diff --git a/src/phys.c b/src/phys.c
index 38f9af9a..6bec2c4f 100644
--- a/src/phys.c
+++ b/src/phys.c
@@ -53,7 +53,7 @@ struct phys_collision_data_array phys_create_and_update_contacts(struct arena *a
 
     for (u64 check0_index = 0; check0_index < ss->num_ents_reserved; ++check0_index) {
         struct sim_ent *check0 = &ss->ents[check0_index];
-        if (!sim_ent_should_simulate(check0)) continue;
+        if (!sim_ent_is_valid_and_active(check0)) continue;
         if (!(sim_ent_has_prop(check0, SIM_ENT_PROP_PHYSICAL_DYNAMIC) || sim_ent_has_prop(check0, SIM_ENT_PROP_PHYSICAL_KINEMATIC))) continue;
         if (check0->local_collider.count <= 0) continue;
 
@@ -66,7 +66,7 @@ struct phys_collision_data_array phys_create_and_update_contacts(struct arena *a
         while ((space_entry = space_iter_next(&iter))) {
             struct sim_ent *check1 = sim_ent_from_id(ss, space_entry->ent);
             if (check1 == check0) continue;
-            if (!sim_ent_should_simulate(check1)) continue;
+            if (!sim_ent_is_valid_and_active(check1)) continue;
             if (!(sim_ent_has_prop(check1, SIM_ENT_PROP_PHYSICAL_DYNAMIC) || sim_ent_has_prop(check1, SIM_ENT_PROP_PHYSICAL_KINEMATIC))) continue;
             if (check1->local_collider.count <= 0) continue;
 
@@ -274,7 +274,7 @@ void phys_prepare_contacts(struct phys_step_ctx *ctx, u64 phys_iteration)
 
     for (u64 sim_ent_index = 0; sim_ent_index < ss->num_ents_reserved; ++sim_ent_index) {
         struct sim_ent *constraint_ent = &ss->ents[sim_ent_index];
-        if (!sim_ent_should_simulate(constraint_ent)) continue;
+        if (!sim_ent_is_valid_and_active(constraint_ent)) continue;
         if (!sim_ent_has_prop(constraint_ent, SIM_ENT_PROP_CONTACT_CONSTRAINT)) continue;
 
         struct phys_contact_constraint *constraint = &constraint_ent->contact_constraint_data;
@@ -282,7 +282,7 @@ void phys_prepare_contacts(struct phys_step_ctx *ctx, u64 phys_iteration)
         u32 num_points = constraint->num_points;
         struct sim_ent *e0 = sim_ent_from_id(ss, constraint->e0);
         struct sim_ent *e1 = sim_ent_from_id(ss, constraint->e1);
-        if (constraint->last_phys_iteration >= phys_iteration && num_points > 0 && sim_ent_should_simulate(e0) && sim_ent_should_simulate(e1)) {
+        if (constraint->last_phys_iteration >= phys_iteration && num_points > 0 && sim_ent_is_valid_and_active(e0) && sim_ent_is_valid_and_active(e1)) {
             struct v2 normal = constraint->normal;
             struct v2 tangent = v2_perp(normal);
 
