Is this player correct as to how magic item creation works?

Question

I'm the GM for a new campaign that started with PCs at level 5. One player's PC is an engineer/machinesmith.

The first session saw the player's PC use a pneumatic launcher that the PC had made magical so that when activated—using no charges and without daily limits on its use—the launcher generated an effect like the spell burning hands. Further, the player explained, the PC had made the launcher magical in other ways so that it could also be activated to generate other effects mimicking spells (exact spells escape me), likewise without limits.

The player argued that any object can be made into a wondrous item so there's no real limit except money.

I argued that only a masterwork weapon can be made into a magic weapon, masterwork armor into magic armor, a masterwork shield into both a magic weapon and magic armor, and a masterwork object into a wondrous item. Other items like scrolls, wands, staffs, and rods are specifically created from scratch, serving no other purpose but as magic items.

He replied that any object can be any kind of magic item except that armor, a shield, or a weapon must remain armor, a shield, or a weapon. Besides, the rules say a machinesmith's gadgets can be magical anyway. He also thinks I'm wrong about a masterwork shield being able to be made into both a magic weapon and magic shield, claiming that would break the game.

Questions

• Is the only real limit on a PC's ability to create magic items the PC's wealth?
• Can any object be made into a wondrous item or only masterwork objects?
• Can a magic item that's not armor, a shield, or a weapon have any form the creator desires? For example, can a creator use the feat Scribe Scroll to create a scroll that looks like a staff but functions as a scroll?
• Can a magic shield be made into both a magic weapon and a magic shield?

Answer 1

What's wrong is that you're the GM for that game and apparently you need to make that more clear to this player. Creating custom magic items is done with GM approval. You're not providing enough information for us to tell what specific applications of item creation he's doing that are right and wrong - and that itself is the problem, that you don't know.

Make it clear custom magic items must be approved by you. He needs to clearly explain the proposed item and how he thinks the build rules work on it. Then you should examine the magic item rules and ask specific questions here if you aren't sure about a specific case. Then you tell him yes or no and assign a cost.

In general the magic item creation rules are clearly labeled as "abusable" and "guidelines to follow," it's easy to try to rules lawyer something inappropriate. And that's why they have you.

Answer 2

The guidelines do not require that wondrous items be made from masterwork items. There really aren’t any guidelines for what can and can’t be a wondrous item—that’s the catch-all term for something that isn’t one of the things that has its own rules.

The pneumatic launcher is a weapon, though. It certainly seems like it should be eligible for magic enhancement, but as a weapon. Adding wondrous-item-style benefits to a weapon is... unclear. It just never comes up in the guidelines. Some GMs allow it, some don’t, some allow it but convert the wondrous-item-style benefit to a weapon-style benefit (read: some enhancement-equivalent cost), others just tack on the 50% price premium for combining items. There’s no real standard here, because the guidelines don’t cover it and they’re guidelines to begin with, so GMs can and do modify them as seems appropriate to them.

If the way he’s done this is that he can either shoot the pneumatic launcher, or else just hold it up and use it to cast burning hands, to me it seems reasonable to cost that as a separate wondrous item combined with the pneumatic launcher, e.g. +50% in cost. However, if he’s trying to rig things that he is casting burning hands as he fires the launcher, combining the two attacks into one, then that is more involved and I would definitely be looking to treat that as some kind of enhancement-equivalent cost, e.g. he would have to make it a +1 pneumatic launcher first, and then this would be a +1 or +2 equivalent so he’s paying 4,000 gp or 9,000 gp or whatever for this.

Answer 3

You are not wrong.

To apply weapon enchanting, you must have a masterwork weapon. What is exactly a "weapon" can be discussed but usually it is understood as "something in this list". You can see that shields are considered as weapons and so can be enchanted as such.

The pneumatic launcher isn't listed here but that could be explained by the fact it comes from 3rd Party material. Actually it is clearly stated in the description that it is a weapon, which means you can enchant it with relevant weapon enchants. There is no weapon enchant such as "can cast Burning Hands at will" so adding this go out of ruled material and is submitted to the GM's good-willing. Personally I would allow this: it seems fun without being too powerful, but it's up to you to decide.

Your shield can of course be enchanted as both a weapon and a piece of armor, and costs the price of both enchants. (For example a +1/+1 shield costs 3000gp, counts as a +1 weapon and gives +1 (plus the normal shield bonus) to AC). If that sounds silly to you you can consider that the enchants apply to different parts of the item (as for a double weapon).

About wondrous items the rules are deliberately vague: it is the GM's job to decide about the details. What the rules state are the price of the item's creation, not a precise list of its components. It makes sense to ask for the item's parts to be masterwork items (that can explain a part of the price of the components). You don't have to consider that every single magic item is exactly as stated in the rulebook: maybe some belts of might have a different color, are made of unicorn hairs or are carved with pictures of epic battles. Nothing wrong here, it's just a matter of what the GM decides.

It also seems by the tone of your question that you and your player didn't really spoke calmly about this. Before simply saying he can't do that explain to him that in the setting they are playing magic items must be built out of masterwork items specifically designed for this purpose and that he can't simply enchant whatever he wants, or at least not at his level of power.