Rotation locking: apply filter only to the world inertia properties to fix the multi-collider case.

23 files changed, 143 insertions, 135 deletions

diff --git a/src/dynamics/solver/joint_constraint/ball_position_constraint.rs b/src/dynamics/solver/joint_constraint/ball_position_constraint.rs
index 8bc9072..744c00d 100644
--- a/src/dynamics/solver/joint_constraint/ball_position_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/ball_position_constraint.rs
@@ -27,10 +27,10 @@ impl BallPositionConstraint {
         Self {
             local_com1: rb1.mass_properties.local_com,
             local_com2: rb2.mass_properties.local_com,
-            im1: rb1.mass_properties.inv_mass,
-            im2: rb2.mass_properties.inv_mass,
-            ii1: rb1.world_inv_inertia_sqrt.squared(),
-            ii2: rb2.world_inv_inertia_sqrt.squared(),
+            im1: rb1.effective_inv_mass,
+            im2: rb2.effective_inv_mass,
+            ii1: rb1.effective_world_inv_inertia_sqrt.squared(),
+            ii2: rb2.effective_world_inv_inertia_sqrt.squared(),
             local_anchor1: cparams.local_anchor1,
             local_anchor2: cparams.local_anchor2,
             position1: rb1.active_set_offset,
@@ -115,8 +115,8 @@ impl BallPositionGroundConstraint {
             // already been flipped by the caller.
             Self {
                 anchor1: rb1.predicted_position * cparams.local_anchor2,
-                im2: rb2.mass_properties.inv_mass,
-                ii2: rb2.world_inv_inertia_sqrt.squared(),
+                im2: rb2.effective_inv_mass,
+                ii2: rb2.effective_world_inv_inertia_sqrt.squared(),
                 local_anchor2: cparams.local_anchor1,
                 position2: rb2.active_set_offset,
                 local_com2: rb2.mass_properties.local_com,
@@ -124,8 +124,8 @@ impl BallPositionGroundConstraint {
         } else {
             Self {
                 anchor1: rb1.predicted_position * cparams.local_anchor1,
-                im2: rb2.mass_properties.inv_mass,
-                ii2: rb2.world_inv_inertia_sqrt.squared(),
+                im2: rb2.effective_inv_mass,
+                ii2: rb2.effective_world_inv_inertia_sqrt.squared(),
                 local_anchor2: cparams.local_anchor2,
                 position2: rb2.active_set_offset,
                 local_com2: rb2.mass_properties.local_com,
diff --git a/src/dynamics/solver/joint_constraint/ball_position_constraint_wide.rs b/src/dynamics/solver/joint_constraint/ball_position_constraint_wide.rs
index 2f2ffc3..043eea7 100644
--- a/src/dynamics/solver/joint_constraint/ball_position_constraint_wide.rs
+++ b/src/dynamics/solver/joint_constraint/ball_position_constraint_wide.rs
@@ -31,14 +31,14 @@ impl WBallPositionConstraint {
     ) -> Self {
         let local_com1 = Point::from(array![|ii| rbs1[ii].mass_properties.local_com; SIMD_WIDTH]);
         let local_com2 = Point::from(array![|ii| rbs2[ii].mass_properties.local_com; SIMD_WIDTH]);
-        let im1 = SimdReal::from(array![|ii| rbs1[ii].mass_properties.inv_mass; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im1 = SimdReal::from(array![|ii| rbs1[ii].effective_inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii1 = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs1[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs1[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         )
         .squared();
         let ii2 = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         )
         .squared();
         let local_anchor1 = Point::from(array![|ii| cparams[ii].local_anchor1; SIMD_WIDTH]);
@@ -141,9 +141,9 @@ impl WBallPositionGroundConstraint {
             } else {
                 cparams[ii].local_anchor1
             }; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2 = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         )
         .squared();
         let local_anchor2 = Point::from(array![|ii| if flipped[ii] {
diff --git a/src/dynamics/solver/joint_constraint/ball_velocity_constraint.rs b/src/dynamics/solver/joint_constraint/ball_velocity_constraint.rs
index 75e19d3..e75f978 100644
--- a/src/dynamics/solver/joint_constraint/ball_velocity_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/ball_velocity_constraint.rs
@@ -40,8 +40,8 @@ impl BallVelocityConstraint {
 
