diff --git a/src/commands.rs b/src/commands.rs
index f102c72..48020e6 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -61,7 +61,7 @@ struct ParserState {
     warmup_seconds: f32,
     engine_type: actor::EngineType,
     oxygen: f32,
-    mass: f64,
+    density: f64,
     collider: Collider,
     camdistance: f32,
     suit_integrity: f32,
@@ -116,7 +116,7 @@ impl Default for ParserState {
             warmup_seconds: default_engine.warmup_seconds,
             engine_type: default_engine.engine_type,
             oxygen: nature::OXY_D,
-            mass: 1.0,
+            density: 100.0,
             collider: Collider::sphere(1.0),
             camdistance: default_actor.camdistance,
             suit_integrity: 1.0,
@@ -373,9 +373,9 @@ pub fn load_defs(
                     continue;
                 }
             }
-            ["mass", value] => {
+            ["density", value] => {
                 if let Ok(value_float) = value.parse::<f64>() {
-                    state.mass = value_float;
+                    state.density = value_float;
                 }
                 else {
                     error!("Can't parse float: {line}");
@@ -621,11 +621,10 @@ fn spawn_entities(
 
             // Physics Parameters
             if state.has_physics {
-                let fix_scale: f64 = 1.0 / (state.model_scale as f64).powf(3.0);
                 actor.insert(RigidBody::Dynamic);
                 actor.insert(LinearVelocity(state.velocity));
                 actor.insert(AngularVelocity(state.angular_momentum));
-                actor.insert(ColliderDensity((state.mass * fix_scale) as f64));
+                actor.insert(ColliderDensity(state.density));
                 if state.collider_is_mesh {
                     actor.insert(AsyncSceneCollider::new(Some(
                         ComputedCollider::TriMesh
diff --git a/src/defs.txt b/src/defs.txt
index 5f1eace..a4c2b97 100644
--- a/src/defs.txt
+++ b/src/defs.txt
@@ -13,13 +13,12 @@ actor 0 593051 0 suit
     orbit 226000e3 0.66
     player yes
     id player
-    mass 200.0
-    scale 1
+    scale 2
     oxygen 0.008
     health 0.3
     angularmomentum 0 0 0
-    collider capsule 2 1
-    thrust 1.2 1 1 300 1.5
+    collider capsule 1 0.5
+    thrust 1.2 1 1 400 1.5
     rotationy 0.65
     engine monopropellant
 
@@ -28,11 +27,11 @@ actor 10 -30 20 MeteorAceGT
     relativeto player
     scale 5
     vehicle yes
-    thrust 24.5 4.8 3.3 200000 3
+    thrust 24.5 4.8 3.3 500000 3
     engine ion
-    collider sphere 1.5
+    collider sphere 1
     camdistance 50
-    mass 3000
+    density 200
     angularmomentum 0.1 0.1 0.3
 
 actor 0 0 0 io
@@ -85,14 +84,12 @@ actor 0 0 0 moonlet
     id thebe
     orbit 221900e3 0.66
     scale 50e3
-    mass 430e15
     angularmomentum 0 0.025 0
 
 actor 3000 0 0 moonlet
     name Moonlet
     relativeto player
     scale 500
-    mass 10000000
     angularmomentum 0 0.15 0
 
 actor -200 -110 1000 satellite
@@ -105,13 +102,13 @@ actor -200 -110 1000 satellite
     collider capsule 7.5 1
     rotationy 0.5
     angularmomentum 0 0 0
-    mass 10
+    density 0.01
 
 actor 1000 20 300 monolith
     name "Mysterious Monolith 1"
     relativeto player
     scale 2
-    mass 1000
+    density 300
     rotationx 0.5
     wants maxrotation 0.01
     angularmomentum 0.0 0.0 0.01
@@ -121,7 +118,7 @@ actor 10000 2000 -3500 monolith
     name "Mysterious Monolith 2"
     relativeto player
     scale 2
-    mass 1000
+    density 300
     rotationx 0.5
     wants maxrotation 0.01
     angularmomentum 0.0 0.0 0.01
@@ -131,7 +128,7 @@ actor -8000 -1000 -100 monolith
     name "Mysterious Monolith 3"
     relativeto player
     scale 2
-    mass 1000
+    density 300
     rotationx 0.5
     wants maxrotation 0.01
     angularmomentum 0.0 0.0 0.01
@@ -142,7 +139,6 @@ actor -3300 10 0 pizzeria
     relativeto player
     id pizzeria
     scale 40
-    mass 1000000
     rotationy 0.30
     angularmomentum 0 0 0
     actor -120 0 20 MeteorAceGT
@@ -154,13 +150,13 @@ actor -3300 10 0 pizzeria
         engine ion
         collider sphere 1.5
         camdistance 50
-        mass 3000
+        density 200
         angularmomentum 0 0 0.2
     actor -100 63 -13 pizzasign
         name "Pizzeria Sign"
         relativeto pizzeria
         scale 20
-        mass 200
+        density 200
         rotationy 0.45
         angularmomentum 0 0 0
     actor -16 -10 0 lightorb
@@ -193,8 +189,8 @@ actor -3300 10 0 pizzeria
         name "Space Pizza™"
         chatid pizzeria
         alive yes
-        mass 200.0
-        collider capsule 2 1
+        scale 2
+        collider capsule 1 0.5
         thrust 1.2 1 1 10 1.5
         wants maxrotation 0
         wants maxvelocity 0
@@ -251,8 +247,8 @@ actor 60 -15 -40 suit
     name Icarus
     chatid hi_icarus
     alive yes
-    mass 200.0
-    collider capsule 2 1
+    scale 2
+    collider capsule 1 0.5
     angularmomentum 0.4 0.2 0.1
     rotationy 0.6
     rotationx 1
@@ -351,8 +347,8 @@ actor -300 0 40 suit
     name "Drifter"
     chatid drifter
     oxygen 0.08
-    mass 200.0
-    collider capsule 2 1
+    scale 2
+    collider capsule 1 0.5
     chat drifter
         name "Drifter"
         msg 2 INIT dead "Error: No response"