diff --git a/src/main/scala/li/cil/oc/server/component/MotionSensor.scala b/src/main/scala/li/cil/oc/server/component/MotionSensor.scala
index 47b1d048f..399763223 100644
--- a/src/main/scala/li/cil/oc/server/component/MotionSensor.scala
+++ b/src/main/scala/li/cil/oc/server/component/MotionSensor.scala
@@ -102,18 +102,15 @@ class MotionSensor(val host: EnvironmentHost) extends prefab.AbstractManagedEnvi
       // is pseudo-infrared driven (it only works for *living* entities, after
       // all), so I think it makes more sense for it to work in the dark, too.
       /* entity.getBrightness(0) > 0.2 && */ {
-      var ox = x + 0.5
-      var oy = y + 0.5
-      var oz = z + 0.5
+      var origin = new Vec3d(x, y, z)
       val target = new Vec3d(entity.posX, entity.posY, entity.posZ)
-      // Start trace outside of this block.
-      if (entity.posX < x) ox -= 0.75
-      if (entity.posX > x + 1) ox += 0.75
-      if (entity.posY < y) oy -= 0.75
-      if (entity.posY > y + 1) oy += 0.75
-      if (entity.posZ < z) oz -= 0.75
-      if (entity.posZ > z + 1) oz += 0.75
-      world.rayTraceBlocks(new Vec3d(ox, oy, oz), target) == null
+      val path = origin.subtract(target).normalize()
+      origin = origin.addVector(
+        path.xCoord * 0.75,
+        path.yCoord * 0.75,
+        path.zCoord * 0.75
+      )
+      world.rayTraceBlocks(origin, target) == null
     }
 
   private def sendSignal(entity: EntityLivingBase) {