Migration from Gazebo-classic: Model API
When migrating plugins from Gazebo-classic to Gazebo, developers will notice that the C++ APIs for both simulators are quite different. Be sure to check the plugin migration tutorial to get a high-level view of the architecture differences before using this guide.
This tutorial is meant to serve as a reference guide for developers migrating functions from the sim::physics::Model class.
If you're trying to use some API which doesn't have an equivalent on Gazebo yet, feel free to ticket an issue.
Model API
Gazebo-classic's sim::physics::Model provides lots of functionality, which can be divided in these categories:
- Properties: Setting / getting properties
- Example: Model::GetName / Model::SetName
- Read family: Getting children and parent
- Example: Model::GetLink
- Write family: Adding children, changing parent
- Example: Model::RemoveChildren
- Lifecycle: Functions to control the model's lifecycle
- Example: Model::Init
- Others: Functions that don't fit any of the categories above
- Example: Model::PlaceOnEntity
You'll find the Gazebo APIs below on the following headers:
It's worth remembering that most of this functionality can be performed using the EntityComponentManager directly. The functions presented here exist for convenience and readability.
Properties
Most of Gazebo-classic's Model API is related to setting and getting properties. These functions are great candidates to have equivalents on Gazebo Gazebo, because the Entity-Component-System architecture is perfect for setting components (properties) into entities such as models.
| Classic | Gazebo |
|---|---|
| AddType | ecm.CreateComponent<Type>(entity, Type()) |
| BoundingBox | TODO |
| CollisionBoundingBox | TODO |
| DirtyPose | Not supported |
| FillMsg | TODO |
| GetAutoDisable | TODO |
| GetId | gz::sim::Model::Entity |
| GetName | gz::sim::Model::Name |
| GetPluginCount | TODO |
| GetSDF | TODO |
| GetSDFDom | TODO |
| GetSaveable | Not supported |
| GetScopedName | gz::sim::scopedName |
| GetSelfCollide | gz::sim::Model::SelfCollide |
| GetType | gz::sim::entityType |
| GetWorldEnergy | TODO |
| GetWorldEnergyKinetic | TODO |
| GetWorldEnergyPotential | TODO |
| HasType | sim::components::Model::typeId == entityTypeId(entity, ecm) |
| InitialRelativePose | TODO |
| IsCanonicalLink | See link API |
| IsSelected | Selection is client-specific, not porting |
| IsStatic | gz::sim::Model::Static |
| PluginInfo | TODO |
| TODO | |
| ProcessMsg | TODO |
| RelativeAngularAccel | TODO |
| RelativeAngularVel | TODO |
| RelativeLinearAccel | TODO |
| RelativeLinearVel | TODO |
| RelativePose | TODO |
| SDFPoseRelativeToParent | TODO |
| SDFSemanticPose | TODO |
| Scale | TODO |
| SensorScopedName | TODO |
| SetAngularVel | TODO |
| SetAnimation | TODO |
| SetAutoDisable | TODO |
| SetCollideMode | TODO |
| SetEnabled | TODO |
| SetGravityMode | TODO |
| SetInitialRelativePose | TODO |
| SetJointAnimation | TODO |
| SetJointPosition | See joint API |
| SetJointPositions | See joint API |
| SetLaserRetro | TODO |
| SetLinearVel | TODO |
| SetLinkWorldPose | See link API |
| SetName | TODO |
| SetRelativePose | TODO |
| SetSaveable | Not supported |
| SetScale | TODO |
| SetSelected | Selection is client-specific, not porting |
| SetSelfCollide | TODO |
| SetState | TODO |
| SetStatic | TODO |
| SetWindMode | TODO |
| SetWorldPose | gz::sim::Model::SetWorldPoseCmd |
| SetWorldTwist | TODO |
| StopAnimation | TODO |
| TypeStr | gz::sim::entityTypeStr |
| URI | TODO |
| UnscaledSDF | TODO |
| UpdateParameters | TODO |
| WindMode | gz::sim::Model::WindMode |
| WorldAngularAccel | TODO |
| WorldAngularVel | TODO |
| WorldLinearAccel | TODO |
| WorldLinearVel | TODO |
| WorldPose | gz::sim::worldPose |
Read family
These APIs deal with reading information related to child / parent relationships.
The main difference in these APIs across Gazebo generations is that on classic, they deal with shared pointers to entities, while on Gazebo, they deal with entity IDs.
| Classic | Gazebo |
|---|---|
| GetByName | Use type-specific gz::sim::Model::*ByName |
| GetChild | Use type-specific gz::sim::Model::*ByName |
| GetChildCollision | See link API |
| GetChildCount | Use type-specific gz::sim::Model::*Count |
| GetChildLink | gz::sim::Model::LinkByName |
| GetGripper | TODO |
| GetGripperCount | TODO |
| GetJoint | gz::sim::Model::JointByName |
| GetJointCount | gz::sim::Model::JointCount |
| GetJoints | gz::sim::Model::Joints |
| GetLink | gz::sim::Model::LinkByName |
| GetLinks | const gz::sim::Model::Links |
| GetParent | gz::sim::EntiyComponentManager::ParentEntity |
| GetParentId | gz::sim::EntiyComponentManager::ParentEntity |
| GetParentModel | gz::sim::EntiyComponentManager::ParentEntity |
| GetSensorCount | See link API |
| GetWorld | const gz::sim::Model::World |
| NestedModel | gz::sim::Model::NestedModelByName |
| NestedModels | const gz::sim::Model::NestedModels |
Write family
These functions deal with modifying the entity tree, attaching children to new parents.
| Classic | Gazebo |
|---|---|
| AddChild | TODO |
| AttachStaticModel | TODO |
| CreateJoint | TODO |
| CreateLink | TODO |
| DetachStaticModel | TODO |
| RemoveChild | TODO |
| RemoveChildren | TODO |
| RemoveJoint | TODO |
| SetCanonicalLink | TODO |
| SetParent | TODO |
| SetWorld | TODO |
Lifecycle
These functions aren't related to the state of a model, but perform some processing related to the model's lifecycle, like initializing, updating or terminating it.
| Classic | Gazebo |
|---|---|
| Fini | N/A |
| Init | N/A |
| Load | gz::sim::SdfEntityCreator::CreateEntities |
| LoadJoints | gz::sim::SdfEntityCreator::CreateEntities |
| LoadPlugins | TODO |
| Reset | TODO |
| ResetPhysicsStates | TODO |
| Update | Entities are updated by systems |
Others
Miscelaneous functions that don't fit the other categories. Most of them involve logic that should be performed from within a system.
| Classic | Gazebo |
|---|---|
| GetJointController | Use this system: gz::sim::systems::JointController |
| GetNearestEntityBelow | Requires a system |
| PlaceOnEntity | Requires a system |
| PlaceOnNearestEntityBelow | Requires a system |