collisions.py

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from os.path import abspath, dirname, join
 
import pinocchio as pin
 
pinocchio_model_dir = join(dirname(dirname(str(abspath(__file__)))), "models")
 
model_path = join(pinocchio_model_dir, "example-robot-data/robots")
mesh_dir = pinocchio_model_dir
urdf_filename = "romeo_small.urdf"
urdf_model_path = join(join(model_path, "romeo_description/urdf"), urdf_filename)
 
# Load model
model = pin.buildModelFromUrdf(urdf_model_path, pin.JointModelFreeFlyer())
 
# Load collision geometries
geom_model = pin.buildGeomFromUrdf(
    model, urdf_model_path, pin.GeometryType.COLLISION, mesh_dir
)
 
# Add collisition pairs
geom_model.addAllCollisionPairs()
print("num collision pairs - initial:", len(geom_model.collisionPairs))
 
# Remove collision pairs listed in the SRDF file
srdf_filename = "romeo.srdf"
srdf_model_path = model_path + "/romeo_description/srdf/" + srdf_filename
 
pin.removeCollisionPairs(model, geom_model, srdf_model_path)
print(
    "num collision pairs - after removing useless collision pairs:",
    len(geom_model.collisionPairs),
)
 
# Load reference configuration
pin.loadReferenceConfigurations(model, srdf_model_path)
 
# Retrieve the half sitting position from the SRDF file
q = model.referenceConfigurations["half_sitting"]
 
# Create data structures
data = model.createData()
geom_data = pin.GeometryData(geom_model)
 
 
# Compute all the collisions
pin.computeCollisions(model, data, geom_model, geom_data, q, False)
 
# Print the status of collision for all collision pairs
for k in range(len(geom_model.collisionPairs)):
    cr = geom_data.collisionResults[k]
    cp = geom_model.collisionPairs[k]
    print(
        "collision pair:",
        cp.first,
        ",",
        cp.second,
        "- collision:",
        "Yes" if cr.isCollision() else "No",
    )
 
# Compute for a single pair of collision
pin.updateGeometryPlacements(model, data, geom_model, geom_data, q)
pin.computeCollision(geom_model, geom_data, 0)