diff --git a/src/gameplay_style.rs b/src/gameplay_style.rs
index b619294..7ac1c9f 100644
--- a/src/gameplay_style.rs
+++ b/src/gameplay_style.rs
@@ -170,10 +170,17 @@ pub struct StrafeSettings{
 	tick_rate:Ratio64,
 }
 impl StrafeSettings{
+	pub fn tick_velocity(&self,velocity:Planar64Vec3,control_dir:Planar64Vec3)->Option<Planar64Vec3>{
+		let d=velocity.dot(control_dir);
+		match d<self.mv{
+			true=>Some(velocity+control_dir*self.air_accel_limit.map_or(self.mv-d,|limit|limit.min(self.mv-d))),
+			false=>None,
+		}
+	}
 	pub fn next_tick(&self,time:Time)->Time{
 		Time::from_nanos(self.tick_rate.rhs_div_int(self.tick_rate.mul_int(time.nanos())+1))
 	}
-	pub fn allow_strafe(&self,controls:Controls)->bool{
+	pub const fn allow_strafe(&self,controls:Controls)->bool{
 		self.enable.activates(controls)
 	}
 }
@@ -184,9 +191,12 @@ pub struct PropulsionSettings{
 	magnitude:Planar64,
 }
 impl PropulsionSettings{
-	pub fn activates(&self,controls:Controls)->bool{
+	pub const fn activates(&self,controls:Controls)->bool{
 		self.enable.activates(controls)
 	}
+	pub fn acceleration(&self,control_dir:Planar64Vec3)->Planar64Vec3{
+		control_dir*self.magnitude
+	}
 }
 
 #[derive(Clone)]
diff --git a/src/integer.rs b/src/integer.rs
index 844cf4e..9bf91c6 100644
--- a/src/integer.rs
+++ b/src/integer.rs
@@ -91,7 +91,7 @@ const fn gcd(mut a:u64,mut b:u64)->u64{
 	};
 	a
 }
-#[derive(Clone,Hash)]
+#[derive(Clone,Copy,Hash)]
 pub struct Ratio64{
 	num:i64,
 	den:u64,
@@ -109,15 +109,15 @@ impl Ratio64{
 		}
 	}
 	#[inline]
-	pub fn mul_int(&self,rhs:i64)->i64{
+	pub const fn mul_int(&self,rhs:i64)->i64{
 		rhs*self.num/(self.den as i64)
 	}
 	#[inline]
-	pub fn rhs_div_int(&self,rhs:i64)->i64{
+	pub const fn rhs_div_int(&self,rhs:i64)->i64{
 		rhs*(self.den as i64)/self.num
 	}
 	#[inline]
-	pub fn mul_ref(&self,rhs:&Ratio64)->Ratio64{
+	pub const fn mul_ref(&self,rhs:&Ratio64)->Ratio64{
 		let (num,den)=(self.num*rhs.num,self.den*rhs.den);
 		let d=gcd(num.unsigned_abs(),den);
 		Self{
@@ -259,7 +259,7 @@ impl std::ops::Div<u64> for Ratio64{
 		}
 	}
 }
-#[derive(Clone,Hash)]
+#[derive(Clone,Copy,Hash)]
 pub struct Ratio64Vec2{
 	pub x:Ratio64,
 	pub y:Ratio64,
@@ -267,11 +267,11 @@ pub struct Ratio64Vec2{
 impl Ratio64Vec2{
 	pub const ONE:Self=Self{x:Ratio64::ONE,y:Ratio64::ONE};
 	#[inline]
-	pub fn new(x:Ratio64,y:Ratio64)->Self{
+	pub const fn new(x:Ratio64,y:Ratio64)->Self{
 		Self{x,y}
 	}
 	#[inline]
-	pub fn mul_int(&self,rhs:glam::I64Vec2)->glam::I64Vec2{
+	pub const fn mul_int(&self,rhs:glam::I64Vec2)->glam::I64Vec2{
 		glam::i64vec2(
 			self.x.mul_int(rhs.x),
 			self.y.mul_int(rhs.y),
@@ -846,7 +846,7 @@ impl Default for Planar64Mat3{
 }
 impl Planar64Mat3{
 	#[inline]
-	pub fn from_cols(x_axis:Planar64Vec3,y_axis:Planar64Vec3,z_axis:Planar64Vec3)->Self{
+	pub const fn from_cols(x_axis:Planar64Vec3,y_axis:Planar64Vec3,z_axis:Planar64Vec3)->Self{
 		Self{
 			x_axis,
 			y_axis,