diff --git a/src/model_physics.rs b/src/model_physics.rs
index 8063d30..b0021eb 100644
--- a/src/model_physics.rs
+++ b/src/model_physics.rs
@@ -354,22 +354,26 @@ impl MinkowskiMesh<'_>{
 		MinkowskiVert::VertVert(self.mesh0.farthest_vert(dir),self.mesh1.farthest_vert(-dir))
 	}
 	pub fn predict_collision_in(&self,relative_body:&crate::physics::Body,time_limit:crate::integer::Time)->Option<(MinkowskiFace,crate::integer::Time)>{
-		let start_vert=FEV::<MinkowskiFace,MinkowskiDirectedEdge,MinkowskiVert>::Vert(self.farthest_vert((-relative_body.clone()).infinity_dir()));
-		match crate::face_crawler::crawl_fev_from_negative_infinity(start_vert,self,relative_body,relative_body.time){
-			crate::face_crawler::CrawlResult::Closest(fev)=>{
-				crate::face_crawler::crawl_fev(fev,self,relative_body,relative_body.time,time_limit)
-			},
-			crate::face_crawler::CrawlResult::Hit(_,_)=>None,//already in or passed
-		}
+		(-relative_body.clone()).infinity_dir().map_or(None,|dir|{
+			let start_vert=FEV::<MinkowskiFace,MinkowskiDirectedEdge,MinkowskiVert>::Vert(self.farthest_vert(dir));
+			match crate::face_crawler::crawl_fev_from_negative_infinity(start_vert,self,relative_body,relative_body.time){
+				crate::face_crawler::CrawlResult::Closest(fev)=>{
+					crate::face_crawler::crawl_fev(fev,self,relative_body,relative_body.time,time_limit)
+				},
+				crate::face_crawler::CrawlResult::Hit(_,_)=>None,//already in or passed
+			}
+		})
 	}
 	pub fn predict_collision_out(&self,relative_body:&crate::physics::Body,time_limit:crate::integer::Time)->Option<(MinkowskiFace,crate::integer::Time)>{
-		let start_vert=FEV::<MinkowskiFace,MinkowskiDirectedEdge,MinkowskiVert>::Vert(self.farthest_vert(relative_body.infinity_dir()));
-		match crate::face_crawler::crawl_fev_from_negative_infinity(start_vert,self,&-relative_body.clone(),-time_limit){
-			crate::face_crawler::CrawlResult::Closest(fev)=>{
-				crate::face_crawler::crawl_fev(fev,self,&-relative_body.clone(),-time_limit,-relative_body.time).map(|t|(t.0,-t.1))
-			},
-			crate::face_crawler::CrawlResult::Hit(face,time)=>Some((face,-time)),
-		}
+		relative_body.infinity_dir().map_or(None,|dir|{
+			let start_vert=FEV::<MinkowskiFace,MinkowskiDirectedEdge,MinkowskiVert>::Vert(self.farthest_vert(dir));
+			match crate::face_crawler::crawl_fev_from_negative_infinity(start_vert,self,&-relative_body.clone(),-time_limit){
+				crate::face_crawler::CrawlResult::Closest(fev)=>{
+					crate::face_crawler::crawl_fev(fev,self,&-relative_body.clone(),-time_limit,-relative_body.time).map(|t|(t.0,-t.1))
+				},
+				crate::face_crawler::CrawlResult::Hit(face,time)=>Some((face,-time)),
+			}
+		})
 	}
 	pub fn predict_collision_face_out(&self,relative_body:&crate::physics::Body,time_limit:crate::integer::Time,contact_face_id:MinkowskiFace)->Option<(MinkowskiEdge,crate::integer::Time)>{
 		//no algorithm needed, there is only one state and two cases (Edge,None)
diff --git a/src/physics.rs b/src/physics.rs
index 7bd8aa8..d8baefa 100644
--- a/src/physics.rs
+++ b/src/physics.rs
@@ -968,11 +968,15 @@ impl Body{
 		self.velocity=self.extrapolated_velocity(time);
 		self.time=time;
 	}
-	pub fn infinity_dir(&self)->Planar64Vec3{
+	pub fn infinity_dir(&self)->Option<Planar64Vec3>{
 		if self.acceleration==Planar64Vec3::ZERO{
-			self.velocity
+			if self.velocity==Planar64Vec3::ZERO{
+				None
+			}else{
+				Some(self.velocity)
+			}
 		}else{
-			self.acceleration
+			Some(self.acceleration)
 		}
 	}
 }