         let vel1 = rb1.linvel + rb1.angvel.gcross(anchor1);
         let vel2 = rb2.linvel + rb2.angvel.gcross(anchor2);
-        let im1 = rb1.mass_properties.inv_mass;
-        let im2 = rb2.mass_properties.inv_mass;
+        let im1 = rb1.effective_inv_mass;
+        let im2 = rb2.effective_inv_mass;
 
         let rhs = -(vel1 - vel2);
         let lhs;
@@ -52,12 +52,12 @@ impl BallVelocityConstraint {
         #[cfg(feature = "dim3")]
         {
             lhs = rb2
-                .world_inv_inertia_sqrt
+                .effective_world_inv_inertia_sqrt
                 .squared()
                 .quadform(&cmat2)
                 .add_diagonal(im2)
                 + rb1
-                    .world_inv_inertia_sqrt
+                    .effective_world_inv_inertia_sqrt
                     .squared()
                     .quadform(&cmat1)
                     .add_diagonal(im1);
@@ -67,8 +67,8 @@ impl BallVelocityConstraint {
         // it's just easier that way.
         #[cfg(feature = "dim2")]
         {
-            let ii1 = rb1.world_inv_inertia_sqrt.squared();
-            let ii2 = rb2.world_inv_inertia_sqrt.squared();
+            let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
+            let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
             let m11 = im1 + im2 + cmat1.x * cmat1.x * ii1 + cmat2.x * cmat2.x * ii2;
             let m12 = cmat1.x * cmat1.y * ii1 + cmat2.x * cmat2.y * ii2;
             let m22 = im1 + im2 + cmat1.y * cmat1.y * ii1 + cmat2.y * cmat2.y * ii2;
@@ -88,8 +88,8 @@ impl BallVelocityConstraint {
             r2: anchor2,
             rhs,
             inv_lhs,
-            ii1_sqrt: rb1.world_inv_inertia_sqrt,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii1_sqrt: rb1.effective_world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
         }
     }
 
@@ -170,7 +170,7 @@ impl BallVelocityGroundConstraint {
             )
         };
 
-        let im2 = rb2.mass_properties.inv_mass;
+        let im2 = rb2.effective_inv_mass;
         let vel1 = rb1.linvel + rb1.angvel.gcross(anchor1);
         let vel2 = rb2.linvel + rb2.angvel.gcross(anchor2);
         let rhs = vel2 - vel1;
@@ -182,7 +182,7 @@ impl BallVelocityGroundConstraint {
         #[cfg(feature = "dim3")]
         {
             lhs = rb2
-                .world_inv_inertia_sqrt
+                .effective_world_inv_inertia_sqrt
                 .squared()
                 .quadform(&cmat2)
                 .add_diagonal(im2);
@@ -190,7 +190,7 @@ impl BallVelocityGroundConstraint {
 
         #[cfg(feature = "dim2")]
         {
-            let ii2 = rb2.world_inv_inertia_sqrt.squared();
+            let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
             let m11 = im2 + cmat2.x * cmat2.x * ii2;
             let m12 = cmat2.x * cmat2.y * ii2;
             let m22 = im2 + cmat2.y * cmat2.y * ii2;
@@ -207,7 +207,7 @@ impl BallVelocityGroundConstraint {
             r2: anchor2,
             rhs,
             inv_lhs,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
         }
     }
 
diff --git a/src/dynamics/solver/joint_constraint/ball_velocity_constraint_wide.rs b/src/dynamics/solver/joint_constraint/ball_velocity_constraint_wide.rs
index 697221b..95b0bb5 100644
--- a/src/dynamics/solver/joint_constraint/ball_velocity_constraint_wide.rs
+++ b/src/dynamics/solver/joint_constraint/ball_velocity_constraint_wide.rs
@@ -42,9 +42,9 @@ impl WBallVelocityConstraint {
         let linvel1 = Vector::from(array![|ii| rbs1[ii].linvel; SIMD_WIDTH]);
         let angvel1 = AngVector::<SimdReal>::from(array![|ii| rbs1[ii].angvel; SIMD_WIDTH]);
         let world_com1 = Point::from(array![|ii| rbs1[ii].world_com; SIMD_WIDTH]);
-        let im1 = SimdReal::from(array![|ii| rbs1[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im1 = SimdReal::from(array![|ii| rbs1[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii1_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs1[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs1[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda1 = array![|ii| rbs1[ii].active_set_offset; SIMD_WIDTH];
 
