Collision Sphere

Create sphere collision geometry

Since R2025a

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  • Collision Sphere block

Libraries:
Robotics System Toolbox / Collision Detection

Description

The Collision Sphere block outputs a sphere collision geometry with the origin of the geometry-fixed frame at the center of the sphere.

Examples

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Open Live Script

Open the Simulink® model. This model contains all five of the collision geometry blocks in the Collision Detection library and checks for collision between any two of the collision geometries. Note that the Collision Mesh block uses vertices from the exampleMeshVertices MAT file. The model loads the exampleMeshVertices MAT file when you open the model by using the PreLoadFcn callback. 

model = "CollisionCheckingBetweenGeometries.slx";
open_system(model)

Simulate the model.

out = sim("CollisionCheckingBetweenGeometries.slx")
out = 
  Simulink.SimulationOutput:

             collStatus: [1x1 timeseries] 
               geom1Idx: [1x1 timeseries] 
               geom2Idx: [1x1 timeseries] 
                logsout: [1x1 Simulink.SimulationData.Dataset] 
                sepDist: [1x1 timeseries] 
                   tout: [101x1 double] 
             witnessPts: [1x1 timeseries] 

     SimulationMetadata: [1x1 Simulink.SimulationMetadata] 
           ErrorMessage: [0x0 char]

Get data from the simulation output.

collCheckingPairs = [out.geom1Idx.Data out.geom2Idx.Data];
collStatuses = out.collStatus.Data;
sepDistances = out.sepDist.Data;
witnessPoints = out.witnessPts.Data;

Ports

Input

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Radius of the sphere, specified as a positive scalar. Units are in meters.

Pose of the collision geometry relative to the world frame, specified as a 4-by-4 homogeneous matrix.

Output

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Collision geometry, returned as a bus.

To perform collision checking, connect this output to a Check Collision block as input.

Validity of collision sphere radius, returned as an integer scalar:

  • 4 — Specified dimension value is not numeric.

  • 3 — Specified dimension value is not a real number.

  • 2 — Specified dimension value is nonfinite.

  • 1 — Specified dimension value is not positive.

  • 0 — Specified dimension value is valid.

To validate the radius at runtime instead, select the Enable Runtime Input Dimensions Error parameter.

Data Types: uint16

Parameters

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To edit block parameters interactively, use the Property Inspector. From the Simulink® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Select this parameter to enable runtime validation of the collision sphere dimensions and error during simulation if Radius is invalid.

If you clear this parameter, the block does not error during simulation, and instead uses the ExitFlag port to identify if the radius is invalid.

  • Interpreted execution — Simulate model using the MATLAB® interpreter. For more information, see Interpreted Execution vs. Code Generation (Simulink).

  • Code generation — Simulate model using generated C code. The first time you run a simulation, Simulink generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change.

Tunable: No

More About

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Extended Capabilities

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Version History

Introduced in R2025a

See Also

Objects

Blocks