Collision Mesh

R2026b

Create convex mesh collision geometry

Since R2025a

• 

collision mesh block block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Robotics System Toolbox / Collision Detection

Description

The Collision Mesh block outputs a convex mesh collision geometry using a list of 3-D vertices relative to a pose specified in relation to the world frame.

Examples

Check Collisions Between Geometries

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

Vertices — Vertices of mesh

matrix

Vertices of the mesh, specified as an N-by-3 matrix, where N is the number of vertices and must greater than or equal to 1. Each row of Vertices represents the coordinates of a point in 3-D space. Note that some of the points can be inside the constructed convex mesh.

Pose — Pose of collision geometry

matrix

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

Output

CollGeom — Collision geometry

bus

Collision geometry, returned as a bus slCollision with these elements:

• m_Type — Type of collision geometry:

  • 0 — Collision Box

  • 1 — Collision Cylinder

  • 2 — Collision Sphere

  • 3 — Collision Capsule

  • 4 — Collision Mesh

• m_X — x-dimension size of the collision geometry in meters.

• m_Y — y-dimension size of the collision geometry in meters.

• m_Z — z-dimension size of the collision geometry in meters.

• m_Radius — Radius of the collision geometry in meters.

• m_Height — Height of the collision geometry in meters.

• m_Vertices — Vertices of the collision geometry in local frame.

• m_Position — xyz-position of the collision geometry in meters.

• m_Quaternion — Orientation of the collision geometry described as a quaternion.

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

ExitFlag — Validity of collision mesh vertices

scalar

Validity of collision mesh vertices, returned as one of these values:

• 4 — Vertices matrix contains values nonnumeric.

• 3 — Vertices matrix contains values that are not real.

• 2 — Vertices matrix contains nonfinite values.

• 1 — Vertices matrix does not have three columns.

• 0 — Vertices are valid.

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

Data Types: uint16

Parameters

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

Enable Runtime Input Dimensions Error — Validation of collision mesh vertices

on (default) | off

Select this parameter to enable runtime validation of the collision mesh vertices and return an error if Vertices is invalid.

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

Simulate using — Type of simulation to run

Code generation (default) | Interpreted execution

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

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

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"robotslcollision/Collision Mesh"

Example: add_block("robotslcollision/Collision Mesh","myModel/myBlock",MakeNameUnique="on")

More About

Configure Collision Geometry Bus

To configure the maximum number of vertices in a collision geometry block, click Configure Collision Geometry Bus in the block mask to open the Configure Collision Geometry Bus dialog box, and set the Maximum number of vertices in collision geometry parameter. The default number of vertices is 10000.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

The Collision Mesh block supports code generation with dynamic memory allocation disabled. For more information about disabling dynamic memory allocation, see Dynamic memory allocation in MATLAB functions (Simulink).

Version History

Introduced in R2025a