The 'op' and 'me' Objects

op and me are the two Python names you’ll type more than any others in TouchDesigner. Both are auto-imported, so you never need to import the td module to use them.

op() : Find Any Operator

op() is a function that returns an OP object given a path or a name. The path can be absolute (rooted at /) or relative to the calling op.

Form	Resolves to
op('noise1')	A sibling in the same network as the calling op
op('./noise1')	Same as above, made explicit
op('../noise1')	A sibling of the parent (one level up)
op('/project1/geo1/noise1')	Absolute path from project root
op('noise*')	Returns the first match for the wildcard pattern
ops('noise*')	Returns every match as a list
opex('noise1')	Same as op() but raises an exception if not found

op() returns None when the path doesn’t resolve. Use opex() if you’d rather get an exception (helpful inside scripts where a typo should fail loudly).

n = op('noise1')
if n:
    print(n.par.amp.eval())

Global OP Shortcuts (op.NAME)

You can give a COMP a Global OP Shortcut name (RMB → Common page → Global OP Shortcut). Once set, that COMP becomes reachable from anywhere in the project as op.YourName, no matter where it lives in the hierarchy.

op.PROJECT          # the COMP whose Global OP Shortcut is "PROJECT"
op.PROJECT.par.tx

This is the preferred way to reference top-level singletons (your audio engine, your settings COMP, your render output).

me : The Current Operator

me is whatever operator is currently running the code. In a parameter expression, me is the operator that owns the parameter. In a Text DAT script, me is the DAT itself. In an Extension method, me is the COMP the extension is attached to.

Common access	Returns
me.name	The operator’s name as a string
me.path	Full path string
me.par.tx	A parameter on the current op
me.par.tx.eval()	Evaluated value of that parameter
me.parent()	The parent COMP (no integer means level 1)
me.inputs	List of upstream connected ops
me.children	List of contained ops (only meaningful on a COMP)
me.digits	Trailing digits in the name ('noise17' → 17)

The me.digits attribute is useful when you replicate a node and want each copy to behave slightly differently:

# Inside an expression on a Constant CHOP, replicated as constant1, constant2, ...
me.digits * 0.1

parent() and Parent Shortcuts

parent() walks up the component hierarchy.

Form	Resolves to
parent() or parent(1)	The immediate parent COMP
parent(2)	Grandparent
parent.MyName	The nearest ancestor that has a Parent Shortcut named MyName

Counting parents with parent(2) is brittle: the moment you nest your COMP one level deeper, every expression breaks. Parent Shortcuts solve that.

To set a Parent Shortcut, open the COMP’s parameters → Common page → Parent Shortcut field, type a name like Effect. Now from anywhere inside that COMP or any descendant, parent.Effect always resolves to it.

parent.Effect.par.Speed = 0.5     # set the wrapper's Speed param
parent.Effect.path                # absolute path to the wrapper

By default /project1 ships with the Parent Shortcut Project, so parent.Project works from anywhere as the project-root reference.

iop and ipar : Internal Shortcuts

When building a reusable component, you’ll often want to give the outside world a clean name for some internal op or parameter. Two more auto-imported helpers:

• iop : Internal Operator Shortcut. Defined on a COMP’s Common page. From inside the COMP, iop.Audio resolves to the named internal op.
• ipar : Internal Parameter Shortcut. Same idea but pointing at a specific parameter.

These keep your inner network refactorable without breaking expressions written elsewhere inside the COMP.

Common Gotchas

me in a non-cooking script. In a callback DAT script (onCook, onValueChange), me is the DAT containing the callback, not the op being watched. Use the function arguments (often called dat, chop, par) for the watched op.

Passing me vs evaluating it. me.par.tx is a Par object reference. me.par.tx.eval() is the current numeric value. In an expression, both work because the result is auto-cast, but in a script you usually want the explicit .eval().

Wildcard surprise. op('noise*') returns just the first match. To get all matches, use ops('noise*').

What’s Next

• Python in TouchDesigner
• Custom Parameters

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