Graph Parameters¶

Graph Parameters are reusable controls that can drive multiple nodes in your network. They're the foundation of parametric, data-driven modeling in Nodo.

What are Graph Parameters?¶

Graph Parameters let you:

• Define once, use everywhere - Create a parameter that controls multiple nodes
• Build intelligent models - Make your procedural systems respond to high-level controls
• Create presets - Save different parameter sets for quick iterations
• Share controls - Let one slider affect many operations

Think of them as "master controls" for your node graph.

Creating Graph Parameters¶

Using the Graph Parameters Panel¶

1. Open Graph Parameters panel (View → Panels → Graph Parameters)
2. Click the "+" button (Add Parameter) in the toolbar
3. Enter parameter details:
4. Name: Unique identifier (e.g., base_radius, tower_height)
5. Type: Float, Int, Bool, String, or Vector3
6. Default Value: Initial value
7. Range (for numeric types): Min and max values
8. Click OK

The parameter now appears in the Graph Parameters panel and can be referenced in expressions.

Using Graph Parameters¶

Referencing in Expressions¶

Once created, reference graph parameters in any expression:

$param_name

Or using the full path:

ch("/graph/param_name")

Example: Controlled Scale¶

Setup: 1. Create graph parameter: scale_factor (Float, default 1.0) 2. Add a Sphere node 3. Set Sphere's radius expression: $scale_factor 4. Add a Box node 5. Set Box's size_x expression: $scale_factor * 2

Now one slider controls both shapes!

Graph Parameter Types¶

Float¶

Decimal numbers with optional range.

Properties: - Default value - Min/Max range - UI widget: Slider or number field

Example:

Name: detail_level
Type: Float
Default: 1.0
Range: 0.1 to 5.0

Usage:

ch("/graph/detail_level") * 32  # Scale segments based on detail

Int¶

Whole numbers.

Properties: - Default value - Min/Max range - UI widget: Number field or slider

Example:

Name: copy_count
Type: Int
Default: 6
Range: 1 to 100

Usage:

$copy_count  # Direct use in Array count

Bool¶

True/false toggle.

Properties: - Default value (on/off) - UI widget: Checkbox

Example:

Name: enable_detail
Type: Bool
Default: true

Usage:

$enable_detail ? 64 : 16  # Conditional segments

String¶

Text values.

Properties: - Default text - UI widget: Text field

Example:

Name: export_prefix
Type: String
Default: "model"

Usage:

$export_prefix + "_v01.obj"  # Build file paths

Vector (Vec3)¶

Three float values (X, Y, Z).

Properties: - Default X, Y, Z - Optional range per component - UI widget: Three number fields

Example:

Name: global_offset
Type: Vec3
Default: (0, 0, 0)

Usage:

ch("/graph/global_offset.x")  # Access X component
ch("/graph/global_offset.y")  # Access Y component

Expression Examples¶

Simple Reference¶

$radius  # Use graph parameter directly

Math with Parameters¶

$base_size * 2.5  # Scale up
sin($angle) * $amplitude  # Trigonometry

Combining Multiple Parameters¶

$width * $height * $depth  # Volume calculation
min($max_size, $input_value)  # Clamping

Conditional Logic¶

$enable_feature ? $detail_high : $detail_low

Vector Components¶

ch("/graph/offset.x") + 10  # Offset X by 10
length(ch("/graph/position"))  # Vector magnitude

Common Workflows¶

Master Scale Control¶

Create a single scale parameter that affects everything:

1. Graph parameter: master_scale (Float, default 1.0)
2. All size-related parameters use: base_value * $master_scale

Example: - Sphere radius: 1.0 * $master_scale - Box size: 2.0 * $master_scale - Array spacing: 3.0 * $master_scale

Detail Level System¶

Control model complexity with one slider:

1. Graph parameter: detail (Float, 0.0 to 1.0)
2. Use for subdivision, segments, etc.

Example:

segments = int(8 + $detail * 56)  # 8 to 64 segments
subdivisions = floor($detail * 3)  # 0 to 3 subdivisions

Feature Toggles¶

Enable/disable parts of your model:

