expression

Connects multiple plugs using a custom mathematical expression.

This modifier allows for advanced control by combining plug values through expressions, offering greater flexibility than standard math operators.

It is the preferred way to perform complex logic or vector operations in Mikan.

Options

• op (str): The expression string.
• <[a-z0-9]> (plug): Plug references used as variables within the expression.

Syntax

• Assignments use =
• Math operators: +, -, *, /, ^ (power), % (modulo), parentheses ()
• Logical operators: | (or), & (and), ! (not)
• Booleans: true, false, or aliases on, off
• Constants: e, pi
• Vectors: [x, y, z]
  • Access components using .x, .y, .z
• Keywords:
  • frame, time: Current frame number
  • flip: Equals 1 by default, -1 for mirrored branches

Conditional expressions

Use the ternary syntax:

condition ? true_value : false_value

You can nest conditions with parentheses:

cond1 ? (cond2 ? val2 : val3) : val1

Works with scalars and vectors alike.

Available Functions

Scalar functions

Function	Description
inverse(x)	1 / x
exp(x)	e^x
sqrt(x)	Square root
clamp(v, min, max)	Limits value within bounds
remap(v, min1, max1, min2, max2)	Remaps value from one range to another
lerp(v1, v2, w)	Linear interpolation between v1 and v2
abs(v)	Absolute value
sign(v)	Returns 1, 0 or -1
min(a, b) / max(a, b)	Min/Max between two values
cos(a), sin(a), tan(a)	Trigonometric functions
acos(v), asin(v), atan(v)	Inverse trig functions
noise(v)	Noise (simplex in Tang, Perlin in Maya)
dnoise(v)	Directional noise [-1, 1]
switch(v, a, b, c...)	Enum-style value selection
int(v) / bool(v)	Type conversion
value(v)	Gets value at build time (won’t update at runtime)

Vector functions

Function	Description
len(v)	Vector length
distance(v1, v2)	Distance between two points
angle(v1, v2)	Angle in degrees between two vectors
norm(v)	Normalized vector
dot(v1, v2)	Dot product
cross(v1, v2)	Cross product
lerp(v1, v2, w)	Linear interpolation between vectors

Examples

Squash & Stretch interpolation:

expression:
  op: y = lerp(x, 1/sqrt(x), f)
  y: driven::roots.0@s.x
  x: driver::skin.0@s.y
  f: driver::ctrls.0@squash

Using quaternions in expressions:

expression:
  op: psd = quat([rx, ry, rz], xyz).z
  psd: arm.L::j.clavicle@qz
  rx: arm.L::j.clavicle@r.x
  ry: arm.L::j.clavicle@r.y
  rz: arm.L::j.clavicle@r.z