@@ -52,9 +52,9 @@ impl WBallVelocityConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
@@ -228,9 +228,9 @@ impl WBallVelocityGroundConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
diff --git a/src/dynamics/solver/joint_constraint/fixed_position_constraint.rs b/src/dynamics/solver/joint_constraint/fixed_position_constraint.rs
index cf9dcb7..7e8fc97 100644
--- a/src/dynamics/solver/joint_constraint/fixed_position_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/fixed_position_constraint.rs
@@ -21,10 +21,10 @@ pub(crate) struct FixedPositionConstraint {
 
 impl FixedPositionConstraint {
     pub fn from_params(rb1: &RigidBody, rb2: &RigidBody, cparams: &FixedJoint) -> Self {
-        let ii1 = rb1.world_inv_inertia_sqrt.squared();
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
-        let im1 = rb1.mass_properties.inv_mass;
-        let im2 = rb2.mass_properties.inv_mass;
+        let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
+        let im1 = rb1.effective_inv_mass;
+        let im2 = rb2.effective_inv_mass;
         let lin_inv_lhs = 1.0 / (im1 + im2);
         let ang_inv_lhs = (ii1 + ii2).inverse();
 
@@ -111,8 +111,8 @@ impl FixedPositionGroundConstraint {
             anchor1,
             local_anchor2,
             position2: rb2.active_set_offset,
-            im2: rb2.mass_properties.inv_mass,
-            ii2: rb2.world_inv_inertia_sqrt.squared(),
+            im2: rb2.effective_inv_mass,
+            ii2: rb2.effective_world_inv_inertia_sqrt.squared(),
             local_com2: rb2.mass_properties.local_com,
             impulse: 0.0,
         }
diff --git a/src/dynamics/solver/joint_constraint/fixed_velocity_constraint.rs b/src/dynamics/solver/joint_constraint/fixed_velocity_constraint.rs
index 715b7dd..2868d4b 100644
--- a/src/dynamics/solver/joint_constraint/fixed_velocity_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/fixed_velocity_constraint.rs
@@ -51,10 +51,10 @@ impl FixedVelocityConstraint {
     ) -> Self {
         let anchor1 = rb1.position * cparams.local_anchor1;
         let anchor2 = rb2.position * cparams.local_anchor2;
-        let im1 = rb1.mass_properties.inv_mass;
-        let im2 = rb2.mass_properties.inv_mass;
-        let ii1 = rb1.world_inv_inertia_sqrt.squared();
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
+        let im1 = rb1.effective_inv_mass;
+        let im2 = rb2.effective_inv_mass;
+        let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
         let r1 = anchor1.translation.vector - rb1.world_com.coords;
         let r2 = anchor2.translation.vector - rb2.world_com.coords;
         let rmat1 = r1.gcross_matrix();
@@ -118,8 +118,8 @@ impl FixedVelocityConstraint {
             im2,
             ii1,
             ii2,
-            ii1_sqrt: rb1.world_inv_inertia_sqrt,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii1_sqrt: rb1.effective_world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
             impulse: cparams.impulse * params.warmstart_coeff,
             inv_lhs,
             r1,
@@ -248,8 +248,8 @@ impl FixedVelocityGroundConstraint {
 
         let r1 = anchor1.translation.vector - rb1.world_com.coords;
 
-        let im2 = rb2.mass_properties.inv_mass;
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
+        let im2 = rb2.effective_inv_mass;
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
         let r2 = anchor2.translation.vector - rb2.world_com.coords;
         let rmat2 = r2.gcross_matrix();
 
