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(TFT) footraces against everything... and what's a dragon?
A gait refers to a particular sequence of lifting and placing the feet
during legged movement (gallop, trot, walk, runb&)
One repetition of the sequence is a gait cycle completed in one gait period
per gait cycle
The inverse of the period is the gait frequency (1/period)
In one gait cycle, each leg goes through exactly one complete step cycle
The gait phase is a value that ranges from 0 to 1 with zero being the
arbitrary starting point of the cycle
The phase is like a clock that keeps going round and round (0b&1, 0b&1, 0b&1
for bipeds) with each individual leg going through a complete step cycle
Each legbs step cycle is phase shifted relative to the main gait cycle
The step cycle is broken into two main stages
Support stage (foot on ground)
Transfer stage (foot in the air)
The amount of time a leg spends in the support stage is the support duration
with the remaining time of the period being the transfer duration
Support duration + transfer duration = gait period
The relative amount of time a foot spends on the ground is called the duty
factor
For a human walking, the duty factor will be greater than 0.5, indicating
that there is an overlap time when both feet are on the ground
For a run, the duty factor is less than 0.5, indicating that there is a time
when both feet are in the air and the body is undergoing ballistic motion
Duty factor = support duration / gait period
The step phase is a value that ranges from 0 to 1 during an individual legbs
step cycle
We can choose 0 to indicate the moment when the foot begins to lift (i.e.,
the beginning of the transfer phase)
The foot contacts the ground and comes to rest when the phase equals 1 minus
the duty factor
Each legbs step cycle is phase shifted relative to the main gait cycle
This phase shift is called the step trigger
The trigger is the phase within the main gait cycle where a particular leg
begins its step cycle
A simple description of the timing of a particular gait requires the
following information
Number of legs
Gait period
Duty factor for each leg
step trigger for each leg
All land based vertebrates evolved from an original btetrapodb ancestor
The tetrapod was like a primitive reptile- closer to a fish
The 4 legs were adaptations of swimming fins and the creature moved on land
by a combination of bpaddlingb with its legs and bswimmingb with itbs spine
All present day quadruped vertebrates are based on the same underlying
construction, but with various adaptations
Even snakes, birds, dolphins, and whales evolved from the ancestral tetrapod
and still show many similarities
Arms
Clavicle
Scapula
Humerus
Radius/Ulna
Carpals
Metacarpals
Phalanges
Legs
Pelvis
Femur
Tibia/Fibula
Tarsals
Metatarsals
Phalanges
Some animals, such as humans and bears walk flat footed (palmate)
Some, like horses and cattle walk more on their fingers (digitate)
Smaller or stockier animals sometimes walk with wide stances (sprawling
gaits) (these include insects, many reptiles, and some small mammals)
Larger animals tend to walk with straighter legs
Muybridge showed that almost all quadrupeds use one or more of the following
gaits
Walk
Amble
Trot
Rack/Pace
Gallop (rotary & transverse)
Canter
The basic slow gait of most quadrupeds is the walk
Very slow walks may involve 3-4 legs on the ground, but normal walks involve
3 legs on the ground with a brief moment with only 2
The duty factor is therefore relatively high (.6 ~ .8)
A typical step trigger for a quadruped walk might be; 0 for hind-left, 0.25
for front-left, 0.5 for hind-right, and 0.75 for front-right
Ambles are like a quicker version of the walk, but are also associated with
larger, slow moving quadrupeds
The duty factor is often in the .5 ~ .7 range, but some horses amble at even
lower duty factors
Elephants use the amble gait exclusively. The front and back legs are often
very close in phase (shifted by around .1 or so)
The gait often involves a noticeable swinging of the body from left to right
A typical step trigger for a quadruped amble might be; 0 for hind-left, 0.2
for front-left, 0.5 for hind-right, and 0.7 for front-right
The trot is a medium paced gait where alternate diagonal legs step nearly in
sync (though often slightly led by the forefoot)
The duty factor is usually relatively low (<.4) and there are moments where
all 4 legs are off the ground (actually, cats sometimes trot at a higher
duty factorb&)
A typical step trigger for a quadruped trot might be; hind-left &
front-right 0 and front-left & hind-right 0.5
The rack or pace has similar qualities to the trot
This gait is considered to be the least comfortable for a rider, but offers
better traction than the trot thus its use for drawing light transport
vehicles like a surrey
Most camels use this as their primary gait
A typical step trigger for a quadruped pace might be; hind-left & front-left
0 and hind-right & front-right 0.5
Unlike the first 4 quadruped gaits the canter is asymmetrical
The canter is a medium speed gait, but a bit irregular and not usually used
for long intervals
Some horses canter as they slow down from a gallop
Sometimes, the timing of the canter is more like .6, .0, .0, .1, with 3 legs
stepping in rapid succession, alternating with the 4th leg
A typical step trigger for a quadruped canter might be; hind-left &
front-right 0, hind-right 0.3, and front-left 0.7
The gallop is the fastest quadruped gait
The gallop involves an alternation between the front and back pairs of legs,
but slightly out of sync
