diff --git a/src/args.rs b/src/args.rs
index 42084065cf..034f40fce1 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -14,6 +14,10 @@ pub struct Args {
     /// Parameters for the model, each in the form `key=value`
     #[clap(short, long)]
     pub parameters: Vec<String>,
+
+    // Model deviation tolerance
+    #[clap[short, long, default_value = "0.0"]]
+    pub tolerance: f64,
 }
 
 impl Args {
diff --git a/src/main.rs b/src/main.rs
index da88179ea6..e3a705d206 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -81,22 +81,27 @@ fn main() -> anyhow::Result<()> {
 
     let mut aabb = shape.bounding_volume();
 
-    // Compute a reasonable default for the tolerance value. To do this, we just
-    // look at the smallest non-zero extent of the bounding box and divide that
-    // by some value.
-    let tolerance = {
-        let mut min_extent = Scalar::MAX;
-        for extent in aabb.size().components() {
-            if extent > Scalar::ZERO && extent < min_extent {
-                min_extent = extent;
+    let user_defined_tolerance = Scalar::from_f64(args.tolerance);
+
+    let tolerance = match user_defined_tolerance {
+        m if m <= Scalar::ZERO => {
+            // Compute a reasonable default for the tolerance value. To do this, we just
+            // look at the smallest non-zero extent of the bounding box and divide that
+            // by some value.
+            let mut min_extent = Scalar::MAX;
+            for extent in aabb.size().components() {
+                if extent > Scalar::ZERO && extent < min_extent {
+                    min_extent = extent;
+                }
             }
-        }
 
-        // `tolerance` must not be zero, or we'll run into trouble.
-        let tolerance = min_extent / Scalar::from_f64(1000.);
-        assert!(tolerance > Scalar::ZERO);
+            // `tolerance` must not be zero, or we'll run into trouble.
+            let tolerance = min_extent / Scalar::from_f64(1000.);
+            assert!(tolerance > Scalar::ZERO);
 
-        tolerance
+            tolerance
+        }
+        _ => user_defined_tolerance,
     };
 
     let mut debug_info = DebugInfo::new();