Implement AbstractPath and related API changes to support multiple path types

CHANGELOG.md

@@ -6,6 +6,14 @@ request related to the change, then we may provide the commit.
 
 This is not a comprehensive list of changes but rather a hand-curated collection of the more notable ones. For a comprehensive history, see the [OpenSim Core GitHub repo](https://github.com/opensim-org/opensim-core).
 
+v4.5
+====
+- Added `AbstractPath` which is a base class for `GeometryPath` and other path types (#3388). All path-based forces now 
+own the property `path` of type `AbstractPath` instead of the `GeometryPath` unnamed property. Getters and setters have 
+been added to these forces to provide access to concrete path types (e.g., `updPath<T>`). In `Ligament` and 
+`Blankevoort1991Ligament`, usages of `get_GeometryPath`, `upd_GeometryPath`, etc., need to be been updated to 
+`getGeometryPath`, `updGeometryPath`, etc., or a suitable alternative.    
+
 v4.4.1
 ======
 - IMU::calcGyroscopeSignal() now reports angular velocities in the IMU frame.

OpenSim/Actuators/DeGrooteFregly2016Muscle.cpp

@@ -1020,35 +1020,7 @@ void DeGrooteFregly2016Muscle::replaceMuscles(
                 muscBase.get_ignore_tendon_compliance());
         actu->set_ignore_activation_dynamics(
                 muscBase.get_ignore_activation_dynamics());
-
-        const auto& pathPointSet = muscBase.getGeometryPath().getPathPointSet();
-        auto& geomPath = actu->updGeometryPath();
-        for (int ipp = 0; ipp < pathPointSet.getSize(); ++ipp) {
-            auto* pathPoint = pathPointSet.get(ipp).clone();
-            const auto& socketNames = pathPoint->getSocketNames();
-            for (const auto& socketName : socketNames) {
-                pathPoint->updSocket(socketName)
-                        .connect(pathPointSet.get(ipp)
-                                         .getSocket(socketName)
-                                         .getConnecteeAsObject());
-            }
-            geomPath.updPathPointSet().adoptAndAppend(pathPoint);
-        }
-
-        const auto& pathWrapSet = muscBase.getGeometryPath().getWrapSet();
-        for (int ipw = 0; ipw < pathWrapSet.getSize(); ++ipw) {
-            auto* pathWrap = pathWrapSet.get(ipw).clone();
-            const auto& socketNames = pathWrap->getSocketNames();
-            for (const auto& socketName : socketNames) {
-                pathWrap->updSocket(socketName)
-                        .connect(pathWrapSet.get(ipw)
-                                .getSocket(socketName)
-                                .getConnecteeAsObject());
-            }
-            geomPath.updWrapSet().adoptAndAppend(pathWrap);
-        }
-
-        std::string actname = actu->getName();
+        actu->updProperty_path().assign(muscBase.getProperty_path());
         model.addForce(actu.release());
 
         musclesToDelete.push_back(&muscBase);
@@ -1074,14 +1046,14 @@ void DeGrooteFregly2016Muscle::extendPostScale(
         const SimTK::State& s, const ScaleSet& scaleSet) {
     Super::extendPostScale(s, scaleSet);
 
-    GeometryPath& path = upd_GeometryPath();
+    AbstractPath& path = updPath();
     if (path.getPreScaleLength(s) > 0.0)
     {
         double scaleFactor = path.getLength(s) / path.getPreScaleLength(s);
         upd_optimal_fiber_length() *= scaleFactor;
         upd_tendon_slack_length() *= scaleFactor;
 
-        // Clear the pre-scale length that was stored in the GeometryPath.
+        // Clear the pre-scale length that was stored in the path.
         path.setPreScaleLength(s, 0.0);
     }
 }

OpenSim/Actuators/McKibbenActuator.cpp

@@ -107,7 +107,7 @@ void McKibbenActuator::computeForce(const SimTK::State& s,
 
     double actuation = computeActuation(s);
 
-    getGeometryPath().addInEquivalentForces(s, actuation, bodyForces, generalizedForces);
+    getPath().addInEquivalentForces(s, actuation, bodyForces, generalizedForces);
 }
 //_____________________________________________________________________________
 /**

OpenSim/Actuators/Millard2012AccelerationMuscle.cpp

@@ -557,14 +557,14 @@ extendPostScale(const SimTK::State& s, const ScaleSet& scaleSet)
 
     Super::extendPostScale(s, scaleSet);
 
