Pulga Physics Solver

Functionality

This node creates simulations from input parameters, it is meant to be used in form-finding purposes. It creates the simulation using the inputted vertices as spherical particles that react to applied forces.

The node is a basic NumPy implementation of basic physics system heavily inspired in “The Nature of Code” by Daniel Shiffman and the Kangoroo Plug-in for Grasshopper. Due the nature of the algorithm it can get very intensive, handle with responsibility

Input & Output

Input	Type	Description
Initial_Pos	Vertices	Vertices in original state
Iterations	Integer	Number of iterations of the process
Radius	Float	Radius of virtual sphere, used to calculate intersections, mass and surface
Initial Velocity	Vertices	Initial vertices velocity
Max Velocity	Float	Maximum vertices velocity
Density	Float	Particles Density
Forces	Force	System forces

Output	Type	Description
Vertices	Vertices	Vertices in original state
Radius	Strings	Radius of virtual sphere, used to calculate intersections, mass and surface
Velocity	Vertices	Velocity at the end of iterations
Pin Reactions | Strings		Reactions at Pinned Vertices

Accumulative:

When activated every nodeTree update will use the previous update as the starting point. The update can be triggered by the Update button or by any other event that triggers regular updates (like playing animation or changing any value).

It offers some options:

Reset: Takes back the system to the initial state.

Update: Runs one Node-Tree update.

Pause: Pauses nodes calculations and ignores ui changes.

Examples

Arranging circles with attraction and collision.

• Generator-> Plane

• Transform-> Randomize

• Number-> Random Num Gen

• List->List Main-> List Join

• Generator-> Circle

• Viz-> Viewer Draw

• Pulga Physics-> Pulga Drag Force

• Pulga Physics-> Pulga Collision Force

• Pulga Physics-> Pulga Attraction Force

• Pulga Physics-> Pulga Fit Force

• Pulga Physics-> Pulga Boundaries Force

Getting result in animation:

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Inflating a cube simulating a pillow.

• Generator-> Box

• Viz-> Viewer Draw

• Pulga Physics-> Pulga Springs Force

• Pulga Physics-> Pulga Drag Force

• Pulga Physics-> Pulga Inflate Force

Animated:

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Tensile structures can be studied with pinned points.

• Generator-> Line

• Generator-> 3pt Arc

• Generator->Generator Extended-> Polygon Grid

• Analyzers-> Path Length

• Transform-> Transform Select

• Modifiers->Modifier Make-> Subdivide

• Number-> List Input

• MUL X, SIN, DIV: Number-> Scalar Math

• Vector-> Vector Out

• Vector-> Vector Rewire

• ANGLE RAD: Vector-> Vector Math

• Matrix-> Matrix In

• List-> List Mask (Out)

• List->List Main-> List Join

• List->List Struct-> List Item

• Modifiers->Modifier Make-> UV Connection

• Modifiers->Modifier Make-> Solidify

• Pulga Physics-> Pulga Springs Force

• Pulga Physics-> Pulga Drag Force

• Pulga Physics-> Pulga Pin Force

Animated:

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Using the caternary as a structural modeling tool:

• Generator-> Line

• Generator-> Circle

• Number-> A Number

• Number-> Scalar Math

• Number-> Number Range

• Number-> Float to Integer

• List->List Main-> List Join

• List->List Main-> List Join

• List->List Struct-> List Item

• Viz-> Polyline Viewer

• Pulga Physics-> Pulga Vector Force

• Pulga Physics-> Pulga Springs Force

• Pulga Physics-> Pulga Drag Force

• Pulga Physics-> Pulga Pin Force

Animated:

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Variable spring stiffness can be used to simulate sewing springs inflatable structures.

• Generator-> Circle

• Generator-> Box

• Generator-> Torus

• Analyzers-> Points Inside Mesh

• Number-> List Input

• Matrix-> Matrix In

• Matrix-> Matrix Apply to Mesh

• Matrix-> Matrix Normal

• List-> Mask Converter

• List->List Struct-> List Item

• Viz-> Viewer Draw

• Pulga Physics-> Pulga Springs Force

• Pulga Physics-> Pulga Inflate Force

• Pulga Physics-> Pulga Drag Force

• List->List Main-> List Join

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Shooting particles to a attractors field.

• Generator-> Circle

• Generator->Generator Extended-> Polygon Grid

• Modifiers->Modifier Make-> UV Connection

• Number-> A Number

• Number-> Number Range

• Number-> Random Num Gen

• Vector-> Vector In

• Vector-> Vector Polar Input

• List->List Struct-> List Repeater

• Viz-> Viewer Draw

• Pulga Physics-> Pulga Attractors Force

Animated:

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The “Pins Reactions” output supply the resultant force on the pins. It can be use to model auxiliary structures.

• Generator-> Line

• Generator-> Plane

• Analyzers->Component Analyzer Adjacent Edges: Adjacent edges

• EQUAL: Logic-> Logic Functions

• List-> Mask To Index

• List-> List Mask (Out)

• List->List Main-> List Join

• Viz-> Viewer Draw

• Pulga Physics-> Pulga Vector Force

• Pulga Physics-> Pulga Springs Force

• Pulga Physics-> Pulga Pin Force

Animated