diff --git a/osi_motionrequest.proto b/osi_motionrequest.proto
index 872b0d2d5..0c78d0ab1 100644
--- a/osi_motionrequest.proto
+++ b/osi_motionrequest.proto
@@ -17,33 +17,20 @@ package osi3;
 //
 message MotionRequest
 {
+	oneof motion_request
+	{
+		//
+		// Defines a desired state.
+		// If the output option is set to DESIRED_STATE this must be provided.
+		//
+		DesiredState desired_state = 1;
 
-	//	
-	// Define different options for had function ouput.
-	// Each option is corresponds to a field in the message.
-	//
-	enum OutputOptions {
-		DESIRED_STATE = 0;
-		TRAJECTORY = 1;
+		//
+		// Defines a desired trajectory.
+		// If the output option is set to DESIRED_TRAJECTORY this must be set.
+		//
+		Trajectory desired_trajectory = 2;
 	}
-    
-	//
-	// Define the option that is used to specify the motion request.
-	// This must be set. Additionaly the field corresponding to the specified option must be set.
-	//
-        optional OutputOptions output_option = 1;
-	
-	//
-	// Defines a desired state.
-	// If the output option is set to DESIRED_STATE this must be provided.
-	//
-	optional DesiredState desired_state = 2;
-	
-	//
-	// Defines a desired trajectory.
-	// If the output option is set to DESIRED_TRAJECTORY this must be set.
-	//
-	optional Trajectory desired_trajectory = 3;
 }
 
 //
@@ -51,7 +38,8 @@ message MotionRequest
 // in the HAD function. The task of the acutator management is to follow the trajectory as close as possible.
 // The timestamps inside the trajecotry must be defined in global simulation time.
 //
-message Trajectory {
+message Trajectory
+{
 	repeated StatePoint trajectory_point = 1;
 }