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Published by Samuel Penn.

Also, see my profile for things that interest me.

Glendale Website - My main web site.

Yags - Main site for yet another game system, a generic GPL'd tabletop RPG.

Yagsbook - Documentation on the Yagsbook RPG documentation format, a Sourceforge project.

Mapcraft - Documentation on world mapping tools, another Sourceforge project.

Midnight Saga - An Ars Magica campaign.

Active Topics

The current topics are currently under active development (relatively speaking).

Yags is Another Game System - Game design notes for Yags, a Free roleplaying game system I use as the core system for most of my campaigns.

Yagsbook - Notes on an XML based documentation system I use for documenting Yags and related campaigns.

Full Thrust - Notes on Full Thrust

Stargrunt - Notes on Stargrunt.



Some rules on how easy it is to spot people and make ranged attacks. This is all really tricky, since I haven't been able to find any decent data anywhere.

Ranged Weapons

A person is assumed to have good vision out to Perception x 100m. If they try to make a ranged attack against someone beyond that distance, then the effective distance is doubled. This can be offset by either aiming, or using scopes. The biggest advantage of scopes is the perception bonus gained.

Types of Scope

Scope Atk Per Range
None +0 +0 300m
x2 +5 +2 500m
x4 +10 +4 700m
x8 +15 +6 900m

Is this sensible? Possibly it should be a multiplier to the perception range, which would make more sense, but give silly results at very high perceptions.


It is assumed that the difficulty to spot someone in an open field is 0.

Distance Modifier
Up to 50m +0
50m+ +5
100m+ +10
200m+ +20
400m+ +30
800m+ +40
1600m+ +50
3200m+ +60

Remember that when trying to spot someone beyond Perception range (P * 100m), then the difficulty is doubled. This makes raw Perception important, whilst still allowing the Awareness skill be useful for spotting hidden things at short range.

If someone is trying to hide, then the base difficulty is their Per * Stealth as long as there is some cover. If cover is poor, then halve the stealth roll.


Type of cover Modifier
None, flat floor x0
Grass field x0.5
Field, bushes or crops x1
Good cover (50%) +10
Excellent cover (90%) +20

In rough field, it is assumed that you are not actually hiding being a bush or tree, but there are plenty of other distractions which make it harder to notice you. You may also have partial cover which isn't as good as 50%.


If the target is moving, then the spot difficulty is halved.

yags/vision.txt · Last modified: 2015/02/04 22:40 (external edit)