1. Graph parameter: include_details (Bool, default true)
2. Use in Switch nodes or conditionals

Example:

$include_details ? 1 : 0  # Switch node input selection

Export Variants¶

Drive multiple export configurations:

1. Graph parameters: lod_level (Int), export_name (String)
2. Use in Export node paths and settings

Best Practices¶

Naming Conventions¶

Organize Parameters¶

Group by purpose: - Global: master_scale, detail_level - Dimensions: width, height, depth - Features: enable_windows, enable_roof - Export: export_format, export_quality

Set Sensible Ranges¶

Example:

height: 0.1 to 100.0  # Building height in meters
segments: 3 to 128    # Geometry detail

Document Your Parameters¶

Use descriptions to explain what each parameter controls:

Name: wall_thickness
Type: Float
Range: 0.05 to 2.0
Description: "Thickness of outer walls in meters"

Advanced Techniques¶

Derived Parameters¶

Create parameters that calculate from others:

# Graph parameter: base_radius
# Another node uses:
diameter = $base_radius * 2
circumference = $base_radius * 2 * pi

Ratio-Based Design¶

Lock proportions using ratios:

# Graph parameter: base_width
height = $base_width * 1.618  # Golden ratio
depth = $base_width * 0.5     # Half width

Responsive Systems¶

Make geometry adapt to changes:

# More copies = smaller size (maintain total coverage)
copy_size = $total_size / $copy_count

Multi-Stage Control¶

Chain parameters through multiple nodes:

1. Graph param: complexity (0-1)
2. Node A: segments = 8 + $complexity * 56
3. Node B: subdivisions = floor($complexity * 3)
4. Node C: scatter_count = int(100 + $complexity * 900)

Graph Parameters Panel¶

Panel Features¶

• Add Parameter - Create new graph parameter
• Edit Parameter - Change name, type, range, default
• Delete Parameter - Remove unused parameters
• Reorder - Drag to organize

Editing Parameters¶

Click a parameter to edit: - Name - Identifier used in expressions - Label - Display name in UI - Type - Float, Int, Bool, String, Vec3 - Default - Initial value - Range - Min/max bounds (for numeric types) - Description - Tooltip help text

Troubleshooting¶

"Parameter not found" error¶

Cause: Parameter name misspelled or doesn't exist.

Fix: - Check spelling: $radius vs $raduis - Verify parameter exists in Graph Parameters panel - Use exact name (case-sensitive)

Expression doesn't update¶

Cause: Parameter reference is wrong, or expression is cached.

Fix: - Click parameter to refresh - Check expression syntax - Try re-entering the expression

Parameter has no effect¶

Cause: No nodes are using the parameter.

Fix: - Reference it in node parameter expressions: $param_name - Verify expressions are in Expression Mode (blue)

Can't delete graph parameter¶

Cause: Parameter is still referenced by nodes.

Fix: - Find all references (future: show usage count) - Remove references first - Then delete the parameter

Examples¶

Architectural Column¶

Create a parametric column:

Graph Parameters:

height: 3.0 (Float, 0.5 to 20.0)
radius: 0.3 (Float, 0.1 to 2.0)
flutes: 12 (Int, 4 to 32)

Node Setup: 1. Cylinder (height: $height, radius: $radius) 2. Array Radial (count: $flutes) 3. Boolean Subtract (create fluting)

Procedural Building¶

Graph Parameters:

floors: 5 (Int, 1 to 50)
floor_height: 3.0 (Float, 2.5 to 5.0)
width: 10.0 (Float, 5.0 to 50.0)

Expressions:

building_height = $floors * $floor_height
window_spacing = $floor_height * 0.8

Export Variants¶

Graph Parameters:

lod: 1 (Int, 0 to 3)  # Level of detail
export_name: "asset" (String)

Expressions:

segments = 8 * pow(2, $lod)  # 8, 16, 32, 64
filename = $export_name + "_lod" + str($lod) + ".obj"

See Also¶

• Expression Syntax - Full expression language reference
• Math Functions - Available functions
• Channel References - Using ch() to reference parameters

Next Steps: Learn the Expression Syntax to unlock the full power of graph parameters.