diff --git a/src/object/plane.rs b/src/object/plane.rs
index 981fb5f..4d2fc83 100644
--- a/src/object/plane.rs
+++ b/src/object/plane.rs
@@ -67,7 +67,7 @@ impl Surface for Plane {
     fn intersect(&self, ray: Ray) -> Option<f32> {
 
         let d = self.normal.dot(&ray.direction);
-        if d < 1e-3 { return None; }
+        if d > -1e-3 { return None; }
 
         let t = (self.center - ray.origin).dot(&*self.normal) / d;