@@ -296,12 +296,26 @@ void phys_prepare_contacts(struct phys_step_ctx *ctx, u64 phys_iteration)
             f32 inv_i0;
             f32 inv_i1;
             {
-                f32 scale0 = math_fabs(xform_get_determinant(e0_xf));
-                f32 scale1 = math_fabs(xform_get_determinant(e1_xf));
-                inv_m0 = 1.f / (e0->mass_unscaled * scale0);
-                inv_m1 = 1.f / (e1->mass_unscaled * scale1);
-                inv_i0 = 1.f / (e0->inertia_unscaled * scale0);
-                inv_i1 = 1.f / (e1->inertia_unscaled * scale1);
+                if (sim_ent_should_simulate(e0)) {
+                    f32 scale0 = math_fabs(xform_get_determinant(e0_xf));
+                    inv_m0 = 1.f / (e0->mass_unscaled * scale0);
+                    inv_i0 = 1.f / (e0->inertia_unscaled * scale0);
+                } else {
+                    /* e0 is not simulated locally, pretend it has infinite mass for this contact */
+                    inv_m0 = 0;
+                    inv_i0 = 0;
+                }
+
+                if (sim_ent_should_simulate(e1)) {
+                    f32 scale1 = math_fabs(xform_get_determinant(e1_xf));
+                    inv_m1 = 1.f / (e1->mass_unscaled * scale1);
+                    inv_i1 = 1.f / (e1->inertia_unscaled * scale1);
+                } else {
+                    /* e0 is not simulated locally, pretend it has infinite mass for this contact */
+                    inv_m1 = 0;
+                    inv_i1 = 0;
+                }
+
             }
             constraint->inv_m0 = inv_m0;
             constraint->inv_m1 = inv_m1;
@@ -392,7 +406,7 @@ void phys_warm_start_contacts(struct phys_step_ctx *ctx)
     struct sim_snapshot *ss = ctx->sim_step_ctx->world;
     for (u64 sim_ent_index = 0; sim_ent_index < ss->num_ents_reserved; ++sim_ent_index) {
         struct sim_ent *constraint_ent = &ss->ents[sim_ent_index];
-        if (!sim_ent_should_simulate(constraint_ent)) continue;
+        if (!sim_ent_is_valid_and_active(constraint_ent)) continue;
         if (!sim_ent_has_prop(constraint_ent, SIM_ENT_PROP_CONTACT_CONSTRAINT)) continue;
 
         struct phys_contact_constraint *constraint = &constraint_ent->contact_constraint_data;
@@ -401,7 +415,7 @@ void phys_warm_start_contacts(struct phys_step_ctx *ctx)
         struct sim_ent *e0 = sim_ent_from_id(ss, constraint->e0);
         struct sim_ent *e1 = sim_ent_from_id(ss, constraint->e1);
 
-        if (num_points > 0 && sim_ent_should_simulate(e0) && sim_ent_should_simulate(e1) && !constraint->skip_solve) {
+        if (num_points > 0 && sim_ent_is_valid_and_active(e0) && sim_ent_is_valid_and_active(e1) && !constraint->skip_solve) {
             struct xform e0_xf = sim_ent_get_xform(e0);
             struct xform e1_xf = sim_ent_get_xform(e1);
 
@@ -447,7 +461,7 @@ void phys_solve_contacts(struct phys_step_ctx *ctx, f32 dt, b32 apply_bias)
     struct sim_snapshot *ss = ctx->sim_step_ctx->world;
     for (u64 sim_ent_index = 0; sim_ent_index < ss->num_ents_reserved; ++sim_ent_index) {
         struct sim_ent *constraint_ent = &ss->ents[sim_ent_index];
-        if (!sim_ent_should_simulate(constraint_ent)) continue;
+        if (!sim_ent_is_valid_and_active(constraint_ent)) continue;
         if (!sim_ent_has_prop(constraint_ent, SIM_ENT_PROP_CONTACT_CONSTRAINT)) continue;
 
         struct phys_contact_constraint *constraint = &constraint_ent->contact_constraint_data;
@@ -461,7 +475,7 @@ void phys_solve_contacts(struct phys_step_ctx *ctx, f32 dt, b32 apply_bias)
         f32 w1 = e1->angular_velocity;
 
         u32 num_points = constraint->num_points;
-        if (num_points > 0 && sim_ent_should_simulate(e0) && sim_ent_should_simulate(e1) && !constraint->skip_solve) {
+        if (num_points > 0 && sim_ent_is_valid_and_active(e0) && sim_ent_is_valid_and_active(e1) && !constraint->skip_solve) {
             struct xform e0_xf = sim_ent_get_xform(e0);
             struct xform e1_xf = sim_ent_get_xform(e1);