnitude of the Spell adds +2 to Pentration.
So if the spell is Pillum of Fire Creo Ignem 20 and the Creo Vim spell is I dunno, Punch of the Smug Wizard Creo Vim 25. The Creo Vim is one Magnitude higher adding +2 to Pentration. Opinions?
Almost. The effect I'm trying to create is a Shell of Perdo magic that will envelop the other spell. This shell would use it's penetration total to try to get the original spell thru the MR. If it fails, the original spell uses it's own penetration total to try to get it. It would probably be lower & resisted also.
I saw it as a PeVi effect since it is an entropic effect. It does not modify the original spell so it would not be Muto. It could be Creo since it actually creates a shell over the original spell.
While I understand what your saying, I don't think Perdo Vim works this way. If the effect is "to produce a Shell of Perdo magic that will envelop the other spell", then the target is the spell effected. This means some attribute of the effected spell is reduced.
Let's say the spell effected is Pillum of Fire. Then Perdo Vim effects Pillum of Fire, reduceing some attribute of the spell. This means it could dispell PoF or lower the casting total (which would actually Lower pentration). With this in mind, I don't see how targeting PoF would allow one to use the Penetration of Lance of Light to allow the spell through.
That is:
Lance of Light targets Pillum of Fire.
Effect:
Pillum of Fire is either dispelled or the Casting Total is reduced.
Result:
Use Lance of Lights Penetration to allow Pillum of Fire to hit.
I don't see how the result follows given the effect of Perdo Vim. Your suggesting a stat swap that shouldn't follow given the Tech/Form combination.
Now consider that Perdo Vim can reduce the casting total of a spell. If one believes that Creo Vim is the opposite of Perdo Vim, then it's possible to suggest that Creo Vim could increase the casting total of a spell. In my previous post I suggested one way Creo Vim could increase pentration (based on Erik's suggestion). I suppose one could try to hold to the letter of the guidelines and produce another option.
Creo Vim general: Increase the casting total for all magic cast by the target by half the (level + 2 Magintudes) of the spell.
Personally, I prefer the +2 method pentration method over the above suggestion, but I'm trying to suggest ideas based on written rule.
There were people on the Berk List that thought this spell wasn't warrranted by the guidlines. I think not aloowing it is a case of special pleading.
From the perdo vim guidelines on page 160 "dispell effects of a specific type with a level less the the level + 4 magitudes of the vim spell + a stress die"
Putting down the Aegis
R voice
D Momentary
T individual
This spell will remove the parma magica of a character if that character has a parma score of less than (level of this spell +10 + the roll of a stress die)/5. This spell (like almost all others) needs to penetrate in the targets parma magica in order to function. ths spell is only efectatious against hermetic parma magicas not against the might of supernatural creatures.
I'd put this effect in an invested device with a linked trigger and a whole bunch of penetration.
If penetration is a 'to hit' bonus it may not exist 'in-game' and therefore may not be something that can be modified. However we know Parma Magic does exist 'in-game' and has stats that can be altered. Going after Parma Magic seems like the best way to circumvent the issue of altering a 'to hit' bonus. Does that make sense?
Just to be clear I don't think that a perdo vim spell to make a hole in a parma through which your spell can pass through is impossible, I do think that it is a rules headache.
I agree with Chuck that casting a perdo vim spell on your own spell to accomplish this task doesn't seem right.
The more I think about spell penetration from Chuck's point of view the more I'm tempted to introduce an item, a relic from the schism war, which a penetration master has enchanted with a creo/rego mentem effect that reproduces the penetration master's own mindset in the mind of the user. The spell has a duration of sun and it produces warping. It causes the the recipient to act in acordance with a different set of personality traits for the duration of the effect (although they retain their own memories). During the duration if the effect the target has an effective penetration score of 7 (specialization mentem) and they're quite likely to react violently when threatned or presentid with anything that would have reminded the creator of the Diedne.
That's a fantastic idea! I've got a soft spot for Hermetic Relics/Doomsday Machines , but I've never thought of single one that I thought was 'good'.
Didn't the old books detail a follower of Verdi whose items were dangerous to use? I forget his name.
Anyway, what do you imagine this thing looks like? Maybe something Romanesque to clarify the magus was 'not druidic'. Perhaps a Roman Standard or knife. I want to hear more! Who made it, what house did he come from, how was it used during the Schism War. No pressure
, but I've never thought of single one that I thought was 'good'. 