@@ -304,7 +304,7 @@ impl FixedVelocityGroundConstraint {
             mj_lambda2: rb2.active_set_offset,
             im2,
             ii2,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
             impulse: cparams.impulse * params.warmstart_coeff,
             inv_lhs,
             r2,
diff --git a/src/dynamics/solver/joint_constraint/fixed_velocity_constraint_wide.rs b/src/dynamics/solver/joint_constraint/fixed_velocity_constraint_wide.rs
index 48a6cba..a8d7e91 100644
--- a/src/dynamics/solver/joint_constraint/fixed_velocity_constraint_wide.rs
+++ b/src/dynamics/solver/joint_constraint/fixed_velocity_constraint_wide.rs
@@ -61,9 +61,9 @@ impl WFixedVelocityConstraint {
         let linvel1 = Vector::from(array![|ii| rbs1[ii].linvel; SIMD_WIDTH]);
         let angvel1 = AngVector::<SimdReal>::from(array![|ii| rbs1[ii].angvel; SIMD_WIDTH]);
         let world_com1 = Point::from(array![|ii| rbs1[ii].world_com; SIMD_WIDTH]);
-        let im1 = SimdReal::from(array![|ii| rbs1[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im1 = SimdReal::from(array![|ii| rbs1[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii1_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs1[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs1[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda1 = array![|ii| rbs1[ii].active_set_offset; SIMD_WIDTH];
 
@@ -71,9 +71,9 @@ impl WFixedVelocityConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
@@ -315,9 +315,9 @@ impl WFixedVelocityGroundConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
diff --git a/src/dynamics/solver/joint_constraint/prismatic_position_constraint.rs b/src/dynamics/solver/joint_constraint/prismatic_position_constraint.rs
index 2616f6b..ea7e927 100644
--- a/src/dynamics/solver/joint_constraint/prismatic_position_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/prismatic_position_constraint.rs
@@ -28,10 +28,10 @@ pub(crate) struct PrismaticPositionConstraint {
 
 impl PrismaticPositionConstraint {
     pub fn from_params(rb1: &RigidBody, rb2: &RigidBody, cparams: &PrismaticJoint) -> Self {
-        let ii1 = rb1.world_inv_inertia_sqrt.squared();
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
-        let im1 = rb1.mass_properties.inv_mass;
-        let im2 = rb2.mass_properties.inv_mass;
+        let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
+        let im1 = rb1.effective_inv_mass;
+        let im2 = rb2.effective_inv_mass;
         let lin_inv_lhs = 1.0 / (im1 + im2);
         let ang_inv_lhs = (ii1 + ii2).inverse();
 
diff --git a/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint.rs b/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint.rs
index 78dc1b5..9b82ea5 100644
--- a/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint.rs
@@ -92,13 +92,13 @@ impl PrismaticVelocityConstraint {
         // simplifications of the computation without introducing
         // much instabilities.
 
-        let im1 = rb1.mass_properties.inv_mass;
-        let ii1 = rb1.world_inv_inertia_sqrt.squared();
+        let im1 = rb1.effective_inv_mass;
+        let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
         let r1 = anchor1 - rb1.world_com;
         let r1_mat = r1.gcross_matrix();
 
-        let im2 = rb2.mass_properties.inv_mass;
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
+        let im2 = rb2.effective_inv_mass;
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
         let r2 = anchor2 - rb2.world_com;
         let r2_mat = r2.gcross_matrix();
 
@@ -176,9 +176,9 @@ impl PrismaticVelocityConstraint {
             mj_lambda1: rb1.active_set_offset,
             mj_lambda2: rb2.active_set_offset,
             im1,
-            ii1_sqrt: rb1.world_inv_inertia_sqrt,
+            ii1_sqrt: rb1.effective_world_inv_inertia_sqrt,
             im2,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
             impulse: cparams.impulse * params.warmstart_coeff,
             limits_impulse: limits_impulse * params.warmstart_coeff,
             limits_forcedirs,
@@ -388,8 +388,8 @@ impl PrismaticVelocityGroundConstraint {
         // simplifications of the computation without introducing
         // much instabilities.
 
