correct transform was -y direction

src/renderer.cpp

@@ -240,7 +240,7 @@ Vector3 sim_to_render(Vec3 pos, double scale) {
     return (Vector3){
         (float)(pos.x * scale),
         (float)(pos.z * scale),
-        (float)(pos.y * scale)
+        (float)(-pos.y * scale)
     };
 }