diff --git a/geo/Triangle3.h b/geo/Triangle3.h
index f86c4b4..ca09888 100644
--- a/geo/Triangle3.h
+++ b/geo/Triangle3.h
@@ -136,6 +136,14 @@ public:
 
 	}
 
+	/** perform some sanity checks */
+	bool isValid() const {
+		if (p1 == p2) {return false;}
+		if (p1 == p3) {return false;}
+		if (p2 == p3) {return false;}
+		return true;
+	}
+
 /*
 	int rayIntersectsTriangle(float *p, float *d,
 				float *v0, float *v1, float *v2) {
diff --git a/wifi/estimate/ray3/ModelFactory.h b/wifi/estimate/ray3/ModelFactory.h
index 234c433..adbe864 100644
--- a/wifi/estimate/ray3/ModelFactory.h
+++ b/wifi/estimate/ray3/ModelFactory.h
@@ -339,6 +339,13 @@ namespace Ray3D {
 
 			const std::string& name = foo->file;
 			Obstacle3D obs = OBJPool::get().getObject(name);
+
+			// perform sanity checks
+			if (!obs.isValid()) {
+				throw std::runtime_error("invalid obstacle-data detected");
+			}
+
+			// apply scaling/rotation/translation
 			obs = obs.scaled(foo->scale);
 			obs = obs.rotated_deg( Point3(foo->rot.x, foo->rot.y, foo->rot.z) );
 			obs = obs.translated(foo->pos + Point3(0,0,fpos.z1));
diff --git a/wifi/estimate/ray3/Obstacle3.h b/wifi/estimate/ray3/Obstacle3.h
index ff84594..cfbfc71 100644
--- a/wifi/estimate/ray3/Obstacle3.h
+++ b/wifi/estimate/ray3/Obstacle3.h
@@ -89,6 +89,14 @@ namespace Ray3D {
 			return res;
 		}
 
+		/** perform sanity checks */
+		bool isValid() const {
+			for (const Triangle3& t : triangles) {
+				if (!t.isValid()) {return false;}
+			}
+			return true;
+		}
+
 	};
 
 }