Alternate Turn Modes (WARNING: Math/Physics Intensive)

[prestidigitator]

I really don't like that Running has absolutely no Turn Mode unless it takes a Limitation or is bought for a vehicle. I'd really like a different rule, and for lack of something else, I am going to fall back on a physical model. So here's my idea:

 

It takes force to accelerate, decelerate, turn, or change direction in any other manner (okay, all changes in direction or speed are technically accelerations, but we manage them in different fashions, as I point out below). Turning takes a centripital force to balance the centrifugal, "force," which is inertia's tendency to keep you going in a straight line.

 

Fortunately, we often take advantage of properties of our environment in order to manage turning, rather than using the same force-generating mechanisms we use to change speed. For example, on the ground (Running), we take advantage of gravity and the coefficient of static friction to provide the force. In the air (Flight) or water (Swimming), we use our airfoil to divert the medium through which we are moving, thereby generating a reactionary force.

 

On the ground and in the air, the maximum force we can use to turn is often limited. The coefficient of static friction has a theoretical limit of one, so unless we are melting our tires to glue ourselves to the ground, the maximum centripital acceleration (disregarding possible banks in the path of travel and the tendency to roll) is normally, "one G." In the air, the strength and structure of the airfoil normally limits the force to 1-4 Gs for private aircraft (those built as stunt planes, military aircraft, etc., are usually reinforced and/or built specifically to handle much higher forces, but that could be accounted for with Movement Skill Levels bought by the vehicle itself).

 

For a Speed 4 character, which I will take to be a good average as it is normally low for Superheros and high for Heroic characters, the acceleration of gravity is roughly 50 hexes/phase^2 (3 s/Phase and 2 m/hex gives approximately 45 hexes/phase^2 actually). Neglecting a coefficient of static friction which is usually less than one and an airfoil that can normally withstand a couple Gs along with differences in Speed, let's use this value to determine a Turn Mode for any mode of movement.

 

When we restrict turns to 60 degrees, the path becomes a hexagon whose side length is very nicely equal to the radius, so our Turn Mode is identical to the turning radius, which is determined by:

 

    v^2
r = ---
    a

where "v" is the current velocity and "a" is the acceleration. Using this equation and the value of 50 hexes/phase^2 for acceleration, we can build the beginning of a table for Turn Mode based on velocity:

 

v (hexes/Phase)  Turn Mode (hexes)
---------------  -----------------
 1                0.02
 3                0.18
 5                0.5
 8                1.28
 10               2
 13               3.38
 15               4.5
 20               8

and each doubling of velocity should multiply the Turn Mode by four.

 

Then if we allow the application of a Movement Skill Level to halve the Turn Mode, and say that any Turn Mode resulting in less than or equal to half a hex allows unrestricted turning (you could circle indefinitely inside a single hex if you wanted), we have a mechanic we can use for any mode of Movement Power except space travel. For space travel and other Movement Powers bought with a Limitation (not sure of value), the Turn Mode should be based on the amount of acceleration (Combat Velocity, unless Advantages are applied). In that case, the Movement Power's acceleration/Phase should be used in place of 50 hexes/phase^2 for the acceleration of gravity, and we could again generate tables (but I won't here; suffice it to say that Turn Modes will be drastically decreased unless Combat Velocity approaches 50").

 

However, for vehicles (esp. automobiles), it makes sense that Combat velocity is different from acceleration (60 mph could probably be considered still Combat Velocity, but it can take some cars 10-20 seconds to reach that speed!), so I propose that for Running, Swimming, and Flight, acceleration should be half the normal cost, and Combat Velocity the other half (1 CP per hex of Combat Velocity and 1 CP per hex/Phase^2 of acceleration for Running and Flight; 1 CP per 2 hexes of Combat Velocity and 1 CP per 2 hexes/Phase^2 of acceleration for Swimming; Leaping and Gliding have no real inherent acceleration and can ramain at the usual price).

 

Vehicles could also buy Disadvantages giving them a minimum Turn Mode that is based on their size (the length of the vehicle is probably a good default value, but the actual value and the cost of the Disadvantage should probably depend on the vehicle and campaign).

 

I know it is more restrictive than normal turning rules. I'm not sure what to think about that. Any thoughts? Feedback? Other ideas? Thanks!

[prestidigitator]

Re: Alternate Turn Modes (WARNING: Math/Physics Intensive)

 

However' date=' for vehicles (esp. automobiles), it makes sense that Combat velocity is different from acceleration (60 mph could probably be considered still Combat Velocity, but it can take some cars 10-20 seconds to reach that speed!), so I propose that for Running, Swimming, and Flight, acceleration should be half the normal cost, and Combat Velocity the other half (1 CP per hex of Combat Velocity and 1 CP per hex/Phase^2 of acceleration for Running and Flight; 1 CP per 2 hexes of Combat Velocity and 1 CP per 2 hexes/Phase^2 of acceleration for Swimming; Leaping and Gliding have no real inherent acceleration and can ramain at the usual price).[/quote']

Sorry. This part is actually a different subject except that it ties in with the space Flight issue. I should have posted it independently.

