[Sorcery] Blade of Grass and Tree Bark Armor

[Sorenant]

I've been trying to build the Blade of Grass spell (Magic: Plant Spells p.10) but it has not been easy. First I tried going for Affliction + Innate Attack (based on Weapons of Pure Magic), which failed quite spectacularly. Then I thought about Create (Transmutation Only) but it was so silly I didn't even try. Finally I had a moment of eureka when I saw the perk Charm and realized I might be able to make this spell in a similar fashion to the Imbuements (according to the Under the Hood). I've came up with the following and wish somebody could vet it for anything wrong:

Magery 0 (One-Spell Only, -80%) [1] + Charms [1] + Blade of Grass (H) IQ [4], for a total of [6]
Blade of Grass (Cosmic: No die roll required, +300%; Reduced Fatigue Cost -4, +80%) [29]

I didn't add Magical (-10%) and Visible (-10%) because as far as I understand this advantage, being a normal albeit veiled spell, already includes these characteristics and adding those modifiers would be double dipping.
The value doesn't seem too wrong. Total cost of [29] for an AA cost of [6], right between Imbue 2 and 3 spells.

The Tree Bark Armor was easier, but I'm not confident about the final product:

Affliction 1 (HT; Advantage, Tree Bark Armor, +100%; Fixed Duration, +0%; Increased 1/2D, x10, +15%; No Signature, +20%; Sorcery, ‑15%) [22]
Note: "Tree Bark Armor" is Damage Resistance 5 (Can’t Wear Armor, -40%; Partial, Except Face and Feet, -0%; Accessibility, Back Against a Tree, -10%; Magic, -10%) [10]. Feature: Weights 25lbs.

About the advantage, I considered not having face and feet cover to be quite insignificant for limitation purposes so I gave it no cost reduction. Regarding the Accessibility, trees are not uncommon in general but there will most likely be none in indoor locations (eg dungeon) so I gave it just -10%. I couldn't find any limitation to give items weights except for gadget which seems to not give any point for it so I just made it as a feature.
I have no idea if it's legal without some power equivalent to Essential Wood. I don't think so by RAW but it doesn't make much sense given the supposed way it works (turn bark into essential wood).
Edit: Reading the spell description again, it never says the caster can't wear armor (though normal layering penalty will most likely apply) so I might have to remove the limitation and recalculate. Base advantage would be [23] so the Affliction would cost +13 = [35]

Any help will be much appreciated.

[PK]

I would recommend against using one magic system as the basis for the abilities of another. That way lies recursive madness. Instead, Blade of Grass really does work best if you approach it as creating a sword from (almost) nothing:

Blade of Grass

Keywords: None.
Full Cost: 10 points.
Casting Roll: IQ.
Range: Touch.
Duration: Indefinite.

Statistics: Control Steel 1 (Accessibility, Only for forming the one type of sword that fits the blade of grass, -50%; Link, +10%; Magical, -10%) [5] + Create Steel 1 (Accessibility, Requires and is limited to length of blade of grass, -20%; Link, +10%; Magical, -10%; Reduced Fatigue Cost 1, +20%) [4] + One-Task Wonder (Armoury (Melee Weapons) for sword-making) [1]. Note: Uses sorcery's Indefinite duration instead of lasting for 10 seconds.

I think nailed Tree Bark Armor. My take on it was that it assumed you were unarmored, not that it would add additional armor to your existing armor. However, it isn't really clear in that respect, and I take responsibility for that as co-editor. I'll look into it.

[Sorenant]

Originally Posted by PK

I would recommend against using one magic system as the basis for the abilities of another. That way lies recursive madness.

I suspected so much (it would kill the point of remaking spells as advantages) but this particular spell had so many variables I took the shot.

Originally Posted by PK

Instead, Blade of Grass really does work best if you approach it as creating a sword from (almost) nothing:

...snip...

That's great! Although somewhat obvious in hindsight, I would never have thought about using a combination of Create and Control to achieve the flexibility needed to model this spell as advantage, much less about the One Task Wonder perk.
Actually, this spell contruction seems to flexible it makes me wonder about the possible variants, like this one:

Stick of Wood (or something cleverer)

Keywords: None.
Full Cost: 9 points.
Casting Roll: IQ.
Range: Touch.
Duration: Indefinite.

Statistics: Control Wood 1 (Accessibility, Only for forming the one type of stick that fits the branch, -50%; Magical, -10%) [8] + One-Task Wonder (Armoury (Melee Weapons) for stick-making) [1]. Note: Uses sorcery's Indefinite duration instead of lasting for 10 seconds.

Create Steel wasn't necessary so I cut it out but the cost stayed around the same because Create category moved up to Common. I didn't change the accessibility cost reduction because although this spell is more easily accessible (decent sized branches are not hard to find and you can break it to get smaller ones), the resulting product is not as marvelous as the original spell (sticks are useful but not like a free otherwise expensive sword with a nice cutting edges). Not sure if strictly legal but probably not so bad considering this spell in effect just eliminates improvised weapon penalty...
By sticks I'm thinking, from shortest to longest: Short Baton, Baton, Jo, Quarterstaff and Long Staff. Maybe Tonfa if it's a Y-shaped branch.

Originally Posted by PK

I think nailed Tree Bark Armor. My take on it was that it assumed you were unarmored, not that it would add additional armor to your existing armor. However, it isn't really clear in that respect, and I take responsibility for that as co-editor. I'll look into it.

Good to know I had at least something going on for me.
Now that you mentioned it, I think the fact I ask a fairly "boring" question yet not much later the author and co-editor of the two works I'm basing off gives me an elaborate answer like this is awesome.
By the way is there some bibliography of each GURPS writer? RPGnet has one for individual books but not for Pyramid articles. I could of course check the warehouse page of each one and see the content but doing so for so 100+ volumes is a little daunting.