Hi Onno, This project has been years on the back burner precisely because of GURPS TRAVELLER, so it isn't surprising that it would look like it was for Traveller ;)
The thing for me is, to build what I call a Virtual Table Top (VTT) that can encompass the vastness of space, and maintain what amounts to be, a form of "realism" that can be sustained precisely because it is computer driven as opposed to GM driven at a table. Ignoring gravitational pull of the huge masses would be the first phase of "programming" for this VTT, such that it can be added later on when time permits. I've already figured out how to handle ship motion and recording the following: Current Ship location relative to the center of the star system's mass. Polar Coordinates being what they are, are perfect for using the Angle,Distance aspect to describe any point relative to the sun itself. Current Built up velocity: This is relative to the ship's position, in that it records the direction of thrust, and the "vector" of built up velocity in that given direction. This would be the distance the ship has to travel if it does not accelerate, nor has any other forces acting upon it (such as gravity from a nearby planet or gravity from the star itself). Projected Acceleration: Again, this is a vector in that you determine direction of acceleration, and the duration of said acceleration (which then modifies the built up velocity vector). The hard part was being able to add all three aspects together - and I searched in vain for Vector addition using strictly polar coordinates. In the end, I found I had to convert to Rectangular coordinates, do the additions/subtractions, and then convert back to Polar in order to keep the ability to describe various aspects (built up velocity, current location, etc) simple to store. What was lacking was the ability to describe planetary motion for elliptical motion. Your comment about Delta-V is one that I've not given any real thought to just yet, simply because I haven't got the basics fleshed out, which was the purpose of this thread. In theory? That VTT should be able to handle ANY ship design system from GURPS, and should be able to not only track where ships are, where ships are going, etc - but should also be able to track the time it takes to get there, as well as where any-one ship is relative to the other ship. This in turn would permit for keeping track of sensor ranges, and ultimately, combat ranges. For traveler, it would also keep track of the fact that approach vectors might preclude a ship to ship battle because the time taken to change course and vectors would be prohibitive. In the end? It would be a laboratory for actual GURPS TRAVELLER style combats between ships, and would result (I would hope) in a clearer picture of what warship captains would have to contend with. In the end, if this program were finished (either by myself, or by someone who has more talent for programming than I do!), anyone could use it - whether for GURPS or TRANSHUMAN SPACE or even Classic Traveller or any incarnations of Traveller itself. Now, as to the benefits of using elliptical orbits in the simulation? A GM who wants that level of complexity, can let the program determine what is the trajectory a ship has to follow in order to reach any given planet from any location in the star system. If maneuvering in normal space to a given location will take less than 7 days, ship captains might want to use maneuver drives instead of jump drives to reach a given point. If a pirate wants to lay off a planet, but between a desert world and its closest gas giant (for in system refueling, or for commercial refueling craft to skim the gas giant and bring fuel to the main world), the VTT should be able to do that as well. Should ;) -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Onno Meyer Sent: Tuesday, October 11, 2011 6:01 AM To: The GURPSnet mailing list Subject: Re: RE: [gurps] Planetary movement and checking the Math Hello Hal, some suggestions regarding the fundamentals of your project: * If your setting is anywhere close to Traveller, we are talking about sustained acceleration in the 1 to 6 G range. Is there a benefit from simulating planetary movement, or would you be better served to disregard that, and get a simulation for ship movement under thrust? * Delta-V is not an issue. By contrast, most real-world designs are limited more by fuel an by acceleration. * If you want planets to move, what are the benefits from having elliptical orbits? Ships will move in such orbits, but they're accelerating. * Planets are in orbit around the sun, and so are the various vehicles, but does the forces from the sun matter, compared to the thrust of the engines? Regards, Onno _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
