Purpose

Rigid simulates bodies that translate and rotate without deforming. Shell Sample handles sampled contacts and mechanisms; True Convex provides the OBB-SAT contact mode for box stacking. Body and constraint specifications let you author joints alongside the bodies.

Use

Place Rigid in the Geometry view, under Solvers. Connect a small point set and choose Input POP (point bodies) as Body Source. Each point supplies a body location. Start with Boxes, Body Size at 0.06, four Substeps and ten Iterations. Space the input points far enough apart for the body size.

For a joint setup, use Body + Constraint Spec or an Example Preset such as Motor Linkage or Chain. The specification accepts bodies and ball, hinge, distance and weld constraints. Start with Shell Sample for this workflow. With no authored source, Procedural Pile Count controls the fallback pile.

Inputs and outputs

The geometry input supplies point bodies or an active convex mesh, according to Body Source. Resources > Connections accepts sdf obstacles, points, velocity, contacts and a field for buoyancy.

Outputs include P, v, id, Cd and orient, plus xform transforms, contact data and a mesh output. Keep orientation when using body points downstream so the displayed bodies rotate. To try buoyancy, connect Ripple’s height field to Rigid’s field input and raise Buoyancy from its default 0.

Controls

• Contact Model changes the contact solver. Shell-specific Solve Strategy and Chebyshev controls apply to Shell Sample; the Convex controls apply to True Convex.
• Simulate pauses advancement and Reset restarts the bodies. Use Auto-Rebuild on Build Params or press Rebuild to apply pending changes to the body setup.
• Substeps and Iterations control solve effort. Body Size, Density and Friction set body scale and contact behavior. The default floor is enabled at Y = -1.5.
• Damping reduces motion. Max Velocity and Max Angular Vel cap it, while Sleep Threshold and Sleep Gate control when settled bodies sleep.
• Contact Stiffness and the joint stiffness controls tune resistance to separation or penetration. In True Convex, Restitution controls bounce and Contact Skin adds a speculative contact margin.
• Velocity Field Coupling and Buoyancy both start at 0. Set the relevant value after connecting the resource. Publish Contact Set controls outgoing contacts; Max Foreign Contacts caps incoming contact data.

Notes

Body Source, Contact Model and Body Shape are separate choices. Do not treat the active convex mesh option as arbitrary concave collision geometry.

Contact publication does not connect other solvers automatically. Add the intended Connections rows and check their Status. Start with a small body count before increasing Max Bodies or the procedural pile.

Ports

Inputs

• geometry points
• sdf sdf collider
• points points
• velocity velocity field
• contacts contacts
• field density field

Outputs

• P points
• v points
• id points
• Cd points
• orient points
• xform transforms
• contact contacts
• mesh mesh

Parameters

Rigid

Auto-Rebuild on Build Params (Autorebuild) Toggle op('rigid').par.Autorebuild

Default:

On

Options:

Off, On

Rebuild (Rebuildnow) Pulse op('rigid').par.Rebuildnow

Default:

None

Simulate (Simulate) Toggle op('rigid').par.Simulate

Default:

On

Options:

Off, On

Reset (Resetsolver) Pulse op('rigid').par.Resetsolver

Default:

None

Solver

Contact Model (Contactmodel) Menu op('rigid').par.Contactmodel

Default:

0

Options:

Shell Sample (AVBD: granular/mechanisms, full joints), True Convex (OBB-SAT: clean box stacking)

Dt (Dt) Float op('rigid').par.Dt

Default:

0.0166667

Range:

0.0001 to 0.5

Substeps (Substeps) Int op('rigid').par.Substeps

Default:

4

Range:

1 to 16

Iterations (Iterations) Int op('rigid').par.Iterations

Default:

10

Range:

1 to 64

Solve Strategy (shell) (Solvestrategy) Menu op('rigid').par.Solvestrategy

Default:

0

Options:

Colored Gauss-Seidel, Chebyshev-Jacobi (scale)

Chebyshev Rho (shell) (Chebrho) Float op('rigid').par.Chebrho

Default:

0.95

Range:

0 to 0.999

Author

Authored Scene (Hdrauthor) Str op('rigid').par.Hdrauthor

Read only.

