Digital Art Week
To avoid misunderstandings: My 3D coordinates widget runs as follows:
X-Axis from left to right. Movement around this axis will be called BEND (as if you bend your knee).
Y Axis from top to bottom. Movement around this axis will be called TWIST (like the dance).
Z Axis from front to back. Movement around this axis will be called TURN (as in turning your hand upside down).
General tips on posing
Remember that even fantasy creatures and aliens should have a skeleton, tendons and muscles (or anything else that supports, connects and moves their body). If you have a creature whose design is unusual or even new, try to imagine how it could work. Let yourself be guided by creatures similar to yours
, or at least body parts of creatures similar to those of the creature you want to pose. Dragons are a mix of lizards and bats. Hydrae are a mix of snakes and dinosaurs. Griffons are a mix of birds and lions (who would have guessed…). Find an animal with a body part you need and take a look at its bone structure and muscles.
Main nodes differing from humanoid figures
Arms / Wings
[Source: Wikipedia, public domain]
Every arm on our planet consists of the same main bones: shoulder blade (scapula), upper arm (humerus) and forearm (radius and ulna). The bones of the hand and wrist may vary due to merging, but normally, we have a lot of bones in the wrist, the carpals in the palm and the fingers with three phalanges each. It doesn’t matter if the arm is of a human (lower row, rightmost arm) or of a platypus, mouse, horse, bird or whale.
Wings are nothing more than arms. Look at the picture above: in the upper row the one on the right is a bird’s arm, in the lower row the one on the left is a bat’s arm. Those are the main two wing styles you’ll find.
[Source: Wikipedia, public domain]
These images tell two main facts. First, there are no muscles to move single feathers, but everything’s done by bending, twisting and turning the wing and physical influence like pressure and air resistance. Second, there are some flying membranes, called ‘patagium’. One is located between elbow and chest (the Metapatagium or rear flying membrane) and one between shoulder and wrist (the Propatagium or anterior flying membrane). Both stabilize the wing. If you come from digital painting or model your creatures yourself, don’t forget those; bat’s wings do have them, too.
But the first fact is more important for posing in 3D. If your model comes with according morphs, don’t forget to bend the feathers to the pressure! If it doesn’t, use whatever manipulation tools your software has. When they don’t curve, the wing looks stiff. A wing functions by a slight overpressure beneath and a high negative pressure above the wing to keep anything airborne. Thus, the feathers (and wing membranes of bat wings) are cupped when the wing flaps downwards or is used for gliding. In contrast, the feathers will stretch outwards and upwards to give way to the air (and the feathers will turn, but that will in most cases not be possible to pose, except when really all feathers are single nodes).
Bat wings are slightly different from bird’s wings, because the main wing membranes sit between the fingers. Thus, the single membranes curve with the air pressure as the whole bird wing does. Plus, since bat wings can’t just turn the feathers to make space for the air, the flying cycle differs from a bird’s. While birds can flap their wings nearly straight up and down (although it looks more of an oval in slow motion captures), a bat has to bend the whole wing to “release” the air below what causes a more circular movement of the wing. Take a look at slow motion videos if you plan an animation.
What’s true for arms and wings is true for legs. It always consists of the same bones: thigh (femur), shin (tibia) and calf (fibula), the ankle bones (tarsals), mid-foot bones (metatarsals) and toes (phalanges).
There are three types of walking: on the whole sole (plantigrade), only on the toes (digitigrade) and only on the toe tips (unguligrade). For every type, the skeleton is slightly different. Humans, apes and bears are sole walkers. Cats, dogs and birds are toe walkers. Their metatarsals are elongated and they can run and jump well. Toe-tip walkers are horses, ruminants and (as a subcategory ‘semi-unguligrade') other hoof-bearing animals, plus the elephant, the hippopotamus and the rhino. Here, the foot has become pillarlike; the metacarpals have merged, as often have the fingers to build up the stability for walking.
But what about four-legged creatures? Is the front extremity an arm or a leg? It’s an arm. You can see it in this drawing of a tiger’s skeleton:
The difference between an arm and a leg is mainly the direction in which the first joint after the hip/scapula bends
: the elbow bends back (the forearm comes forward), the knee bends forward (the shin goes to the back). I tried to do two animations, but I’m not much of an animator, so don’t hit me for the mistakes.
Tail / Long Neck / Tentacle
There is not much to say about those – just please remember that (except for a tentacle) there are bones in a neck or tail that have a maximum angle that they can bend, twist or turn. Neither can a snake just “kink” to a side, nor can a giraffe kiss its own neck. There are vertebrae that prohibit too extreme movement. A tentacle, on the other hand, consists of muscle only and can do more extreme stuff.
Please bear in mind that a four-legged creature running also bends its spine. A normal trot will turn the spine while the legs are moved criss-cross (except for camels or dromedars, who move in amble), but it bends the spine only a little. A gallop/run still moves the legs criss-cross, but it uses the spine for gaining ground, too, combining a jump with a walk: the hind legs hit the ground almost simultaneously (yet in front of each other), the hip arches forwards, while the last front leg leaves the ground, and the chest ever so slightly arches forwards, too. Yep, a tiny moment of flight here, every extremity in the air before the hind legs touch down. Now the front legs reach out, the chest bends back again, the hind legs are the weight-carriers and move backwards, the hip bending back. When the first front leg has touched the ground and is the “standing” leg for a moment, the back is arched backwards – the hind legs have given their momentum and are stretched out backwards, and the other front leg is stretched out forward to gain some more ground. When the second front leg is the standing leg moving backwards, the hind legs come forward, bending the hip to the front again, and the other front leg leaves the ground. Now we are where we started, and the cycle starts over.
To boil it down after this confusing description of something you’d better look at animated (so go out there and search for “dog running” or “horse gallop”): The running cycle has two main stages, the stretch and the contraction phase.
In the stretch phase, the legs are stretched out to gain space – the hind legs give their momentum, the front legs reach out. In this phase, the spine is arched backwards. If you want to do this pose, try reaching something just above your head.
The contraction phase is the opposite: the front legs have given their momentum, and the hind legs come forward to gain ground. In this phase, the spine is curled up. If you want to do it, bring your elbows to your knees.
Or you watch a caterpillar walking. Redo with the spine.