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Point cloud geometry for contact modeling

**Library:**Simscape / Multibody / Curves and Surfaces

The Point Cloud block exports a set of points in space for modeling contact problems. 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 solid or convex hull. When modeling sustained and distributed contact problems, the Spacial Contact Force block performs better with a Point Cloud block than with a geometry blocks, such as Brick Solid and File Solid. This image demonstrates how to use a point cloud to approximate the bottom of a robot foot.

The Point Cloud block has one reference frame port
(**R**) and one geometry port (**G**). To use a
Point Cloud block to model contact problems, connect
port **G** to a Spatial Contact Force
block. The Spatial Contact Force block treats 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. Note that the Spatial
Contact Force block does not support sensing when connected to a
Point Cloud block.

To specify the locations of points, you can enter an *N*-by-3 matrix for the **Coordinates Matrix** parameter of
the Point Cloud block. 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.