Allow the removal of a collider.

src/geometry/broad_phase_multi_sap.rs

@@ -662,7 +662,7 @@ mod test {
         let rb = RigidBodyBuilder::new_dynamic().build();
         let co = ColliderBuilder::ball(0.5).build();
         let hrb = bodies.insert(rb);
-        let hco = colliders.insert(co, hrb, &mut bodies);
+        colliders.insert(co, hrb, &mut bodies);
 
         broad_phase.update_aabbs(0.0, &bodies, &mut colliders);
 
@@ -681,7 +681,7 @@ mod test {
         let rb = RigidBodyBuilder::new_dynamic().build();
         let co = ColliderBuilder::ball(0.5).build();
         let hrb = bodies.insert(rb);
-        let hco = colliders.insert(co, hrb, &mut bodies);
+        colliders.insert(co, hrb, &mut bodies);
 
         // Make sure the proxy handles is recycled properly.
         broad_phase.update_aabbs(0.0, &bodies, &mut colliders);

src/geometry/collider.rs

@@ -3,7 +3,7 @@ use crate::geometry::{
     Ball, Capsule, ColliderGraphIndex, Contact, Cuboid, HeightField, InteractionGraph, Polygon,
     Proximity, Triangle, Trimesh,
 };
-use crate::math::{Isometry, Point, Vector};
+use crate::math::{AngVector, Isometry, Point, Rotation, Vector};
 use na::Point3;
 use ncollide::bounding_volume::{HasBoundingVolume, AABB};
 use num::Zero;
@@ -159,6 +159,11 @@ impl Collider {
         &self.position
     }
 
+    /// The position of this collider wrt the body it is attached to.
+    pub fn position_wrt_parent(&self) -> &Isometry<f32> {
+        &self.delta
+    }
+
     /// The density of this collider.
     pub fn density(&self) -> f32 {
         self.density
@@ -347,7 +352,41 @@ impl ColliderBuilder {
         self
     }
 
+    /// Sets the initial translation of the collider to be created,
+    /// relative to the rigid-body it is attached to.
+    #[cfg(feature = "dim2")]
+    pub fn translation(mut self, x: f32, y: f32) -> Self {
+        self.delta.translation.x = x;
+        self.delta.translation.y = y;
+        self
+    }
+
+    /// Sets the initial translation of the collider to be created,
+    /// relative to the rigid-body it is attached to.
+    #[cfg(feature = "dim3")]
+    pub fn translation(mut self, x: f32, y: f32, z: f32) -> Self {
+        self.delta.translation.x = x;
+        self.delta.translation.y = y;
+        self.delta.translation.z = z;
+        self
+    }
+
+    /// Sets the initial orientation of the collider to be created,
+    /// relative to the rigid-body it is attached to.
+    pub fn rotation(mut self, angle: AngVector<f32>) -> Self {
+        self.delta.rotation = Rotation::new(angle);
+        self
+    }
+
+    /// Sets the initial position (translation and orientation) of the collider to be created,
+    /// relative to the rigid-body it is attached to.
+    pub fn position(mut self, pos: Isometry<f32>) -> Self {
+        self.delta = pos;
+        self
+    }
+
     /// Set the position of this collider in the local-space of the rigid-body it is attached to.
+    #[deprecated(note = "Use `.position` instead.")]
     pub fn delta(mut self, delta: Isometry<f32>) -> Self {
         self.delta = delta;
         self

src/geometry/collider_set.rs

@@ -47,7 +47,6 @@ impl ColliderSet {
         parent_handle: RigidBodyHandle,
         bodies: &mut RigidBodySet,
     ) -> ColliderHandle {
-        let mass_properties = coll.mass_properties();
         coll.parent = parent_handle;
         let parent = bodies
             .get_mut_internal(parent_handle)
@@ -55,9 +54,8 @@ impl ColliderSet {
         coll.position = parent.position * coll.delta;
         coll.predicted_position = parent.predicted_position * coll.delta;
         let handle = self.colliders.insert(coll);
-        parent.colliders.push(handle);
-        parent.mass_properties += mass_properties;
-        parent.update_world_mass_properties();
+        let coll = self.colliders.get(handle).unwrap();
+        parent.add_collider_internal(handle, &coll);
         bodies.activate(parent_handle);
         handle
     }