Default:

"" (Empty String)

Body Source (Source) Menu op('rigid').par.Source

Default:

0

Options:

Input POP (point bodies), Input POP (active convex mesh), Authored Spec fallback

Example Preset (Preset) Menu op('rigid').par.Preset

Default:

0

Options:

Custom / input-authored, Motor Linkage, Chain, Ragdoll, Glue Wall (breakable)

Body + Constraint Spec (Spec) Str op('rigid').par.Spec

Default:

"" (Empty String)

Max Bodies (pool) (Maxbodies) Int op('rigid').par.Maxbodies

Default:

16384

Range:

64 to 262144

Procedural Pile Count (no source) (Procbodies) Int op('rigid').par.Procbodies

Default:

4096

Range:

1 to 2000000

Rules

Constraint Rules (Hdrrules) Str op('rigid').par.Hdrrules

Read only.

Default:

"" (Empty String)

Rigid Rule Stack (Rigidrules) Str op('rigid').par.Rigidrules

Default:

"" (Empty String)

Bodies

Body Material (input mode / spec default) (Hdrbodies) Str op('rigid').par.Hdrbodies

Read only.

Default:

"" (Empty String)

Body Shape (Bodyshape) Menu op('rigid').par.Bodyshape

Default:

0

Options:

Boxes, Spheres, Capsules, Convex Hulls

Body Size (half-extent / radius) (Bodysize) Float op('rigid').par.Bodysize

Default:

0.06

Range:

0.005 to 2

Auto-Space Bodies (no spawn overlap) (Autospace) Toggle op('rigid').par.Autospace

Default:

On

Options:

Off, On

Active Mesh Body (Hdractivemesh) Str op('rigid').par.Hdractivemesh

Read only.

Default:

"" (Empty String)

Surface Velocity Scale (Meshvelocityscale) Float op('rigid').par.Meshvelocityscale

Default:

1

Range:

0 to 10

Max Surface Velocity (Meshmaxsurfacevelocity) Float op('rigid').par.Meshmaxsurfacevelocity

Default:

20

Range:

0 to 500

Density (kg/m3) (Density) Float op('rigid').par.Density

Default:

700

Range:

1 to 100000

Friction (Friction) Float op('rigid').par.Friction

Default:

0.5

Range:

0 to 1

Contact Sample Lattice (Samplelattice) Int op('rigid').par.Samplelattice

Default:

2

Range:

2 to 5

Forces

Forces / World (Hdrforces) Str op('rigid').par.Hdrforces

Read only.

Default:

"" (Empty String)

Gravity X (Gravityx) Float op('rigid').par.Gravityx

Default:

0

Range:

-30 to 30

Gravity Y (Gravityy) Float op('rigid').par.Gravityy

Default:

-9.81

Range:

-30 to 30

Gravity Z (Gravityz) Float op('rigid').par.Gravityz

Default:

0

Range:

-30 to 30

Damping (Damping) Float op('rigid').par.Damping

Default:

0.999

Range:

0 to 1

Velocity Field Coupling (vel:) (Windcoupling) Float op('rigid').par.Windcoupling

Default:

0

Range:

0 to 1000

Floor Enabled (Floorenabled) Toggle op('rigid').par.Floorenabled

Default:

On

Options:

Off, On

Floor Y (Floory) Float op('rigid').par.Floory

Default:

-1.5

Range:

-3 to 1

Kinematic Ingest (points:) (Hdrkin) Str op('rigid').par.Hdrkin

Read only.

Default:

"" (Empty String)

Kinematic Capacity (Kinematiccap) Int op('rigid').par.Kinematiccap

Default:

0

Range:

0 to 262144

Kinematic Radius (Kinematicradius) Float op('rigid').par.Kinematicradius

Default:

0.05

Range:

0.005 to 0.5

Coupling

Coupling (Hdrcouple) Str op('rigid').par.Hdrcouple

Read only.

Default:

"" (Empty String)

Publish Contact Set (Publishcontacts) Toggle op('rigid').par.Publishcontacts

Default:

On

Options:

Off, On

Couple Weight (Coupleweight) Float op('rigid').par.Coupleweight

Default:

1

Range:

0 to 2

Max Foreign Contacts (cap) (Maxforeign) Int op('rigid').par.Maxforeign

Default:

65536

Range:

0 to 4000000

Buoyancy (field:) (Buoyancy) Float op('rigid').par.Buoyancy

Default:

0

Range:

0 to 100

Water Level Y (Waterlevel) Float op('rigid').par.Waterlevel

Default:

0

Range:

-100 to 100

Water Height Scale (Waterheightscale) Float op('rigid').par.Waterheightscale

Default:

1

Range:

0 to 100

Water Drag (Waterdrag) Float op('rigid').par.Waterdrag

Default:

2

Range:

0 to 50

Contacts

Hard Contacts (augmented Lagrangian) (Hdrhard) Str op('rigid').par.Hdrhard

Read only.

