diff --git a/extern/gdt/gdt/math/mat/LinearSpace.h b/extern/gdt/gdt/math/mat/LinearSpace.h
index 5048ecb..6a5bcaa 100644
--- a/extern/gdt/gdt/math/mat/LinearSpace.h
+++ b/extern/gdt/gdt/math/mat/LinearSpace.h
@@ -277,7 +277,7 @@ namespace gdt {
   {
     const T dx0 = cross(T(one,zero,zero),N);
     const T dx1 = cross(T(zero,one,zero),N);
-    const T dx = normalize(select(dot(dx0,dx0) > dot(dx1,dx1),dx0,dx1));
+    const T dx = normalize(dot(dx0,dx0) > dot(dx1,dx1) ? dx0 : dx1);
     const T dy = normalize(cross(N,dx));
     return LinearSpace3<T>(dx,dy,N);
   }