collisionCapsule

Capsule primitive collision geometry

Since R2022b

Description

The collisionCapsule object is a capsule primitive collision geometry defined by a radius and length. The central line segment of the capsule aligns with its z-axis. The origin of the body-fixed frame is at the midpoint of the central line segment of the capsule.

Creation

Syntax

CAPS = collisionCapsule(radius,length)

CAPS = collisionCapsule(___,Pose=pose)

Description

CAPS = collisionCapsule(radius,length) creates a capsule primitive with the specified radius radius and length length. The radius and length arguments set the Radius and Length properties, respectively

CAPS = collisionCapsule(___,Pose=pose) sets the Pose property of the capsule to pose, relative to the world frame.

Properties

Radius — Radius of spherical ends of capsule

nonnegative scalar

Radius of the spherical ends of the capsule, specified as a nonnegative scalar. Units are in meters.

Example: 2.5

Length — Length of central line segment of capsule

nonnegative scalar

Length of the central line segment of the capsule, specified as a nonnegative scalar. Units are in meters.

Note

This is not the length from end-to-end of the capsule. The total length of the capsule is Length+2(Radius).

Example: 4.5

Pose — Pose of capsule

eye(4) (default) | 4-by-4 matrix

Pose of the capsule relative to the world frame, specified as a 4-by-4 homogeneous transformation matrix. Units are in meters.

Example: trvec2tform([4 2 5])

Object Functions

checkCollision	Check if two geometries are in collision
convertToCollisionMesh	Convert collision primitive geometry into collision mesh geometry
genspheres	Generate spheres along central line segment of capsule
show	Show collision geometry

Examples

Generate Collision Spheres Inside Collision Capsule

Create a collision capsule with a radius of 2 and length of 10. Visualize the capsule.

cCapsule = collisionCapsule(2,10);
[~,p] = show(cCapsule);

Generate spheres at ratios 0.0, 0.5, and 1.0 of the capsule length.

spheres = genspheres(cCapsule,linspace(0,1,3));

Display the positions of the spheres.

for i = 1:length(spheres)
    disp(tform2trvec(spheres{i}.Pose))
end

     0     0    -5

     0     0     0

     0     0     5

Set the face and edge alphas of the capsule to low values. This ensures that both the spheres are visible when you add them to the figure.

p.FaceAlpha = 0.4;
p.EdgeAlpha = 0.01;
hold on

Display the generated spheres on the capsule.

cellfun(@show,spheres);

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2022b

R2023b: collisionCapsule supports specifying pose at construction

You can now specify the Pose property of collisionCapsule at object construction.

R2023a: Pose property supports se3 transformation object

You can now specify the Pose property of collisionCapsule as an se3 transformation object.