Systems Design Analysis - Mech Speed and Turn Rates
In this analysis, I explore the tuning heuristics that define the baseline relationships between mech speeds and turn rates that reinforce the designed weapons system heuristics. Specifically, the analysis will focus on how the existing rates of movement and turning help define discrete conceptual ranges that keeps optimal actions dynamic and interesting.
The purpose of this analysis will be to define the heuristics defined by MW5’s mech speed and agility design, to create a framework or approach to, and to generate migratable concepts to be able to take to other projects and designs.
Bracketing Speed and Agility
It’s likely that the inspiration from the BattleTech combat designs are grounded in World War 2 tank combat. For example, the M-18 tank, which served in WWII through to present day, has a a top speed of 89 kmph on roads, 42 kmph off road, and an effective range of 1000m - all values squarely in the middle of the MechWarrior mech and weapon values. With the game’s ranges, speeds, and tactical considerations grounded, the question then turns to how far did the design push this envelope, and how did they bracket it, and what did they accomplish by doing so?
Mechs are generally split into classes by tonnage. The mech categories in MW5 are light, medium, heavy, and assault mechs, with light mechs ranging between 20-35 tons, medium between 40-55 tons, heavy between 60-75 tons, and assault mechs between 80-100 tons.
For the initial bracketing of mech speed values I looked at the example mechs at 40 and 70 tons, moving at 113.4 kmph and 64.8 kmph respectively. For this section, whenever referring to a medium mech, I will be referring to this 40 ton mech at 113.4 kmph, and the heavy mech as the 70 ton mech at 64.8 kmph.
**Lighter mechs rarely get much faster than the high speed medium mech, but assault mechs do get considerably slower. The speeds outside this window will be discussed later, and explained why they might be better considered through the lens of variant design as opposed to the core tuning heuristics.
To understand the current state of the design in MW5, I used screen recording to determine turn rates of mechs as implemented currently in MW5. I tried to find mechs across the speed brackets with similar engine sizes that typified the extremes between medium and heavy mechs.
A medium mech with a top speed of 113.4 kmph can turn at:
111 deg/s when static
61 deg/s at top speed
A heavy mech with a top speed of 64.8 kmph can turn at:
53 deg/s when static
38 deg/s at top speed
From there, I tabulated the angular speeds of mechs at various speeds and distances.
Legend:
Purple [Less than Diffusion Threshold] - < 1 deg/s
Red [Between Diffusion and Dodge Threshold] - < 2 deg/sec & >= 1 deg/s
Orange [Between Dodge Threshold and Heavy Top Speed Turn Rate] - < 38 deg/s & >= 2 deg/s
Yellow [Between Heavy Top Speed and 55 deg/s] - < 55 deg/s & >= 38deg/s
Green [Between 55 deg/s and Medium Static Turn Rate] - < 111 deg/s & >= 55 deg/s
Blue [Greater than Medium Static Turn Rate] - >= 111 deg/s
** 55 deg/s was used as a round midpoint value between the medium mech’s top speed turn rate and the heavy mech’s static turn rate
Insights - Tracking Speed:
A mech moving at 72 kmph at 5 m can maneuver faster than a static medium mech can track that target.
A mech moving at 72 kmph at 10 m can maneuver faster than a medium mech at top speed or a static heavy mech can track that target.
A mech moving at 93kmph at 20m can maneuver faster than a static heavy mech can track that target.
Insights - Damage Characteristic Transitions:
From video analysis, the game’s cursor was determined to be effectively 1 degree wide. This was derived by observing the assault mech turning at top speed. 1 frame equates to 0.042 seconds, and with a full rotation taking 14.21 seconds, the cursor moved approximately it’s width, resulting it a 1 degree calculation. Factoring a human visual reaction time of roughly 0.25 seconds, that means:
A mech at 1 degree/sec will move a quarter reticle within the reaction duration of a player - potentially exceed precision component targeting - diffusion threshold
A mech at 2 degrees/sec will move a half reticle within the reaction duration of a player - potentially force a miss for a point-fire weapon - dodge threshold
The transitional thresholds are as follows:
A mech at 300 m could cross the dodge threshold at 75 kmph
A mech at 400 m could cross the dodge threshold at 100 kmph
A mech at 500 m could cross the diffusion threshold at 64.8 kmph
A mech at 750 m could cross the diffusion threshold at 97 kmph
Synthesis:
Mech Warrior 5’s weapon and mech designs are dynamic and interesting across a wide variety of matchups because contextual optimality transitions between numerous non-symmetrical windows fluidly, continuously, and irregularly.
Mech turn rates, relative to target speeds, define the closest conceptual windows in combat. These thresholds are relative to any given target’s speeds.
Vulnerability threshold - the range at which a target (at a given target mech speed) will be able to maneuver outside of a mech’s firing cone of fire even at its max turn rate. At this range, the target mech has combat inevitability.
Pin threshold - the range at which a target (at a given target mech speed) will be able to maneuver outside of a mech’s firing cone of fire if the mech has any forward speed. At this range, a mech has to have zero forward speed to prevent the target mech from gaining combat inevitability.
Brawling threshold - the range at which a target (at a given target mech speed) will be able to maneuver outside of a mech’s firing cone of fire if a mech is not continuously employing it’s max turn rate at it’s top speed. At this range, a mech will likely not be able to maintain a continuous rate of fire on target and weapons performance will be most heavily informed by its burst output over its continuous damage rate.
Weapons designs define the more distance conceptual windows in combat. These ranges are more fixed because they’re defined by the weapons system.