-    GeometryPath& path = upd_GeometryPath();
+    AbstractPath& path = updPath();
     if (path.getPreScaleLength(s) > 0.0)
     {
         double scaleFactor = path.getLength(s) / path.getPreScaleLength(s);
         upd_optimal_fiber_length() *= scaleFactor;
         upd_tendon_slack_length() *= scaleFactor;
 
-        // Clear the pre-scale length that was stored in the GeometryPath.
+        // Clear the pre-scale length that was stored in the path.
         path.setPreScaleLength(s, 0.0);
     }
 }

OpenSim/Actuators/Millard2012EquilibriumMuscle.cpp

@@ -598,14 +598,14 @@ extendPostScale(const SimTK::State& s, const ScaleSet& scaleSet)
 {
     Super::extendPostScale(s, scaleSet);
 
-    GeometryPath& path = upd_GeometryPath();
+    AbstractPath& path = updPath();
     if (path.getPreScaleLength(s) > 0.0)
     {
         double scaleFactor = path.getLength(s) / path.getPreScaleLength(s);
         upd_optimal_fiber_length() *= scaleFactor;
         upd_tendon_slack_length() *= scaleFactor;
 
-        // Clear the pre-scale length that was stored in the GeometryPath.
+        // Clear the pre-scale length that was stored in the path.
         path.setPreScaleLength(s, 0.0);
     }
 }

OpenSim/Actuators/ModelFactory.cpp

@@ -22,6 +22,7 @@
 #include <OpenSim/Simulation/SimbodyEngine/PinJoint.h>
 #include <OpenSim/Simulation/SimbodyEngine/SliderJoint.h>
 #include <OpenSim/Simulation/SimbodyEngine/WeldJoint.h>
+#include <OpenSim/Simulation/Model/GeometryPath.h>
 #include <OpenSim/Common/CommonUtilities.h>
 
 using namespace OpenSim;
@@ -158,49 +159,21 @@ void ModelFactory::replaceMusclesWithPathActuators(OpenSim::Model &model) {
 
     // Create path actuators from muscle properties and add to the model. Save
     // a list of pointers of the muscles to delete.
+    model.finalizeConnections();
     std::vector<Muscle*> musclesToDelete;
     auto& muscleSet = model.updMuscles();
     for (int im = 0; im < muscleSet.getSize(); ++im) {
         auto& musc = muscleSet.get(im);
-        auto* actu = new PathActuator();
+        auto actu = OpenSim::make_unique<PathActuator>();
         actu->setName(musc.getName());
         musc.setName(musc.getName() + "_delete");
+        actu->set_appliesForce(musc.get_appliesForce());
         actu->setOptimalForce(musc.getMaxIsometricForce());
         actu->setMinControl(musc.getMinControl());
         actu->setMaxControl(musc.getMaxControl());
-
-        model.addForce(actu);
-
-        // For the connectee names in the PathPoints to be correct, we must add
-        // the path points after adding the PathActuator to the model.
-        const auto& pathPointSet = musc.getGeometryPath().getPathPointSet();
-        auto& geomPath = actu->updGeometryPath();
-        for (int ip = 0; ip < pathPointSet.getSize(); ++ip) {
-            auto* pathPoint = pathPointSet.get(ip).clone();
-            const auto& socketNames = pathPoint->getSocketNames();
-            for (const auto& socketName : socketNames) {
-                pathPoint->updSocket(socketName)
-                        .connect(pathPointSet.get(ip)
-                                .getSocket(socketName)
-                                .getConnecteeAsObject());
-            }
-            geomPath.updPathPointSet().adoptAndAppend(pathPoint);
-        }
-
-        // For the connectee names in the PathWraps to be correct, we must add
-        // the path wraps after adding the PathActuator to the model.
-        const auto& pathWrapSet = musc.getGeometryPath().getWrapSet();
-        for (int ipw = 0; ipw < pathWrapSet.getSize(); ++ipw) {
-            auto* pathWrap = pathWrapSet.get(ipw).clone();
-            const auto& socketNames = pathWrap->getSocketNames();
-            for (const auto& socketName : socketNames) {
-                pathWrap->updSocket(socketName)
-                        .connect(pathWrapSet.get(ipw)
-                                .getSocket(socketName)
-                                .getConnecteeAsObject());
-            }
-            geomPath.updWrapSet().adoptAndAppend(pathWrap);
-        }
+        actu->updProperty_path().assign(musc.getProperty_path());
+        actu->upd_path().setDefaultColor({0.5, 0.5, 0.5});
+        model.addForce(actu.release());
 
         musclesToDelete.push_back(&musc);
     }

OpenSim/Actuators/ModelFactory.h

@@ -60,7 +60,7 @@ class OSIMACTUATORS_API ModelFactory {
     /// @name Modify a Model
     /// @{
 
