# Point Cloud

Point cloud geometry

Since R2021a

Libraries:
Simscape / Multibody / Curves and Surfaces

## Description

The Point Cloud block creates a set of points in space. Each point has a rigid offset with respect to the reference frame of the Point Cloud block. You can use a Point Cloud block to approximate a geometry, such as a body with concave shape, for contacts. When modeling certain sustained and distributed contact problems, the Spatial Contact Force block might perform better with a Point Cloud block than with a geometry block, such as Brick Solid or File Solid. This image demonstrates how to use a point cloud to approximate the bottom of a robot foot.

When modeling contacts for a point cloud, the Spatial Contact Force and Planar Contact Force blocks treat a point cloud as an aggregation of N-point geometries and applies contact forces to each point independently. Each contact force is based on the penetration and velocity of the individual point of the cloud.

You can create a 2-D or 3-D point cloud by using an N-by-2 or N-by-3 matrix. Each row of the matrix specifies the Cartesian coordinates of a point with respect to the reference frame of the Point Cloud block. An error occurs if the matrix has any repeated rows.

Tip

You can use the `unique` function to remove repeated rows from an input matrix.

## Ports

### Frame

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Point cloud reference frame. To specify the location and orientation of the point cloud, connect this frame to another block.

### Geometry

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Geometry frame that represents the points defined by this block. To model contacts on the points, connect this port to a Spatial Contact Force or a Planar Contact Force block.

## Parameters

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Coordinates of the points, specified as an N-by-2 or an N-by-3 matrix.

• To create a 2-D point cloud, use an N-by-2 matrix that specifies the x and y Cartesian coordinates of each point with respect to the local reference frame.

• To create a 3-D point cloud, use an N-by-3 matrix that specifies the x, y, and z Cartesian coordinates of each point with respect to the local reference frame.

When modeling contacts, use the Planar Contact Force block for 2-D point clouds and the Spatial Contact Force block for 3-D point clouds.

Data Types: `double`

### Graphic

Graphic used to visualize the point cloud. To eliminate the point cloud from the model visualization, set this parameter to `None`.

Radius of the marker for each point of the point cloud.

#### Dependencies

To enable this parameter, set Type to `Marker Cloud`.

Parameterizations for specifying visual properties. Select `Simple` to specify diffuse color and opacity. Select `Advanced` to specify more visual properties, such as Specular Color, Ambient Color, Emissive Color, and Shininess.

#### Dependencies

To enable this parameter, set Type to `Marker Cloud`.

Color of the graphic under direct white light, specified as an [R G B] or [R G B A] vector on a 0–1 scale. The optional fourth element (A) specifies the color opacity on a scale of 0–1. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set Type to `Marker Cloud`.

Graphic opacity, specified as a scalar in the range of 0 to 1. A scalar of 0 corresponds to completely transparent, and a scalar of 1 corresponds to completely opaque.

#### Dependencies

To enable this parameter, set:

1. Type to ```Marker Cloud```

2. Visual Properties to `Simple`

Color of specular highlights, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set:

1. Type to ```Marker Cloud```

2. Visual Properties to `Advanced`

Color of shadow areas in diffuse ambient light, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element (A) specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set:

1. Type to ```Marker Cloud```

2. Visual Properties to `Advanced`

Graphic color due to self illumination, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element (A) specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

#### Dependencies

To enable this parameter, set:

1. Type to ```Marker Cloud```

2. Visual Properties to `Advanced`

Sharpness of specular light reflections, specified as a scalar number on a 0–128 scale. This parameter increases the shininess value for smaller but sharper highlights. Decrease the value for larger but smoother highlights.

#### Dependencies

To enable this parameter, set:

1. Type to ```Marker Cloud```

2. Visual Properties to `Advanced`

## Version History

Introduced in R2021a