diff --git a/src/meas.rs b/src/meas.rs
index 75cb206..ca33bea 100644
--- a/src/meas.rs
+++ b/src/meas.rs
@@ -40,7 +40,7 @@ pub struct Current(pub u32, pub u32);
 impl AbstractMeasurement for Current {
     fn eval(&self, state: &SimSnapshot) -> String {
         let current = state.get(self.0, self.1).current();
-        format!("current({}, {}): ({:.2e}, {:.2e})", self.0, self.1, current.x, current.y)
+        format!("current({}, {}): ({:.2e}, {:.2e}, {:.2e})", self.0, self.1, current.x(), current.y(), current.z())
     }
 }
 
diff --git a/src/render.rs b/src/render.rs
index 6516ef3..b5c1cd7 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -106,11 +106,11 @@ impl<'a> RenderSteps<'a> {
         }
     }
     fn render_e_field(&mut self) {
-        self.render_vector_field(Rgb([0xff, 0xff, 0xff]), 100.0, |cell| cell.e());
+        self.render_vector_field(Rgb([0xff, 0xff, 0xff]), 100.0, |cell| cell.e().xy());
         // current
         self.render_vector_field(Rgb([0x00, 0xa0, 0x30]), 1.0e-12, |cell| {
             //if cell.mat().conductivity() >= 1.0e3 {
-                cell.e()*cell.mat().conductivity()
+                cell.e().xy()*cell.mat().conductivity()
             //} else {
             //    Default::default()
             //}
diff --git a/src/sim.rs b/src/sim.rs
index 1b4b47c..68f89c2 100644
--- a/src/sim.rs
+++ b/src/sim.rs
@@ -125,6 +125,9 @@ impl<M> SimState<M> {
     pub fn impulse_ey(&mut self, x: u32, y: u32, ey: Flt) {
         self.get_mut(x, y).state.e += Vec3::new(0.0, ey, 0.0);
     }
+    pub fn impulse_ez(&mut self, x: u32, y: u32, ez: Flt) {
+        self.get_mut(x, y).state.e += Vec3::new(0.0, 0.0, ez);
+    }
 
     pub fn width(&self) -> u32 {
         self.cells.shape()[1] as _
@@ -178,8 +181,8 @@ impl<M> Cell<M> {
     pub fn ez(&self) -> Flt {
         self.state.e().z()
     }
-    pub fn e(&self) -> Point {
-        Point::new(self.ex(), self.ey())
+    pub fn e(&self) -> Vec3 {
+        self.state.e()
     }
     pub fn hx(&self) -> Flt {
         self.state.h().x()
@@ -209,9 +212,9 @@ impl<M: Material> Cell<M> {
         self.b().z()
     }
 
-    pub fn current(&self) -> Point {
+    pub fn current(&self) -> Vec3 {
         let conductivity = self.mat.conductivity();
-        Point::new(self.ex()*conductivity, self.ey()*conductivity)
+        self.e()*conductivity
     }
 
     fn impulse_bz(&mut self, delta_bz: Flt) {
diff --git a/src/vec3.rs b/src/vec3.rs
index ad06979..f0dcc9c 100644
--- a/src/vec3.rs
+++ b/src/vec3.rs
@@ -1,4 +1,5 @@
 use crate::flt::{Flt, Real};
+use crate::geom::Point;
 use std::convert::From;
 use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub};
 
@@ -32,6 +33,9 @@ impl Vec3 {
     pub fn z(&self) -> Flt {
         self.z.into()
     }
+    pub fn xy(&self) -> Point {
+        Point::new(self.x(), self.y())
+    }
 }
 
 impl From<(Real, Real, Real)> for Vec3 {
@@ -96,6 +100,23 @@ impl Mul<Real> for Vec3 {
     }
 }
 
+impl MulAssign<Flt> for Vec3 {
+    fn mul_assign(&mut self, other: Flt) {
+        self.x *= other;
+        self.y *= other;
+        self.z *= other;
+    }
+}
+
+impl Mul<Flt> for Vec3 {
+    type Output = Self;
+    fn mul(self, other: Flt) -> Self {
+        let mut work = self.clone();
+        work *= other;
+        work
+    }
+}
+
 impl DivAssign<Real> for Vec3 {
     fn div_assign(&mut self, other: Real) {
         *self *= Real::from_inner(1.0) / other;
@@ -110,3 +131,18 @@ impl Div<Real> for Vec3 {
         work
     }
 }
+
+impl DivAssign<Flt> for Vec3 {
+    fn div_assign(&mut self, other: Flt) {
+        *self *= (1.0 / other);
+    }
+}
+
+impl Div<Flt> for Vec3 {
+    type Output = Self;
+    fn div(self, other: Flt) -> Self {
+        let mut work = self.clone();
+        work /= other;
+        work
+    }
+}