diff --git a/Environment/SlidingPlanarExponential.h b/Environment/SlidingPlanarExponential.h
index c04c084ec5775f4307004a907c065c9761bb57b5..573d2de7e68bcd723778a242972047c3dd316578 100644
--- a/Environment/SlidingPlanarExponential.h
+++ b/Environment/SlidingPlanarExponential.h
@@ -54,16 +54,14 @@ namespace corsika::environment {
     corsika::units::si::GrammageType IntegratedGrammage(
         corsika::geometry::Trajectory<corsika::geometry::Line> const& line,
         corsika::units::si::LengthType pTo) const override {
-      feenableexcept(FE_INVALID);
-      auto const axis = (Base::fP0 - line.GetR0()).normalized();
+      auto const axis = (line.GetR0() - Base::fP0).normalized();
       return Base::IntegratedGrammage(line, pTo, axis);
     }
 
     corsika::units::si::LengthType ArclengthFromGrammage(
         corsika::geometry::Trajectory<corsika::geometry::Line> const& line,
         corsika::units::si::GrammageType pGrammage) const override {
-      feenableexcept(FE_INVALID);
-      auto const axis = (Base::fP0 - line.GetR0()).normalized();
+      auto const axis = (line.GetR0() - Base::fP0).normalized();
       return Base::ArclengthFromGrammage(line, pGrammage, axis);
     }
   };