src/bike.rs

@@ -157,31 +157,28 @@ fn wheels_helper(
     };
 
     let xform = Transform::from_translation(position);
-    let hub_mesh: Mesh = Sphere::new(0.1).into();
 
     let hub = commands
         .spawn((
             Name::new("hub"),
+            SpatialBundle::from_transform(xform),
             RigidBody::Dynamic,
             MassPropertiesBundle::new_computed(&Collider::sphere(0.1), 200.0),
-            PbrBundle {
-                mesh: meshes.add(hub_mesh),
-                material: materials.add(wheel_material.clone()),
-                transform: xform,
-                ..Default::default()
-            },
         ))
+        .with_children(|parent| {
+            let mesh: Mesh = Sphere::new(0.1).into();
+            parent.spawn(PbrBundle {
+                mesh: meshes.add(mesh),
+                material: materials.add(wheel_material.clone()),
+                ..Default::default()
+            });
+        })
         .id();
 
     let tire = commands
         .spawn((
             Name::new("tire"),
-            PbrBundle {
+            SpatialBundle::from_transform(xform),
-                mesh: meshes.add(tire_mesh),
-                material: materials.add(wheel_material.clone()),
-                transform: xform,
-                ..Default::default()
-            },
             CyberWheel,
             RigidBody::Dynamic,
             collider,
@@ -193,6 +190,13 @@ fn wheels_helper(
             CollisionMargin(0.05),
             SweptCcd::NON_LINEAR,
         ))
+        .with_children(|p| {
+            p.spawn(PbrBundle {
+                mesh: meshes.add(tire_mesh),
+                material: materials.add(wheel_material.clone()),
+                ..Default::default()
+            });
+        })
         .id();
 
     // connect hubs and tires to make wheels

src/main.rs

@@ -43,7 +43,6 @@ fn ground_and_light(
 ) {
     commands
         .spawn((
-            SpatialBundle::default(),
             RigidBody::Static,
             Collider::cuboid(50.0, 0.5, 50.0),
             CollisionMargin(0.1),
@@ -54,7 +53,7 @@ fn ground_and_light(
             p.spawn(PbrBundle {
                 mesh: meshes.add(Plane3d::default().mesh().size(50.0, 50.0)),
                 material: materials.add(Color::from(SILVER)),
-                transform: Transform::from_xyz(0.0, 0.4, 0.0),
+                transform: Transform::from_xyz(0.0, 1.0, 0.0),
                 ..default()
             });
         });

src/physics.rs

@@ -18,7 +18,7 @@ pub struct CatControllerSettings {
 impl Default for CatControllerSettings {
     fn default() -> Self {
         Self {
-            kp: 1200.0,
+            kp: 950.0,
             kd: 10.0,
             ki: 50.0,
         }