[Dust Raven]

Re: Alternate Turn Modes (WARNING: Math/Physics Intensive)

 

I know it is more restrictive than normal turning rules. I'm not sure what to think about that. Any thoughts? Feedback? Other ideas? Thanks!

 

For some reason, I feel I owe it to you to submit 15 or so replies.

 

Unfortunately all I can think to say is that what you've come up with way to complicated for the Hero System. I followed most of it, but you lost me when you started to blend real world physics in with game terms like Phases. Realistically it looks pretty good though.

 

However, the main reason Running has no turn mode is to balance it with Flight. They both cost the same, but Flight as a turn mode (and increases KB) and Running does not have a turn mode. The current rules for creating a turn mode are extremely simple and based on game terms rather than actual physics, but that's okay, because so if falling and falling damage and a bunch of other stuff. The point is it's easy, or at least easier than trying to model reality exactly.

[prestidigitator]

Re: Alternate Turn Modes (WARNING: Math/Physics Intensive)

 

For some reason' date=' I feel I owe it to you to submit 15 or so replies. [/quote']

Heh. No worries.

 

Unfortunately all I can think to say is that what you've come up with way to complicated for the Hero System. I followed most of it, but you lost me when you started to blend real world physics in with game terms like Phases. Realistically it looks pretty good though.

 

However, the main reason Running has no turn mode is to balance it with Flight. They both cost the same, but Flight as a turn mode (and increases KB) and Running does not have a turn mode. The current rules for creating a turn mode are extremely simple and based on game terms rather than actual physics, but that's okay, because so if falling and falling damage and a bunch of other stuff. The point is it's easy, or at least easier than trying to model reality exactly.

Well, most of it was more the rational behind the change than the actual in-system mechanics. The idea was just to make your Turn Mode based solely upon your velocity. The table I showed isn't even necessary if you remember that the Turn Mode for 5" of velocity is 0.5 (the largest velocity, "without," a Turn Mode), and that for each doubling of velocity the Turn Mode is x4. Values in between can just be interpolated (Turn Mode for 10" is 2, and 20" is 8, so we can estimate the Turn Mode for 15" at about 5"). Then each Movement Skill Level cuts your Turn Mode in half, instead of subtracting one from it.

 

One complication I mentioned was that it should be different when your method of turning is tied up with your normal method for acceleration (e.g. Flight in space or the Flight of a helicopter). That could be ignored for simplicity, I suppose.

 

I see what you mean about the difference between Running and Flight. If this method were used, I suppose the costs should be adjusted. Make Flight twice as expensive? I've always thought it was underpriced (easy Flight really only makes sense for four-color comics anyway--everywhere else, being able to fly is really, REALLY advantageous!).

[Labrat]

Re: Alternate Turn Modes (WARNING: Math/Physics Intensive)

 

Why not just switch on an in-house rule where Running needs to apply a turn-mode?

 

Then the Running/Flight cost paradigm could still be justified as this:

 

Flight = 2D Movement + Height Movement Advantage + Extra Knockback Disadvantage

Running = 2D Movement

 

Would this be easier than tracking more math and charts?

[Sean Waters]

Re: Alternate Turn Modes (WARNING: Math/Physics Intensive)

 

I like this, although I am worried about:

 

1: complexity - I don't think it is that complex though, and many people might prefer looking up a turn mode than working it out. Mind you Turn Mode is easy enough to work out at present, and quicker to work out on the fly than the current system.

 

2. practice and balance - it is going to mean that high speeds have impractical turn modes for most tabletop games: not unrealistic, but also not necessarily fun. Perhaps you could reduce your turn mode with an advantage: maybe for a +1/4 you could ahve a turn mode of Move/10 and for +1/2 no turm mode at all.

 

3. powers balance - running and flight are balanced by the turn mode thing - I don't see that the extra KB really balances the vertical element, especially as there is less to hit in the air! Perhaps we could have MOVEMENT 2 points per point, and then advantages and limitations to simulate the different modes: -1/2 for only in contact with a surface (I know they book says -1/4: it's wrong), -1 for only in a specific unusual environment (so you get swimming and swinging), and not on a surface/limited control (-1) for gliding. Teleport would combine (+1/2 - doesn't cross intervening space and -1/2 velocity can't be used for manoeuvres). This woulds allow more customisation of the powers you want. I suppose movement powers are the first instance of the way Talents are built - balancing advantages and limitations to keep active points down and things simple.