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Collision-checking options between 3-D occupancy map and collision geometries

Since R2022b


    The occupancyMap3DCollisionOptions object contains options for checking for collisions using the checkMapCollision function, between occupied cells of an occupancyMap3D object and collision geometry objects.



    OPTS = occupancyMap3DCollisionOptions returns a collision-checking options object,OPTS.


    OPTS = occupancyMap3DCollisionOptions(Name=Value) specifies properties using one or more name-value arguments. For example, occupancyMap3DCollisionOptions(SearchDepth=8) sets the SearchDepth property of the occupancyMap3DCollisionOptions object to a depth of 8.


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    Check collisions between AABBs of voxels and geometries, specified as a logical 1 (true) or 0 (false).

    If the CheckNarrowPhase property is true, the narrow phase checks only the voxels that failed the broad phase check.

    Example: occupancyMap3DCollisionOptions(CheckBroadPhase=false)

    Data Types: logical

    Check collisions between voxels and raw input geometries, specified as a logical 1 (true) or 0 (false).

    If the CheckBroadPhase property is true, the narrow phase checks only the voxels that were in collision during the broad phase check.

    Example: occupancyMap3DCollisionOptions(CheckNarrowPhase=false)

    Data Types: logical

    Exhaustive search mode, specified as a logical 0 (false) or 1 (true). When Exhaustive is specified as false, the collision-checking function stops collision checking on the first valid collision in either the broad phase or narrow phase. When specified as true, the collision-checking function continues collision checking until all voxels are checked.

    Example: occupancyMap3DCollisionOptions(Exhaustive=true)

    Data Types: logical

    Return the closest point and distance, specified as a logical 0 (false) or 1 (true). When specified as true, the collision-checking function returns the minimum distance between collision geometries and the nearest voxels in the occupancy grid.

    Example: occupancyMap3DCollisionOptions(ReturnDistance=true)

    Data Types: logical

    Return the location and size of the voxels in collision, specified as a logical 0 (false) or 1 (true).

    Example: occupancyMap3DCollisionOptions(ReturnVoxels=true)

    Data Types: logical

    Maximum search depth to check in the octree, specified as an integer in the range [0, 16].

    If a voxel at one search depth encompasses any voxel that is occupied at a greater search depth, then the entire volume of the encompassing voxel is considered occupied. For more information, see Visualize 3-D Occupancy Maps with Varying Search Depths.

    Example: occupancyMap3DCollisionOptions(SearchDepth=8)

    Data Types: uint8


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    Create a 3-D occupancy map.

    map = occupancyMap3D;

    Specify 25 random coordinates in the occupancy map as occupied.

    pt = (rand(25,3)-.5)*20;

    Create a collision sphere and a collision cylinder object.

    sphere = collisionSphere(1);
    cylinder = collisionCylinder(3,6);
    sphere.Pose = trvec2tform([6.1 -4 -7.5]);

    Visualize the occupancy map and collision geometry in the same figure.


    Perform only the broad-phase collision check for both the sphere and cylinder by setting the CheckNarrowPhase property of an occupancyMap3DCollisionOptions object to false. Return voxel information and the distance to the nearest occupied voxels.

    bpOpts = occupancyMap3DCollisionOptions(CheckNarrowPhase=false,ReturnDistance=true,ReturnVoxels=true);
    [bpIsCollidingCylinder,bpResultsCylinder] = checkMapCollision(map,cylinder,bpOpts);

    Check the voxel distances for the collision geometries. Note that, because the cylinder is in collision with voxels, the distance values are NaN. Because the sphere is not in collision with any voxels, its distance results are non-NaN values.

    bpDistCylinder = bpResultsCylinder.DistanceInfo.Distance
    bpDistCylinder = NaN
    bpWitnessptsCylinder = bpResultsCylinder.DistanceInfo.WitnessPoints
    bpWitnessptsCylinder = 3×2
       NaN   NaN
       NaN   NaN
       NaN   NaN

    Because the cylinder is in collision with the voxels, the distance results contain NaN values. Since the sphere is not in collision with the voxels, the distance results consist of non-NaN values.

    [bpIsCollidingSphere,bpResultsSphere] = checkMapCollision(map,sphere,bpOpts);
    bpDistSphere = bpResultsSphere.DistanceInfo.Distance
    bpDistSphere = 2.3259
    bpWitnessptsSphere = bpResultsSphere.DistanceInfo.WitnessPoints
    bpWitnessptsSphere = 3×2
        3.0000    5.1000
       -6.0000   -5.0000
       -7.5000   -7.5000

    Plot a line between the sphere and the closest voxel to it using its witness points.

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    Now perform a narrow-phase check, by using an occupancyMap3DCollisionOptions object with the CheckNarrowPhase property set to true.

    npOpts = occupancyMap3DCollisionOptions(CheckNarrowPhase=true,ReturnDistance=true,ReturnVoxels=true);
    [npIsCollidingSphere,bpResultsSphere] = checkMapCollision(map,sphere,npOpts);

    Return the voxel distance and witness point coordinates for the sphere. The distance and witness points are slightly more accurate this time, because the narrow phase uses the distance between the primitive and the voxel, whereas the broad phase before uses the distance between the axis-aligned bounding box (AABB) of the collision object and the voxel.

    npDist = bpResultsSphere.DistanceInfo.Distance
    npDist = 2.6892
    npWitnesspts = bpResultsSphere.DistanceInfo.WitnessPoints
    npWitnesspts = 3×2
        3.0000    5.2596
       -6.0000   -4.5419
       -7.5000   -7.5000

    Visualize the occupancy map again and plot line showing the shortest distance between the voxel and sphere. The line between the witness points visually appears accurate after performing the narrow-phase check.

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    Extended Capabilities

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    Version History

    Introduced in R2022b