Leg

assemble_leg places the femur, tibia, fibula, patella, the knee tissues and the named muscles in one connected frame. add_leg can also attach vessels, lymph, nerves, skin and hair.

extensions/humanoid/skeleton/leg/assembly.mojo stores the origin of each bone frame in the leg frame. The knee tissues and the later layers already live in that frame. See Femur, Tibia, Fibula, Patella, Knee, Muscles, Vessels, Lymph, Nerves and Integument.

This is not a three.js port. See Extensions.

Call it

from extensions.humanoid.athleticism import TONED
from extensions.humanoid.sex import MALE
from extensions.humanoid.spec import HumanoidSpec
from extensions.humanoid.skeleton.leg.assembly import assemble_leg, add_leg
from extensions.humanoid.skeleton.leg.contents import BONES, MUSCLES, BOTH
from units.si import FOOT, Length

var person = HumanoidSpec(Length(6.0, FOOT), MALE, TONED)
var pose = assemble_leg(person)
var hip = pose.hip_center()

side picks RIGHT or LEFT. A right leg is the default.

The origin is the tibiofemoral joint line. Plus y is proximal. Plus x is body-right. Plus z is anterior.

The distal femoral condyle surface sits at plus the femoral cartilage thickness. The tibial eminence sits at minus the tibial cartilage thickness. The fibular head sits just lateral and slightly distal of the tibial lateral condyle. The patella sits just anterior of the trochlea.

add_leg attaches the selected layers under a parent node. Pass contents=BONES, contents=MUSCLES or contents=BOTH. Combine layers with plus. Both is the default.

Value	Draws
BONES	Four bones and five knee tissues.
MUSCLES	The labeled muscles and three connective-tissue solids.
VESSELS	Arteries and veins.
LYMPH	Lymph nodes and trunks.
NERVES	Named peripheral nerves.
SKIN	Skin envelope.
HAIR	Thigh and calf hair shafts.
BOTH	Bones, knee tissues and muscles.
INTEGUMENT	Skin envelope and hair shafts.
ALL	Every named layer.

A bare integer is a compile error. Skin hides the inner layers when drawn with them. Use INTEGUMENT for skin and hair. Use BONES.plus(VESSELS) for a vessel gallery.

The skin layer fits cross-sections around every modeled entity. Tests require every vessel, lymphatic route and nerve station to remain below that surface.

HumanoidSpec stores stature, sex and athleticism. A two-argument spec uses untoned muscle.

Pose

LegAssembly holds each bone's dimensions, the knee dimensions, the muscle dimensions, and four origins.

Member	Meaning
femur_origin	Femur mid-shaft in the leg frame.
tibia_origin	Tibia mid-shaft in the leg frame.
fibula_origin	Fibula mid-shaft in the leg frame.
patella_origin	Patella centroid in the leg frame.
hip_center()	Femoral head.
ankle_center()	Tibial plafond.

A left leg mirrors a right leg across the body midline.

Examples

examples/leg.mojo draws one six foot male right leg and writes out/leg.png. Run it with:

.venv/bin/mojo run -I . examples/leg.mojo out/leg.png

examples/legs.mojo draws both legs. Femoral heads sit at plus and minus ten centimeters. It writes out/legs.png.

Run it with:

.venv/bin/mojo run -I . examples/legs.mojo out/legs.png

Ankle

ankle_center() returns the tibial plafond in the leg frame. That point is the origin of the foot. Pass it as origin to add_foot. See Foot.

Looks

extensions/humanoid/skeleton/look.mojo and bone.mojo hold two looks for each tissue. The Phong looks draw with any light. The physical looks are PHYSICAL materials and read best with an environment and tone mapping.

Tissue	Phong	Physical
Bone	bone_phong	bone_physical: rough, IOR 1.55
Skin	skin_phong	skin_physical: IOR 1.40, a warm sheen for scattered light
Muscle	muscle_phong	muscle_physical: a clear coat for the wet epimysium
Tendon	tendon_phong	tendon_physical: a silvery sheen along the fibers
Ligament	ligament_phong	ligament_physical
Cartilage	cartilage_phong	cartilage_physical: smooth, with a clear coat

The renderer has no subsurface scattering. The skin's sheen stands in for the soft, warm rim that scattered light gives skin.

Limb

examples/limb.mojo draws one right leg and its foot, twice, standing on a floor. The left copy has bones and muscles and no skin. The right copy is one skin over the leg and the foot, from add_limb_skin. The foot uses ankle_center() as its origin. The picture is out/limb.png.

The gallery uses the physical looks. A room environment lights it through a PMREM. A lamp casts soft shadows. ACES Filmic tone maps it.

Run it with:

.venv/bin/mojo run -I . examples/limb.mojo out/limb.png