Default:

"" (Empty String)

Contact Stiffness (k0) (Contactstiffness) Float op('rigid').par.Contactstiffness

Default:

100000

Range:

1000 to 10000000

Max Velocity (Maxvelocity) Float op('rigid').par.Maxvelocity

Default:

12

Range:

0.1 to 100

Max Angular Vel (rad/s) (Maxangular) Float op('rigid').par.Maxangular

Default:

50

Range:

0.1 to 500

Contact Warmstart (Warmstart) Toggle op('rigid').par.Warmstart

Default:

On

Options:

Off, On

Warmstart Lambda Carry (Warmstartlambda) Float op('rigid').par.Warmstartlambda

Default:

0.25

Range:

0 to 1

Sleep (Hdrsleep) Str op('rigid').par.Hdrsleep

Read only.

Default:

"" (Empty String)

Sleep Threshold (vel) (Sleepthreshold) Float op('rigid').par.Sleepthreshold

Default:

0.06

Range:

0 to 2

Sleep Gate (substeps) (Sleepsubsteps) Int op('rigid').par.Sleepsubsteps

Default:

8

Range:

1 to 255

Joints (Hdrjoint) Str op('rigid').par.Hdrjoint

Read only.

Default:

"" (Empty String)

Joint Stiffness (k0 seed) (Jointstiffness) Float op('rigid').par.Jointstiffness

Default:

1000000

Range:

1000 to 10000000

Joint K Max (ramp cap) (Jointkmax) Float op('rigid').par.Jointkmax

Default:

100000000

Range:

1000 to 100000000

Convex

True-Convex Contact (sequential impulse) (Hdrconvex) Str op('rigid').par.Hdrconvex

Read only.

Default:

"" (Empty String)

Restitution (bounce) (Restitution) Float op('rigid').par.Restitution

Default:

0

Range:

0 to 1

Relaxation (SOR) (Relaxation) Float op('rigid').par.Relaxation

Default:

0.2

Range:

0.05 to 1

Baumgarte (penetration bias) (Baumgarte) Float op('rigid').par.Baumgarte

Default:

0.2

Range:

0 to 1

Penetration Slop (Penetrationslop) Float op('rigid').par.Penetrationslop

Default:

0.0015

Range:

0 to 1

Contact Skin (speculative) (Skin) Float op('rigid').par.Skin

Default:

0.01

Range:

0 to 10

Max Depenetration Vel (Maxdepenvel) Float op('rigid').par.Maxdepenvel

Default:

3

Range:

0 to 1000

SDF Speculative Band (anti-tunnel) (Sdfspecband) Float op('rigid').par.Sdfspecband

Default:

0.08

Range:

0 to 2

True-Convex Joints (Hdrcvjoint) Str op('rigid').par.Hdrcvjoint

Read only.

Default:

"" (Empty String)

Joint Iterations (Jointiterations) Int op('rigid').par.Jointiterations

Default:

8

Range:

1 to 32

Joint Baumgarte (Jointbaumgarte) Float op('rigid').par.Jointbaumgarte

Default:

0.2

Range:

0 to 1

Joint Max Correction Vel (Jointmaxcorr) Float op('rigid').par.Jointmaxcorr

Default:

2

Range:

0.01 to 1000

Color

Color Saturation (Colorsat) Float op('rigid').par.Colorsat

Default:

0.65

Range:

0 to 1

Color Value (base) (Colorval) Float op('rigid').par.Colorval

Default:

0.85

Range:

0 to 1

Color Speed Brightness (Colorspeed) Float op('rigid').par.Colorspeed

Default:

0

Range:

0 to 1

Color Speed Normalize (Colorspeedmax) Float op('rigid').par.Colorspeedmax

Default:

8

Range:

0.01 to 40

Outputs

Bodies Output Resource (Drivername) Str op('rigid').par.Drivername

Default:

rigid_drivers