Archive for the Vector movement Category

Intercept rules

Posted in Boardgames, Intercept, Rules, Vector movement on April 2, 2010 by Mr Backman

I finally gotten around to posting my homebrew spacecombat system Intercept. I have been a Traveller gamemaster since around 1980 or so and as my campaigns always have player owned ships there has been quite a lot of space battles. Originally we used the boardgame Mayday for space combat but when the High Guard rules came out we switched to that, mostly for its more detailed ship design system. When GDW released Striker, a wonderful miniature ground combat system with a highly detailed design system for tanks etc, I decided to do my own design system with more depth than High Guard, more along the lines of Striker. High guard based their designs on dTons and Energy Points and but my design system would be built around cubic metres, metric tons, Megawatts and SI units, similar to Striker. I had my own tech progression and added semi-realistic fusion thrusters, semi-realistic sensors, stealth, hydroponic lifesupport, got rid of the silly plasma and fusion weaponry (these may work in an atmosphere but sure as hell not in space) etc etc. It grew over the years to incorporate aircraft, cars, robots, helicopters, submarines, motorbikes, missiles, grav belts etc and eventually became unwieldy, buggy and really hard to maintain.

In 2009 I started fiddling with a new system from scratch, new rules and new design system specifically made to be simpler to use and easier to play (my daughters use it in our Traveller campaign, aged 11 and 15, so it cannot be that hard to use). That is what Intercept 3 is, a space combat system with some simple design rules for spaceships. I may eventually publish the design system in some form, Excel or text or both, but at the moment I will only have ready-made ships and some simple rules for converting whatever ship designs from whatever rules version you have, Traveller or other, into stats for Intercept. There is a table with weapons for small ships that can be used as guides for conversion from existing designs.


The rulebook, maps, datacard and the optional transparency are available as pdf files for download. Start out small with one ship each, maybe skipping the Sensor rules out the first times if you are unfamiliar with vector movement. There are no counters in the game as the ships are plotted directly on the map (just print more mapsheets as you need them).

Intercept 3.0 space combat is the main rulebook for the game. The last four pages contain reference tables and should be printed separately and given out to each player. They are organised so they can be printed double-sided as you will never need the information on opposite of a page at the same time.

DataCard is used to fill in gameplay values for your ship, two ships fit on each paper.

Maptemplate is the map used both for the double-blind sensor rules and the actual action when Spotted ship duke it out. Print one for each player and one for the actual combat.

TransparencyTemplate is not strictly needed but helps when plotting sensor scans or determining whether your ship is inside a scan or not. It should be printed on OH film so you can see the map beneath.

You can get the whole shebang including the design system from here.

Hello world!

Posted in Vector movement on March 23, 2010 by Mr Backman

Well, this is my very first post for This blog will try to deal with everything related to vector movement but first and foremost to my paper and pencil space combat system called Intercept (and yes, of course it uses vector movement). Vector movement in games has been with us a long time and my contact with it dates back to the early 1970s when I was taught car racing on graph paper by a teacher. For those who have not heard about vector movement or doesn’t quite grasp the subject let me explain it a little:

Vector movement is a way to simulate, in games and elsewhere, how objects move when they are subject to Newtonian movement and as long as we stay well below the speed of light that is true of everything, you, me, our planet and all real world space craft. The reason we lack an intuitive grasp of vector movement is because real world objects are subject to air friction, rolling resistance, muscular resistance etc as all these hide the underlying mechanisms of vector movement. Hovercraft and Curling stones have reduced ground friction to a degree where the Newtonian nature of their movement is clearly visible. Spacecraft, moving in the stark vacuum of space are subject to even less drag, so little as in fact that the Voyager probes sent out in 1977 are still travelling at about the same speed except for the speed loss caused by ‘climbing uphill’ in the gravity well of our Sun.

Doing vector movement in a game goes something like this (not all games do it this way, notably the Attack Vector boardgame)

  1. Measure the speed and direction of you last move
  2. Apply it again as your future drift position.
  3. Apply acceleration from the drift position to get your true future position.
  4. The speed and direction (together we call speed and direction a ‘vector’) is your new move.

Yes, vector movement is this simple and you can do car races or space fights with just pencils and graph paper.