-        let im2 = rb2.mass_properties.inv_mass;
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
+        let im2 = rb2.effective_inv_mass;
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
         let r1 = anchor1 - rb1.world_com;
         let r2 = anchor2 - rb2.world_com;
         let r2_mat = r2.gcross_matrix();
@@ -465,7 +465,7 @@ impl PrismaticVelocityGroundConstraint {
             joint_id,
             mj_lambda2: rb2.active_set_offset,
             im2,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
             impulse: cparams.impulse * params.warmstart_coeff,
             limits_impulse: limits_impulse * params.warmstart_coeff,
             basis1,
diff --git a/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint_wide.rs b/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint_wide.rs
index 8e0a1ab..04ac182 100644
--- a/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint_wide.rs
+++ b/src/dynamics/solver/joint_constraint/prismatic_velocity_constraint_wide.rs
@@ -73,9 +73,9 @@ impl WPrismaticVelocityConstraint {
         let linvel1 = Vector::from(array![|ii| rbs1[ii].linvel; SIMD_WIDTH]);
         let angvel1 = AngVector::<SimdReal>::from(array![|ii| rbs1[ii].angvel; SIMD_WIDTH]);
         let world_com1 = Point::from(array![|ii| rbs1[ii].world_com; SIMD_WIDTH]);
-        let im1 = SimdReal::from(array![|ii| rbs1[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im1 = SimdReal::from(array![|ii| rbs1[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii1_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs1[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs1[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda1 = array![|ii| rbs1[ii].active_set_offset; SIMD_WIDTH];
 
@@ -83,9 +83,9 @@ impl WPrismaticVelocityConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
@@ -431,9 +431,9 @@ impl WPrismaticVelocityGroundConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
diff --git a/src/dynamics/solver/joint_constraint/revolute_position_constraint.rs b/src/dynamics/solver/joint_constraint/revolute_position_constraint.rs
index e46e0e4..19dd451 100644
--- a/src/dynamics/solver/joint_constraint/revolute_position_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/revolute_position_constraint.rs
@@ -26,10 +26,10 @@ pub(crate) struct RevolutePositionConstraint {
 
 impl RevolutePositionConstraint {
     pub fn from_params(rb1: &RigidBody, rb2: &RigidBody, cparams: &RevoluteJoint) -> Self {
-        let ii1 = rb1.world_inv_inertia_sqrt.squared();
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
-        let im1 = rb1.mass_properties.inv_mass;
-        let im2 = rb2.mass_properties.inv_mass;
+        let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
+        let im1 = rb1.effective_inv_mass;
+        let im2 = rb2.effective_inv_mass;
         let lin_inv_lhs = 1.0 / (im1 + im2);
         let ang_inv_lhs = (ii1 + ii2).inverse();
 
diff --git a/src/dynamics/solver/joint_constraint/revolute_velocity_constraint.rs b/src/dynamics/solver/joint_constraint/revolute_velocity_constraint.rs
index e60bd8a..38f56d9 100644
--- a/src/dynamics/solver/joint_constraint/revolute_velocity_constraint.rs
+++ b/src/dynamics/solver/joint_constraint/revolute_velocity_constraint.rs
@@ -52,14 +52,14 @@ impl RevoluteVelocityConstraint {
         //        let basis2 = r21 * basis1;
         // NOTE: to simplify, we use basis2 = basis1.
         // Though we may want to test if that does not introduce any instability.
-        let im1 = rb1.mass_properties.inv_mass;
-        let im2 = rb2.mass_properties.inv_mass;
+        let im1 = rb1.effective_inv_mass;
+        let im2 = rb2.effective_inv_mass;
 
-        let ii1 = rb1.world_inv_inertia_sqrt.squared();
+        let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
         let r1 = anchor1 - rb1.world_com;
         let r1_mat = r1.gcross_matrix();
 
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
         let r2 = anchor2 - rb2.world_com;
         let r2_mat = r2.gcross_matrix();
 
