diff --git a/examples/wrapped_torus.rs b/examples/wrapped_torus.rs
index 99e147e..a65571f 100644
--- a/examples/wrapped_torus.rs
+++ b/examples/wrapped_torus.rs
@@ -18,8 +18,8 @@ fn main() {
     let current_break = 0.5e-9; // time between 'set' pulse and 'clear' pulse
     let conductivity = 1.0e9;
 
-    let from_m = |m| (m/feat_size) as u32;
-    let m_to_um = |px| (px * 1e6) as u32;
+    let from_m = |m: Flt| (m/feat_size).round() as u32;
+    let m_to_um = |m: Flt| (m * 1e6).round() as u32;
     let half_width = width * 0.5;
     let half_depth = depth * 0.5;
 
@@ -76,8 +76,8 @@ fn main() {
         std::mem::size_of::<Flt>() * 8,
         *size_px,
         m_to_um(feat_size),
-        (peak_current * 1e3) as i64,
-        (current_duration * 1e12) as i64,
+        (peak_current * 1e3).round() as i64,
+        (current_duration * 1e12).round() as i64,
         m_to_um(ferro_major),
         m_to_um(ferro_minor),
         m_to_um(wire_major),
diff --git a/src/geom/units.rs b/src/geom/units.rs
index 90489e5..f554993 100644
--- a/src/geom/units.rs
+++ b/src/geom/units.rs
@@ -18,7 +18,7 @@ impl Coord for Meters {
         *self
     }
     fn to_index(&self, feature_size: Flt) -> Index {
-        Index((self.0 / feature_size).into())
+        Index((self.0 / feature_size).round().into())
     }
     fn from_meters(other: Meters, _feature_size: Flt) -> Self {
         other
diff --git a/src/geom/vec.rs b/src/geom/vec.rs
index 9a3a8d7..cf3348c 100644
--- a/src/geom/vec.rs
+++ b/src/geom/vec.rs
@@ -208,6 +208,9 @@ impl Vec3 {
             self.with_mag(1.0)
         }
     }
+    pub fn round(&self) -> Vec3 {
+        Self::new(self.x().round(), self.y().round(), self.z().round())
+    }
 }
 
 impl Into<(Flt, Flt, Flt)> for Vec3 {
diff --git a/src/meas.rs b/src/meas.rs
index eb92a54..e1186fd 100644
--- a/src/meas.rs
+++ b/src/meas.rs
@@ -300,7 +300,7 @@ impl AbstractMeasurement for Magnetization {
 
 fn loc(v: Meters) -> String {
     let (x, y, z): (Flt, Flt, Flt) = (*v * 1e6).into();
-    format!("({}, {}, {}) um", x as i32, y as i32, z as i32)
+    format!("({}, {}, {}) um", x.round() as i32, y.round() as i32, z.round() as i32)
 }
 
 /// M
diff --git a/src/render.rs b/src/render.rs
index f23e9ac..65e7a5f 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -64,7 +64,7 @@ fn im_size(state: &dyn GenericSim, max_w: u32, max_h: u32) -> (u32, u32) {
     let mut height = width * state.height() / state.width();
     if height > max_h {
         let stretch = max_h as f32 / height as f32;
-        width = (width as f32 * stretch) as _;
+        width = (width as f32 * stretch).round() as _;
         height = max_h;
     }
     (width, height)
@@ -249,8 +249,8 @@ impl ImageRenderExt for RgbImage {
     fn draw_field_arrow(&mut self, center: Vec2, rel: Vec2, color: Rgb<u8>, alpha: f32) {
         let start = (center - rel * 0.5).round();
         let end = (center + rel * 0.5).round();
-        let i_start = (start.x() as _, start.y() as _);
-        let i_end = (end.x() as _, end.y() as _);
+        let i_start = (start.x().round() as _, start.y().round() as _);
+        let i_end = (end.x().round() as _, end.y().round() as _);
         let interpolate_with_alpha = |left, right, left_weight| {
             pixelops::interpolate(left, right, left_weight*alpha)
         };