diff --git a/media/src/objects/Point.svelte b/media/src/objects/Point.svelte
index de895eac..d68a187e 100644
--- a/media/src/objects/Point.svelte
+++ b/media/src/objects/Point.svelte
@@ -56,8 +56,8 @@
     let tVal = $derived(t0 + tau * (t1 - t0));
     let displayTVal = $derived(tVal.toFixed(2));
 
-    let N0 = $derived(math.parse(params.n0.toString() ?? '0').evaluate());
-    let N1 = $derived(math.parse(params.n1.toString() ?? '0').evaluate());
+    let N0 = $derived(math.parse(params.n0?.toString() ?? '0').evaluate());
+    let N1 = $derived(math.parse(params.n1?.toString() ?? '0').evaluate());
 
     let last;
 
diff --git a/media/src/objects/Vector.svelte b/media/src/objects/Vector.svelte
index 31991e47..5b38c29b 100644
--- a/media/src/objects/Vector.svelte
+++ b/media/src/objects/Vector.svelte
@@ -71,8 +71,8 @@
 
     let last = null;
 
-    let N0 = $derived(math.parse(params.n0.toString() ?? '0').evaluate());
-    let N1 = $derived(math.parse(params.n1.toString() ?? '0').evaluate());
+    let N0 = $derived(math.parse(params.n0?.toString() ?? '0').evaluate());
+    let N1 = $derived(math.parse(params.n1?.toString() ?? '0').evaluate());
 
     const arrowMaterial = new THREE.MeshPhongMaterial({
         color: color,