diff --git a/src/integer.rs b/src/integer.rs
index 56c25e2..6c41595 100644
--- a/src/integer.rs
+++ b/src/integer.rs
@@ -404,11 +404,12 @@ impl TryFrom<[f32;3]> for Unit32Vec3{
 */
 
 ///[-1.0,1.0] = [-2^32,2^32]
-#[derive(Clone,Copy,Hash,Eq,Ord,PartialEq,PartialOrd)]
+#[derive(Clone,Copy,Debug,Hash,Eq,Ord,PartialEq,PartialOrd)]
 pub struct Planar64(i64);
 impl Planar64{
 	pub const ZERO:Self=Self(0);
 	pub const ONE:Self=Self(1<<32);
+	pub const FRAC_1_SQRT2:Self=Self(3_037_000_500);
 	#[inline]
 	pub const fn int(num:i32)->Self{
 		Self(Self::ONE.0*num as i64)
@@ -563,7 +564,7 @@ impl std::ops::Div<Planar64> for Planar64{
 
 
 ///[-1.0,1.0] = [-2^32,2^32]
-#[derive(Clone,Copy,Default,Hash,Eq,PartialEq)]
+#[derive(Clone,Copy,Debug,Default,Hash,Eq,PartialEq)]
 pub struct Planar64Vec3(glam::I64Vec3);
 impl Planar64Vec3{
 	pub const ZERO:Self=Planar64Vec3(glam::I64Vec3::ZERO);
@@ -629,6 +630,14 @@ impl Planar64Vec3{
 		)>>32) as i64)
 	}
 	#[inline]
+/*	pub fn cross(&self,rhs:Self)->Planar64Vec3{
+		Planar64Vec3(((
+			(self.0.x as i128)*(rhs.0.x as i128)+
+			(self.0.y as i128)*(rhs.0.y as i128)+
+			(self.0.z as i128)*(rhs.0.z as i128)
+		)>>32) as i64)
+	}*/
+	#[inline]
 	pub fn length(&self)->Planar64{
 		let radicand=(self.0.x as i128)*(self.0.x as i128)+(self.0.y as i128)*(self.0.y as i128)+(self.0.z as i128)*(self.0.z as i128);
 		Planar64(unsafe{(radicand as f64).sqrt().to_int_unchecked()})
diff --git a/src/load_roblox.rs b/src/load_roblox.rs
index 751e42d..16c58a9 100644
--- a/src/load_roblox.rs
+++ b/src/load_roblox.rs
@@ -49,6 +49,7 @@ fn get_attributes(name:&str,can_collide:bool,velocity:Planar64Vec3,force_interse
 	let mut intersecting=crate::model::IntersectingAttributes::default();
 	let mut contacting=crate::model::ContactingAttributes::default();
 	let mut force_can_collide=can_collide;
+	const GRAVITY:Planar64Vec3=Planar64Vec3::int(0,-100,0);
 	match name{
 		"Water"=>{
 			force_can_collide=false;
@@ -123,7 +124,20 @@ fn get_attributes(name:&str,can_collide:bool,velocity:Planar64Vec3,force_interse
 	}
 	//need some way to skip this
 	if velocity!=Planar64Vec3::ZERO{
-		general.booster=Some(crate::model::GameMechanicBooster::Velocity(velocity));
+		//assume all vertical boosters are targetting a height
+		let vg=velocity.dot(GRAVITY);
+		if Planar64::ZERO<=vg{
+			//weird down booster
+			general.booster=Some(crate::model::GameMechanicBooster::Velocity(velocity));
+		}else{
+			println!("set attr");
+			let gg=GRAVITY.dot(GRAVITY);
+			let height=-vg*gg.sqrt().sqrt()*Planar64::FRAC_1_SQRT2/gg;//vi/sqrt(-2*a)=d
+			let v=velocity-GRAVITY*(vg/gg);
+			//if we are adding zero SO BE IT, the check to see if the vectors are parallel is too sensitive
+			general.booster=Some(crate::model::GameMechanicBooster::Velocity(v));
+			general.trajectory=Some(crate::model::GameMechanicSetTrajectory::Height(height));
+		}
 	}
 	match force_can_collide{
 		true=>{
diff --git a/src/model.rs b/src/model.rs
index 76024c7..dd088c2 100644
--- a/src/model.rs
+++ b/src/model.rs
@@ -119,12 +119,12 @@ pub enum GameMechanicBooster{
 	Velocity(Planar64Vec3),//straight up boost velocity adds to your current velocity
 	Energy{direction:Planar64Vec3,energy:Planar64},//increase energy in direction
 }
-#[derive(Clone)]
+#[derive(Clone,Debug)]
 pub enum TrajectoryChoice{
 	HighArcLongDuration,//underhand lob at target: less horizontal speed and more air time
 	LowArcShortDuration,//overhand throw at target: more horizontal speed and less air time
 }
-#[derive(Clone)]
+#[derive(Clone,Debug)]
 pub enum GameMechanicSetTrajectory{
 	AirTime(Time),//air time (relative to gravity direction) is invariant across mass and gravity changes
 	Height(Planar64),//boost height (relative to gravity direction) is invariant across mass and gravity changes
diff --git a/src/physics.rs b/src/physics.rs
index fa7e1e5..9fb0df9 100644
--- a/src/physics.rs
+++ b/src/physics.rs
@@ -1395,13 +1395,25 @@ impl crate::instruction::InstructionConsumer<PhysicsInstruction> for PhysicsStat
 						}
 						match &general.trajectory{
 							Some(trajectory)=>{
+								println!("??? {:?}",trajectory);
 								match trajectory{
-									crate::model::GameMechanicSetTrajectory::AirTime(_) => todo!(),
-									crate::model::GameMechanicSetTrajectory::Height(_) => todo!(),
-									crate::model::GameMechanicSetTrajectory::TargetPointTime { target_point, time } => todo!(),
-									crate::model::GameMechanicSetTrajectory::TrajectoryTargetPoint { target_point, speed, trajectory_choice } => todo!(),
+									&crate::model::GameMechanicSetTrajectory::Height(height)=>{
+										//vg=sqrt(-2*gg*height)
+										println!("height booster h={}",height);
+										let vg=v.dot(self.style.gravity);
+										let gg=self.style.gravity.dot(self.style.gravity);
+										let hb=(gg.sqrt()*height*2).sqrt()*gg.sqrt();
+										println!("hb={} vg={}",hb,vg);
+										let b=self.style.gravity*((-hb-vg)/gg);
+										println!("bopo {}",b);
+										v+=b;
+									},
 									&crate::model::GameMechanicSetTrajectory::Velocity(velocity)=>v=velocity,
-									crate::model::GameMechanicSetTrajectory::DotVelocity { direction, dot } => todo!(),
+									crate::model::GameMechanicSetTrajectory::AirTime(_)
+									|crate::model::GameMechanicSetTrajectory::TargetPointTime{target_point:_,time:_}
+									|crate::model::GameMechanicSetTrajectory::TrajectoryTargetPoint{target_point:_,speed:_,trajectory_choice:_}
+									|crate::model::GameMechanicSetTrajectory::DotVelocity{direction:_,dot:_}
+									=>(),
 								}
 								self.touching.constrain_velocity(&self.models,&mut v);
 							},