I might be missing something (which wouldn't be unusual), but if you had a player that wanted to have an 'inventor' character, how would you handle things.

If you had a medieval clockwork inventor wanting to, say, make clockwork grenades from a steampunk setting, would you allow it? Assuming you did (crossing settings doesn't bother you), how would you adjudicate it? How hard would it be? How long would it take? How difficult would the check be?

I just didn't see a lot of direction on how to go about something like that.

treat it like a magic action but prepared ahead of time and using the mechanics skill? so variable difficulty based on the effect he wants, rolling advantages adds in those effects. He can then carry them around and use them as desired, still needing a combat check of course. Or you can have him create them in the moment like the alchemists from Pathfinder and have it all in one check that combines creating it and throwing it.

Come up with a price for their contraption. Have them gather that much in "raw materials" (in theory, of course, an invention should cost more than its raw materials, but we're assuming a lot lost to experimentation). Set a difficulty and have them roll the appropriate skill. On a failure, the investment is lost with no return (though they may be able to spend advantage to recoup some of their losses). On a success, they now have a working prototype, perhaps with a few quirks from uncancelled threat.

If you have access to the Star Wars Edge if the Empire supplement: Special Modifications, it has rules for making items.

Are you using the magic skills already? The easiest way to do this is just to reskin Arcana as Weird Science, and allow your inventor to treat his inventions as spells.

4 minutes ago, Direach said:

Are you using the magic skills already? The easiest way to do this is just to reskin Arcana as Weird Science, and allow your inventor to treat his inventions as spells.

Already doing some of that. The setting is actually medieval superheroes of sorts, and we're using arcana as a generic 'superpower' skill to cover abilities that don't fit in other places. The character in question is a clockwork inventor superhero but would like to be able to 'invent' items from the steampunk setting over time. It feels like something that should be more than just a simple check and spend money to me.

Perhaps you could do it as talents? Make a talent called Eureka! (or whatever), and each time the inventor purchases the talent, he has successfully invented some new device. Or each talent can represent a specific invention, like Eureka! (Grenade) or Eureka! (Steam Pistol), etc., with the more powerful inventions relegated to higher tiers. Although if all the stuff he invents is meant to be for his own personal use, or is only usable by him, I think using the magic system is probably faster and easier.

If you look on the GenCon character sheets floating around, there's a Dwarven Scholar ( Runebound class ) that uses grenades. Judging by her character sheet she uses Mechanics and Alchemy to make them. She has 2 ranks in both skills as well as 2 ranks in medicine.

Her grenades are:

Bottled Lightning, 7dmg, 5crit. Blast 7, Disorient 3, Stun Damage and Limited Ammo 1.

Dwarven Firebombs, 8 damage, 3crit. Blast 6, Burn 2, Limited Ammo 1.