/**
* Add extra joints to the SIMM model to represent the joint location/orientation
* in the parent body and in the child body.
*
* @param aJoint The Simbody joint.
* @param rParentName The name of the parent body for the "real" joint.
* @param rChildName The name of the child body for the "real" joint.
* @return Whether or not a 'parent' joint was added.
*/
bool SimbodySimmModel::addExtraJoints(const OpenSim::Joint& aJoint, string& rParentName, string& rChildName)
{
SimTK::Vec3 location(0);
SimTK::Vec3 orientation(0);
bool parentJointAdded = false;
if (isParentJointNeeded(aJoint)) {
const PhysicalOffsetFrame* offset =
dynamic_cast<const PhysicalOffsetFrame*>(&aJoint.getParentFrame());
if (offset) {
location = offset->get_translation();
orientation = offset->get_orientation();
}
string bodyName = aJoint.getChildFrame().getName() + "_pjc";
SimbodySimmBody* b = new SimbodySimmBody(NULL, bodyName);
_simmBody.append(b);
makeSimmJoint(aJoint.getName() + "_pjc",
aJoint.getParentFrame().getName(), bodyName, location, orientation);
rParentName = bodyName;
parentJointAdded = true;
} else {
rParentName = aJoint.getParentFrame().getName();
parentJointAdded = false;
}
location = 0;
orientation = 0;
if (isChildJointNeeded(aJoint)) {
const PhysicalOffsetFrame* offset =
dynamic_cast<const PhysicalOffsetFrame*>(&aJoint.getChildFrame());
if (offset) {
location = offset->get_translation();
orientation = offset->get_orientation();
}
string bodyName = aJoint.getChildFrame().getName() + "_jcc";
SimbodySimmBody* b = new SimbodySimmBody(NULL, bodyName);
_simmBody.append(b);
// This joint is specified in the reverse direction.
makeSimmJoint(aJoint.getName() + "_jcc",
aJoint.getChildFrame().getName(), bodyName, location, orientation);
rChildName = bodyName;
} else {
rChildName = aJoint.getChildFrame().getName();
}
return parentJointAdded;
}
/**
* Check to see if a location (in child) and orientation (in child) are all zeros.
* If they are not, then a separate SIMM joint is needed to hold this transform.
*
* @param aJoint The Simbody joint to check.
* @return Whether or not a separate SIMM joint is needed to represent the location
* and orientation in child.
*/
bool SimbodySimmModel::isChildJointNeeded(const OpenSim::Joint& aJoint)
{
SimTK::Vec3 location(0);
SimTK::Vec3 orientation(0);
const PhysicalOffsetFrame* offset =
dynamic_cast<const PhysicalOffsetFrame*>(&aJoint.getChildFrame());
if (offset) {
location = offset->get_translation();
orientation = offset->get_orientation();
}
else {
return false;
}
double sum = location.scalarNormSqr();
if (NOT_EQUAL_WITHIN_ERROR(sum, 0.0))
return true;
sum = orientation.scalarNormSqr();
if (NOT_EQUAL_WITHIN_ERROR(sum, 0.0))
return true;
return false;
}