-    /// Replace muscles in a model with a PathActuator of the same GeometryPath,
+    /// Replace muscles in a model with a PathActuator of the same path,
     /// optimal force, and min/max control defaults.
     /// @note This only replaces muscles within the model's ForceSet.
     static void replaceMusclesWithPathActuators(Model& model);

OpenSim/Actuators/RigidTendonMuscle.cpp

@@ -161,7 +161,7 @@ void RigidTendonMuscle::calcMusclePotentialEnergyInfo(const SimTK::State& s,
 void RigidTendonMuscle::calcFiberVelocityInfo(const State& s, FiberVelocityInfo& fvi) const
 {
     /*const MuscleLengthInfo &mli = */getMuscleLengthInfo(s);
-    fvi.fiberVelocity = getGeometryPath().getLengtheningSpeed(s);
+    fvi.fiberVelocity = getPath().getLengtheningSpeed(s);
     fvi.normFiberVelocity = fvi.fiberVelocity / 
                             (getOptimalFiberLength()*getMaxContractionVelocity());
     fvi.fiberForceVelocityMultiplier = 

OpenSim/Common/XMLDocument.cpp

@@ -66,8 +66,9 @@ using namespace std;
 // 30516 for GeometryPath default_color -> Appearance
 // 30517 for removal of _connectee_name suffix to shorten XML for socket, input
 // 40000 for OpenSim 4.0 release 40000
+// 40500 for updating 'GeometryPath' nodes to have property name 'path'.
 
-const int XMLDocument::LatestVersion = 40000;
+const int XMLDocument::LatestVersion = 40500;
 //=============================================================================
 // DESTRUCTOR AND CONSTRUCTOR(S)
 //=============================================================================

OpenSim/Simulation/Model/AbstractPath.cpp

@@ -0,0 +1,68 @@
+/* -------------------------------------------------------------------------- *
+ *                          OpenSim:  AbstractPath.cpp                        *
+ * -------------------------------------------------------------------------- *
+ * The OpenSim API is a toolkit for musculoskeletal modeling and simulation.  *
+ * See http://opensim.stanford.edu and the NOTICE file for more information.  *
+ * OpenSim is developed at Stanford University and supported by the US        *
+ * National Institutes of Health (U54 GM072970, R24 HD065690) and by DARPA    *
+ * through the Warrior Web program.                                           *
+ *                                                                            *
+ * Copyright (c) 2005-2023 Stanford University and the Authors                *
+ * Author(s): Nicholas Bianco, Joris Verhagen, Adam Kewley                    *
+ *                                                                            *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may    *
+ * not use this file except in compliance with the License. You may obtain a  *
+ * copy of the License at http://www.apache.org/licenses/LICENSE-2.0.         *
+ *                                                                            *
+ * Unless required by applicable law or agreed to in writing, software        *
+ * distributed under the License is distributed on an "AS IS" BASIS,          *
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   *
+ * See the License for the specific language governing permissions and        *
+ * limitations under the License.                                             *
+ * -------------------------------------------------------------------------- */
+
+#include "AbstractPath.h"
+#include "Appearance.h"
+
+using namespace OpenSim;
+
+AbstractPath::AbstractPath() : ModelComponent() {
+    setAuthors("Nicholas Bianco, Joris Verhagen, Adam Kewley");
+
+    Appearance appearance;
+    appearance.set_color(SimTK::Gray);
+    constructProperty_Appearance(appearance);
+}
+
+AbstractPath::AbstractPath(AbstractPath const&) = default;
+
+AbstractPath::~AbstractPath() noexcept = default;
+
+AbstractPath& AbstractPath::operator=(const AbstractPath&) = default;
+
+AbstractPath::AbstractPath(AbstractPath&& other) = default;
+
+AbstractPath& AbstractPath::operator=(AbstractPath&& other) = default;
+
+// DEFAULTED METHODS
+const SimTK::Vec3& AbstractPath::getDefaultColor() const
+{
+    return get_Appearance().get_color();
+}
+
+void AbstractPath::setDefaultColor(const SimTK::Vec3& color)
+{
+    updProperty_Appearance().setValueIsDefault(false);
+    upd_Appearance().set_color(color);
+}
+
+double AbstractPath::getPreScaleLength(const SimTK::State&) const
+{
+    return _preScaleLength;
+}
+
+void AbstractPath::setPreScaleLength(const SimTK::State&,
+        double preScaleLength)
+{
+    _preScaleLength = preScaleLength;
+}