The Rules of Invention
This document provides an outline of the rules and procedures for inventions found in GURPS Basic Set. It is no substitute for reading those rules. Inventors and gadgeteers should be intimately familiar with the rules in detail, and should refer to this sheet only as a quick guide.
Definitions
Invention: “realistic innovation at the inventor’s tech level – or one TL in advance of that, at most” (Basic 473).
Gadgeteer: “larger-than-life inventor who can build more fantastic gadgets” (Basic 473).
Gadgeteering Advantage: “lets you design gadgets quickly, and makes it easy to realize higher-TL innovations (Basic 57).
Weird Science: “crackpot scientific theories that are far ahead of their time” (Basic 228).
Required Skills
Required: Design skill from Engineering Triad (B190) or similar appropriate skill. For example, sse Engineering (Electronics) to design battery-powered gadgets or Engineering (Electrical) to design devices that use broadcast power.
Bonus: Weird Science skill allows +5 to any "sufficiently weird" invention.
Complexity
The GM assigns Complexity.
| Complexity | Required Skill Level | Retail Price |
|---|---|---|
| Simple | 14 or less | Up to $100 |
| Average | 15-17 | Up to $10,000 |
| Complex | 18-20 | Up to $1,000,000 |
| Amazing | 21 or more | Over $1,000,000 |
Concept Roll
GM rolls vs. Character Skill to determine if theory is testable.
Modifiers:
- -6 if the invention is Simple, -10 if Average, -14 if Complex, or -22 if Amazing.
- Gadgeteer: -0 if the invention is Simple, -2 if Average, -4 if Complex, or -8 if Amazing.
- +5 if you have a working model you’re trying to copy
- +2 if the device already exists but you don’t have a model
- +1 to +5 if the item is a variant on a existing one
- -5 if the basic technology is totally new to the campaign (regardless of TL)
- -5 if the device is one TL above the inventor’s TL
- Weird Science: +5 if the invention is sufficiently weird
On success, inventor has successful theory and may proceed to Prototype.
On failure, inventor knows his theory is bad and may roll again next day.
On critical failure, the inventor thinks he has a workable theory and proceeds to Prototype.
Prototype
Roll vs. inventor’s skill. Use same modifiers as Concept roll, plus:
- +1 per assistant with skill 15+ (max: +4)
Each Prototype roll requires 1d-2 days if the invention is Simple, 2d days if Average, 1d months if Complex, or 3d months if Amazing.
Cost
No bucks, no Buck Rogers. The prohibitive costs of invention demand either a sufficiently wealthy Patron, or personal Wealth 2 (Wealthy) or greater.
See also
Invention, Gadgeteering, and Weird Science. Gadgeteering lets you do invention much faster and cheaper, but not necessarily better.