Long range (standoff) range combat (>540 m) - The range defined by being beyond the range of the medium laser. The long/standoff range is significant because, even though damage rates are lower, inevitability is highly determined by terrain, positioning, and standoff weapon loadout - all elements that players cannot anticipate prior to a mission. Also, because the inevitability at these ranges are slow enough that closing to within medium range can dramatically change circumstances, this range of combat permits the better situated side to force combat in the context of their preference.
Medium range combat (200 to 540 m) - The range defined by being within the max range of the medium laser and greater than the shift in combat dynamics defined by the short range. The medium range is significant because the rate of damage exchange increases dramatically - the most efficient weapon that many mechs will be carrying a number of are in range, high damage weapons like the AC20 are in range, but also, about at this range, most mechs are outside of the previously discussed dodge threshold, and start slipping inside of the damage diffusion threshold.
Short range combat (<200 m) - Though short range is demarcated at 200 m, in reality, this is a much fuzzier range that could be argued to start at 240 m (SRM max range), or as close as 100m. Short range combat can be defined by:
A significant increase in potential damage (as SRMs and similar short range weapons come into range)
A breakdown of the abilities of weapons to maintain consistent full-rate damage output
The minimum range thresholds of various long range missile style weapons
Mech’s individual component cross-sections entering visual ranges that make target / focus firing much easier and consistent
Combat around terrain / level features that could be used for cover in medium and long ranges are within ranges that targets become equally able to utilize to change combat cadence to their own benefit, making burst damage during windows of opportunity more dominant
The relationship between the extremes makes neither strictly better, meaning lighter mechs aren’t obsoleted by heavier mechs. Between a heavy mech at 64.8 kmph and a medium mech at 115.2 kmph
Long Range: The heavier mech or the faster mech could have the upper hand at standoff ranges because faster mechs can dodge, but heavier mechs can have a wider variety and simply more weapons.
Medium Range: The heavier mech will likely have the ()(&)(&)(&)(*&upper hand if it’s increased durability is supported with a greater medium range damage potential afforded to it by it's tonnage. The faster mech could have the advantage
Short Range: The faster mech will have the advantage in short range combat the greater the difference in speed. The heavier mech will have the advantage in short range combat the smaller the difference in tonnage.
Mech accuracy (arm/torso agility, projectile accuracy, projectile diffusion, active fire duration), loosely relative to target mech speeds, help reinforce the significance of the transition of medium range, where weapons efficacy (based on player ability to stay on target) will improve in a window bounding the medium range’s upper limit.
Considering a nominal mech speed range spanning 18 to 32 m/s (64.8 kmph to 115.2 kmph), the mechs’ turn speeds shape mechs vulnerability characteristics.
Mechs moving faster than 20 m/s can force fast medium mechs to go static inside 10m - fast mechs will not typically find themselves able to be outmaneuvered by opponents.
Mechs moving faster than 27 m/s can force slower heavy mech to go static inside 20m - slower heavy mechs will find themselves vulnerable against faster enemies, unable to utilize their full speed while also maintaining enough turn rate to maximize their damage output.
Mech Designs exist along a spectrum define by the above dynamics, meaning mechs in the middle represent designs that trade off the benefits of the upper speed brackets for the benefits of weapon capacity.
The design is interesting because an intermediate choice doesn’t numerically yield a situation of a “best of both worlds” scenario so much as a degrees of a specialized capability tradeoff.
Designed System Features in MW5
Mech’s full speed turn rates improve faster for top speed value than static values, giving faster mechs a better-than-linear improvement to maneuverability on top of the additional speed benefit.
For Turn Rates
At the lower end of the speed range (or in other words the circumstance that speed can overcome) is defined by turn rates that:
are vulnerable to fast mechs maneuvering to and staying perpetually in their blind spot
forces players to cut their forward speed to stay in combat with the upper half of mech speeds inside 20 m, and the upper quarter of mech speeds inside 10 m
At the top end of the speed range is defined by turn rates that:
do not have blind spot vulnerabilities even at melee ranges to mechs with equal speed
are able to maintain top speed and turn to track mechs crossing the line of site at any speed mech (within this range) at even up to approaching 10 m
For Speeds
The lowest speed of this range results in a maximum rate of angular rotation (from a static target’s perspective) that is near the diffusion threshold (1 deg/s) at 500 m. (Medium Laser Range)
The lowest speed of this range results in a maximum rate of angular rotation (from a static target’s perspective) that is near the dodge threshold (2 deg/s) at 250m. (SRM Range)
The upper speed of this range results in a maximum rate of angular rotation (from a static target’s perspective that is near to crossing the dodge threshold (2 deg/s) at 500 m (Medium Laser Range)
The upper speed of this range results in a maximum rate of angular rotation (from a static target’s perspective) that stays above the diffusion threshold beyond any range that it would be reasonable to deliberately place the reticle over a component continuously
In Summary:
MW5 (and the Battletech franchise) likely used a real life example to bracket their combat design, namely WWII tank combat.
MW5’s speeds in real-time simulation contexts have different observable dynamics as a consequence of what it’s reference speed means at different ranges.
Based around those dynamics, everything from the control feel, weapons designs, and level designs can lean in to mitigate or exacerbate those dynamics.
The values, pushed to double the base value as an upper limit creates an upside relative to those dynamics that were accentuated with turn rate limitations.
The weapons designs, which were already internally differentiated and balanced according to Damage Envelope values, are further differentiated by their relative efficacy against targets of different speeds/weights.
