Adding a Formula node

The Formula node allows you to create a formula that can be applied to several nodes at the same time. For example, you create a Formula node and define two outputs - Width and Height - and link them to several generators. When you modify the formula, all linked generators use the new sizes, for example 2048 instead of 1024.

This node can have 0 to 10 input connectors and 1 and 10 output connectors. Both the input and output connector formula results are numbers.

To add a Formula node, right click in the Graph Editor and select Create Node  > Calculation  > Formula.

Double click on the node to open its parameters:



Editing a Formula node

The parameters window allows you to add connectors and define formulas.

  • Click Add input to add an input connector. Click again to add another, and so on. 0 to 10 input connectors are permitted.

The input connectors must link to other calculation nodes

  • Click in the Input text field to change the input connector name.
  • Delete an input connector by clicking on .
  • Click in the Output text field to change the output connector name.
  • Click Add output to add an output connector. Click again to add another, and so on. 1 to 10 output connectors are permitted.
  • For each output, write a formula that represents the value of the output connector. A formula can be a simple number.


  • Delete an output connector by clicking on .

When a node is linked to the Formula node, the corresponding value in the node's properties is no longer editable. For example, if the Formula node is linked to the Coefficient of the first terrain, this parameter is grayed out in the Composition node's parameters.

Example

In the example below, the Equations formula node has two input connectors, X and Y, which take the values 400 and 150 defined by the X and Y formula nodes.

The Equations node output connectors use these X and Y values in two formulas to define the width and height of two Perlin noise generators.

The Width and Height parameters of both Perlin noise node parameters are non-editable because they are defined by the formula.

The generators are combined using a Max node, where the value of the output terrain is the maximum value of both input terrains. Here is the result:

Formula node compatibility

Fully compatible nodes

Terrain generation Terrain composition Mask generation
Perlin noise Sum Mask from heights
Billowy noise Difference Mask from slopes
Ridged noise Average Mask from curvature
Slope Min Mask from higher terrain
Half-sphere Max Disk
Terrain transformation Composition Painted mask
Apply curve Sum using mask Mask transformation
Color management Difference using mask Invert
Apply color ramp Average using mask Reduce
Apply color map Alpha blend Scale & offset
Extract color map Composition using mask Apply curve
Calculation Export Mask composition
Formula Mask Sum
All Import nodes Mesh Difference
  Color map Average
  Min
    Max
    Composition

Partially compatible nodes (for terrain width, height, and quad size)

Terrain generation Terrain composition Mask composition
Cone Full composition Full composition
Circular symmetry Full composition using mask  
Profile curve    
Mandelbrot set    

Incompatible nodes

Terrain transformation Mask transformation Simulation
Change terrain size Change size Hydraulic erosion
Smooth Smooth Color
Scale & offset Transform mask Create color ramp
Min & max heights Export  
Transform terrain Terrain  
     

Parameters

Parameter Use
Add input Adds an input connector
Input name box Text field to enter the input name
Output formula box Text field to enter the output formula
Output name box Text field to enter the output name
Add output Adds an output connector

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