Physics "Getting Started" documentation sample throws exception

I am tryiyng to get the ECS Physics Getting Started sample to work using Unity 2019.2.

Using the exact code from:

Creating bodies from scratch


When this line is being executed:

 entityManager.AddComponentData(entity, new Translation { Value = position });

The following exception is raised:

ArgumentException: The component of type:Translation has already been added to the entity.

Unity.Entities.EntityComponentStore.AssertCanAddComponent (Unity.Entities.Entity entity, Unity.Entities.ComponentType componentType) (at Library/PackageCache/com.unity.entities@0.1.1-preview/Unity.Entities/EntityComponentStoreDebug.cs:232)

Unity.Entities.EntityManager.AddComponent (Unity.Entities.Entity entity, Unity.Entities.ComponentType componentType, System.Boolean ignoreDuplicateAdd) (at Library/PackageCache/com.unity.entities@0.1.1-preview/Unity.Entities/EntityManagerChangeArchetype.cs:697)

Unity.Entities.EntityManager.AddComponentData[T] (Unity.Entities.Entity entity, T componentData) (at Library/PackageCache/com.unity.entities@0.1.1-preview/Unity.Entities/EntityManagerChangeArchetype.cs:404)

SpawnPhysics.CreateBody (Unity.Rendering.RenderMesh displayMesh, Unity.Mathematics.float3 position, Unity.Mathematics.quaternion orientation, Unity.Entities.BlobAssetReference`1[T] collider, Unity.Mathematics.float3 linearVelocity, Unity.Mathematics.float3 angularVelocity, System.Single mass, System.Boolean isDynamic) (at Assets/_Scripts/ECS/SpawnPhysics.cs:55)

SpawnPhysics.Start () (at Assets/_Scripts/ECS/SpawnPhysics.cs:30)

 

Thanks for the headsup on this. We'll get it fixed and add a simple sample that uses the docs code to make sure it stays correct. You can just change entityManager.AddComponentData to SetComponentData instead, if the component is already there. The entityManager.HasComponent is useful to check if you need to Add or Set a ComponentData