diff --git a/src/Mod/PartDesign/App/FeatureSketchBased.cpp b/src/Mod/PartDesign/App/FeatureSketchBased.cpp
index 4904471845..a3e354d8c9 100644
--- a/src/Mod/PartDesign/App/FeatureSketchBased.cpp
+++ b/src/Mod/PartDesign/App/FeatureSketchBased.cpp
@@ -140,7 +140,7 @@ std::vector<TopoDS_Wire> SketchBased::getSketchWires() const {
 
     return result;
 }
-
+
 // TODO: This code is taken from and duplicates code in Part2DObject::positionBySupport()
 // Note: We cannot return a reference, because it will become Null.
 // Not clear where, because we check for IsNull() here, but as soon as it is passed out of
@@ -172,14 +172,14 @@ const TopoDS_Face SketchBased::getSupportFace() const {
 
     return face;
 }
-
+
 Part::Feature* SketchBased::getSupport() const {
     // get the support of the Sketch if any
     App::DocumentObject* SupportLink = static_cast<Part::Part2DObject*>(Sketch.getValue())->Support.getValue();
     Part::Feature* SupportObject = NULL;
     if (SupportLink && SupportLink->getTypeId().isDerivedFrom(Part::Feature::getClassTypeId()))
         SupportObject = static_cast<Part::Feature*>(SupportLink);
-
+
     return SupportObject;
 }
 
@@ -197,7 +197,7 @@ const TopoDS_Shape& SketchBased::getSupportShape() const {
 
     return result;
 }
-
+
 int SketchBased::getSketchAxisCount(void) const
 {
     Part::Part2DObject *sketch = static_cast<Part::Part2DObject*>(Sketch.getValue());
@@ -484,12 +484,13 @@ void SketchBased::generatePrism(TopoDS_Shape& prism,
             // Note: 1E6 created problems once...
             Ltotal = 1E4;
 
-        if (midplane)
-            Loffset = -Ltotal/2;
-        else if (method == "TwoLengths") {
+
+        if (method == "TwoLengths") {
+            // midplane makes no sense here
             Loffset = -L2;
             Ltotal += L2;
-        }
+        } else if (midplane)
+            Loffset = -Ltotal/2;
 
         TopoDS_Shape from = sketchshape;
         if (method == "TwoLengths" || midplane) {