@@ -87,10 +87,10 @@ impl RevoluteVelocityConstraint {
             mj_lambda1: rb1.active_set_offset,
             mj_lambda2: rb2.active_set_offset,
             im1,
-            ii1_sqrt: rb1.world_inv_inertia_sqrt,
+            ii1_sqrt: rb1.effective_world_inv_inertia_sqrt,
             basis1,
             im2,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
             impulse: cparams.impulse * params.warmstart_coeff,
             inv_lhs,
             rhs,
@@ -212,8 +212,8 @@ impl RevoluteVelocityGroundConstraint {
         //            .to_rotation_matrix()
         //            .into_inner();
         //        let basis2 = /*r21 * */ basis1;
-        let im2 = rb2.mass_properties.inv_mass;
-        let ii2 = rb2.world_inv_inertia_sqrt.squared();
+        let im2 = rb2.effective_inv_mass;
+        let ii2 = rb2.effective_world_inv_inertia_sqrt.squared();
         let r1 = anchor1 - rb1.world_com;
         let r2 = anchor2 - rb2.world_com;
         let r2_mat = r2.gcross_matrix();
@@ -240,7 +240,7 @@ impl RevoluteVelocityGroundConstraint {
             joint_id,
             mj_lambda2: rb2.active_set_offset,
             im2,
-            ii2_sqrt: rb2.world_inv_inertia_sqrt,
+            ii2_sqrt: rb2.effective_world_inv_inertia_sqrt,
             impulse: cparams.impulse * params.warmstart_coeff,
             basis1,
             inv_lhs,
diff --git a/src/dynamics/solver/joint_constraint/revolute_velocity_constraint_wide.rs b/src/dynamics/solver/joint_constraint/revolute_velocity_constraint_wide.rs
index 1b8af80..822c2ac 100644
--- a/src/dynamics/solver/joint_constraint/revolute_velocity_constraint_wide.rs
+++ b/src/dynamics/solver/joint_constraint/revolute_velocity_constraint_wide.rs
@@ -43,9 +43,9 @@ impl WRevoluteVelocityConstraint {
         let linvel1 = Vector::from(array![|ii| rbs1[ii].linvel; SIMD_WIDTH]);
         let angvel1 = AngVector::<SimdReal>::from(array![|ii| rbs1[ii].angvel; SIMD_WIDTH]);
         let world_com1 = Point::from(array![|ii| rbs1[ii].world_com; SIMD_WIDTH]);
-        let im1 = SimdReal::from(array![|ii| rbs1[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im1 = SimdReal::from(array![|ii| rbs1[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii1_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs1[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs1[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda1 = array![|ii| rbs1[ii].active_set_offset; SIMD_WIDTH];
 
@@ -53,9 +53,9 @@ impl WRevoluteVelocityConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
 
@@ -262,9 +262,9 @@ impl WRevoluteVelocityGroundConstraint {
         let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
         let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
         let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
-        let im2 = SimdReal::from(array![|ii| rbs2[ii].mass_properties.inv_mass; SIMD_WIDTH]);
+        let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
         let ii2_sqrt = AngularInertia::<SimdReal>::from(
-            array![|ii| rbs2[ii].world_inv_inertia_sqrt; SIMD_WIDTH],
+            array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
         );
         let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
         let impulse = Vector5::from(array![|ii| cparams[ii].impulse; SIMD_WIDTH]);
diff --git a/src/dynamics/solver/parallel_island_solver.rs b/src/dynamics/solver/parallel_island_solver.rs
index 9a02330..389b6e6 100644
--- a/src/dynamics/solver/parallel_island_solver.rs
+++ b/src/dynamics/solver/parallel_island_solver.rs
@@ -250,7 +250,7 @@ impl ParallelIslandSolver {
                         let rb = &mut bodies[handle.0];
                         let dvel = mj_lambdas[rb.active_set_offset];
                         rb.linvel += dvel.linear;
-                        rb.angvel += rb.world_inv_inertia_sqrt.transform_vector(dvel.angular);
+                        rb.angvel += rb.effective_world_inv_inertia_sqrt.transform_vector(dvel.angular);
                         rb.integrate(params.dt());