hermes-agent/optional-skills/creative/touchdesigner-mcp/references/geometry-comp.md

Geometry COMP Reference

Creating Geometry COMPs

geo = root.create(geometryCOMP, 'geo1')
# Remove default torus
for c in list(geo.children):
    if c.valid: c.destroy()
# Build your shape inside

Correct Pattern (shapes inside geo)

# Create shape INSIDE the geo COMP
box = geo.create(boxSOP, 'cube')
box.par.sizex = 1.5; box.par.sizey = 1.5; box.par.sizez = 1.5

# For POP-based geometry (TD 099), POPs must be inside:
sph = geo.create(spherePOP, 'shape')
out1 = geo.create(outPOP, 'out1')
out1.inputConnectors[0].connect(sph.outputConnectors[0])

DO NOT: Common Mistakes

# BAD: Don't create geometry at parent level and wire into COMP
box = root.create(boxPOP, 'box1')  # ← outside geo, won't render

# BAD: Don't reference parent operators from inside COMP
choptopop1.par.chop = '../null1'  # ← hidden dependency, breaks on move

Instancing

geo.par.instancing = True
geo.par.instanceop = 'sopto1'    # relative path to CHOP/SOP with instance data
geo.par.instancetx = 'tx'
geo.par.instancety = 'ty'
geo.par.instancetz = 'tz'

Instance Attribute Names by OP Type

OP Type	Attribute Names
CHOP	Channel names: tx, ty, tz
SOP/POP	P(0), P(1), P(2) for position
DAT	Column header names from first row
TOP	r, g, b, a

Mixed Data Sources

geo.par.instanceop = 'pos_chop'       # Position from CHOP
geo.par.instancetx = 'tx'
geo.par.instancecolorop = 'color_top' # Color from TOP
geo.par.instancecolorr = 'r'

Rendering Setup

# Camera
cam = root.create(cameraCOMP, 'cam1')
cam.par.tx = 0; cam.par.ty = 0; cam.par.tz = 4

# Render TOP
render = root.create(renderTOP, 'render1')
render.par.outputresolution = 'custom'
render.par.resolutionw = 1280; render.par.resolutionh = 720
render.par.camera = cam.path
render.par.geometry = geo.path  # accepts path string

POPs vs SOPs for Rendering

In TD 099, geometryCOMP renders POPs but NOT SOPs. A boxSOP inside a geometry COMP is invisible — no errors.

# WRONG — SOPs don't render (invisible, no errors)
box = geo.create(boxSOP, 'cube')       # ✗ invisible

# CORRECT — POPs render
box = geo.create(boxPOP, 'cube')       # ✓ visible

SOP	POP	Notes
boxSOP	boxPOP	sizex/y/z, surftype
sphereSOP	spherePOP	radx/y/z, freq, type (geodesic/grid/sharedpoles/tetrahedron)
torusSOP	torusPOP	TD auto-creates in new geo COMPs
circleSOP	circlePOP
gridSOP	gridPOP
tubeSOP	tubePOP

New geometry COMPs auto-create: in1 (inPOP), out1 (outPOP), torus1 (torusPOP). Always clean before building.

Morphing Between Shapes (switchPOP)

sw = geo.create(switchPOP, 'shape_switch')
sw.par.index.expr = 'int(absTime.seconds / 3) % 4'
sw.inputConnectors[0].connect(tetra.outputConnectors[0])  # shape 0
sw.inputConnectors[1].connect(box.outputConnectors[0])    # shape 1
sw.inputConnectors[2].connect(octa.outputConnectors[0])   # shape 2
sw.inputConnectors[3].connect(sphere.outputConnectors[0]) # shape 3

out = geo.create(outPOP, 'out1')
out.inputConnectors[0].connect(sw.outputConnectors[0])

spherePOP.par.type options: geodesic, grid, sharedpoles, tetrahedron. Use tetrahedron for platonic solid polyhedra.

Misc

• connect() replaces existing connections — no need to disconnect first
• project.name returns the TOE filename, project.folder returns the directory