There are several subtle variations on gallops, but they are generally
separated into transverse and rotary gallops
Horses tend to prefer the transverse gallop, as do most other quadrupeds
Rotary gallops involve a circular LR-RL timing (as opposed to the
zig-zagging LR-LR timing of the transverse gallop)
Many dogs use a rotary gallop at high speeds, as do a few other quadrupeds
A typical step trigger for a quadruped transverse gallop might be; hind-left
0, hind-right 0.1, front-left 0.5, and front-right 0.6
A typical step trigger for a quadruped rotary gallop might be; hind-left 0,
hind-right 0.1, front-right 0.5, and front-left 0.6
Gallops can also be broken into either feline or equestrian types, based on
the front/back timing
For equestrian (horse-type) gallops, the timing is like; back-front-pause
After the front legs push off, all four legs are in the air
For feline (cat-type) gallops, the timing is like; front-back-pause
After the back legs push off, all four legs are in the air
This sometimes known as a leaping gait
A typical step trigger for a equestrian gallop might be; hind-left 0,
hind-right 0.1, front-left 0.4, and front-right 0.5
A typical step trigger for a feline gallop might be; hind-left 0, hind-right
0.1, front-left 0.6, and front-right 0.7
Some quadrupeds gallop in such a way that the front and back pairs of legs
are in sync
This is known as a bounding gait
A typical step trigger for a bounding gait might be; hind-left & right 0 and
front-left and right 0.5
Most adult insects are hexapods (6 legs)
For slow movement, some use an off-sync back to front wave gait
For faster movement, most insects use a tripod gait
Occasionally, one encounters insects that run on their back 4 legs or even
only their back 2 (cockroaches can do this as well as my Hymenoptera)
Off-sync back to front wave gait step trigger; hind-left 0, front-right 0.1,
middle-left 0.3, hind-right 0.5, front-left 0.6, and middle-right 0.8
Tripod gait step trigger; hind-left, front-left & middle-right 0 and
hind-right, front-right & middle-left 0.5
Spiders are octapods (8 legs)
They tend to have very similar gaits to hexapods
Off-sync back to front wave gait for slow movement
Quadrapod gait (not quadruped)
Off-sync back to front wave gait step trigger; hind-left 0, front-right 0.1,
middlehind-left 0.2, middlefront-left 0.4, hind-right 0.5, front-left 0.6,
middlehind-right 0.7, and middlefront-right 0.9
Quadrapod gait step trigger: hind-left, middlehind-right, middlefront-left,
front-right 0 and hind-right, middlehind left, middlefront-right, front-left
0.5
Younger insects (larva, grubs, caterpillars) donbt tend to move around as
well as the older ones
Larva and grubs tend to wiggle & dig a lot
Caterpillars use ON-sync back to front wave gaits with each pair of left and
right legs moving together.
A caterpillar with 6 pairs of legs might have a step trigger of +0.1 per
pair of legs moving from back to front starting with 0 for the hindmost pair
and ending with 0.5 for the foremost pair.
Centipedes & millipedes tend to use off-sync back to front wave type gaits
with several waves
Some species, however use a front to back wave gait
When moving fast, their motion tends towards a tripod type gait, alternating
between two different sets of three main support zones
A very rough rule of thumb suggests 1 support zone per ~6 body segments.
Snakes
Serpentine crawling: rapid front to back waves
Sidewinding: front to back waves with strong lateral component. Often
optimized for minimal ground contact
Concertina locomotion: slower crawling front to back compressions
Worms
Stretch/squeeze: front to back squeezing/stretching waves
Also;
Climbing & Brachiation
Flying & Gliding
Swimming
Now the point of all this is in assisting with visualization of fantasy
critters or what most people call monsters.
I define a monster as an animal about which the players and local population
know next to nothing about.
A party encountering such an animal has no idea of itbs MA or the range of
itbs strikes for example.
A well designed monster can prove quite surprising in this way.
This also makes the GM actually think enough about the critter to be able to
explain more detailed questions about the animal w/o bon the flyb
descriptions that can cause issues later on in the campaign.
An example here may be the growth stages of dragons.
A 2-hex dragon that fills most of the space is about eight and a half feet
long and roughly four and a quarter feet in width, or half again as wide as
it is long.
A 4-hex dragon by the same measure is about 8.5 feet long and wide at itbs
widest point.
Is this some sort of awkward teen stage with zits and all?
If so, is there a potion use for dragon zit-juice?
I assume nobody actually b seesb a 7-hex dragon as 7 actual hexes in shape
but therein webre against the rub so to speak.
Therebs LOTbS of pictures, models, etc. of dragons.
Am I as GM picturing an oriental style of dragon thatbs more snake-like
while some players are seeing Smaug and others are thinking some movie or
what have you?
I wonbt tell a fellow GM how they must b seeb dragons, rather I ask as a
player b tell me what you seeb .
The better this visual is shared amongst all players the more creative
opportunities for play IMO.
Can a 7-hex dragon bend itbs spine in a flexible manner?
If so it might be better represented by two 4-hex dragon counters joined at
the middle, the rears head to the leadings tail like two men in a horse
costume.
Of course this makes a 14-hex dragon 13 hexesb&
So Ibm curious what the list b seesb when I ask b what does a dragon look
like?b
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