From Magnus Kessler, "At the end of the void function

osg::Animation::TemplateStepInterpolator::getValue the code tries to return
the result rather than assigning it to the result parameter reference.

The following patch fixes this."

include/osgAnimation/Interpolator

@@ -85,7 +85,7 @@ namespace osgAnimation
             }
 
             int i = getKeyIndexFromTime(keyframes,time);
-            return keyframes[i].getValue();
+            result = keyframes[i].getValue();
         }
     };