diff --git a/Common/Context.h b/Common/Context.h
index 923ccf946c6d41fcb363224caed28d3334e2e1c8..6b886fae431cc11d8271fa312243e83efefeaeb6 100644
--- a/Common/Context.h
+++ b/Common/Context.h
@@ -115,7 +115,7 @@ class CTX {
   // clipping plane distance factor
   double clipFactor;
   // do or do not use the trackball for rotations
-  int useTrackball;
+  int useTrackball, trackballHyperbolicSheet;
   // point around which to rotate the scene
   double rotationCenter[3];
   // rotate around the center of mass instead of rotationCenter[]
diff --git a/Common/DefaultOptions.h b/Common/DefaultOptions.h
index 746fc053015573b12acb295fae3b82c15a9194fb..c07a907a18134d38a00de72774fcc3c61509eefa 100644
--- a/Common/DefaultOptions.h
+++ b/Common/DefaultOptions.h
@@ -844,6 +844,8 @@ StringXNumber GeneralOptions_Number[] = {
     "Show tooltips in the user interface" },
   { F|O, "Trackball" , opt_general_trackball , 1. ,
     "Use trackball rotation mode" },
+  { F|O, "TrackballHyperbolicSheet" , opt_general_trackball_hyperbolic_sheet , 1. ,
+    "Use hyperbolic sheet away from trackball center for z-rotations" },
   { F,   "TrackballQuaternion0" , opt_general_quaternion0 , 0.0 , 
     "First trackball quaternion component (used if General.Trackball=1)" }, 
   { F,   "TrackballQuaternion1" , opt_general_quaternion1 , 0.0 , 
diff --git a/Common/Options.cpp b/Common/Options.cpp
index 979ae7fdd4994b0df09f07090a9d8e64c273fe50..a097d632cc2c66a58f49c793f1875b1012c9ac5e 100644
--- a/Common/Options.cpp
+++ b/Common/Options.cpp
@@ -3643,6 +3643,13 @@ double opt_general_trackball(OPT_ARGS_NUM)
   return CTX::instance()->useTrackball;
 }
 
+double opt_general_trackball_hyperbolic_sheet(OPT_ARGS_NUM)
+{
+  if(action & GMSH_SET)
+    CTX::instance()->trackballHyperbolicSheet = (int)val;
+  return CTX::instance()->trackballHyperbolicSheet;
+}
+
 double opt_general_rotation_center_cg(OPT_ARGS_NUM)
 {
   if(action & GMSH_SET)
diff --git a/Common/Options.h b/Common/Options.h
index ad1e78744eb55460119f7a38bd73de4118b52a57..f4a0813784dbd74181c832bdd9b6597a9aca39fb 100644
--- a/Common/Options.h
+++ b/Common/Options.h
@@ -345,6 +345,7 @@ double opt_general_arrow_head_radius(OPT_ARGS_NUM);
 double opt_general_arrow_stem_length(OPT_ARGS_NUM);
 double opt_general_arrow_stem_radius(OPT_ARGS_NUM);
 double opt_general_trackball(OPT_ARGS_NUM);
+double opt_general_trackball_hyperbolic_sheet(OPT_ARGS_NUM);
 double opt_general_rotation_center_cg(OPT_ARGS_NUM);
 double opt_general_zoom_factor(OPT_ARGS_NUM);
 double opt_general_expert_mode(OPT_ARGS_NUM);
diff --git a/Graphics/Trackball.cpp b/Graphics/Trackball.cpp
index a9caa2f0afd5d20d143207573a6f8fe1d1d217cc..fd3d628d70d5232672a898c8de13fa02a517ff24 100644
--- a/Graphics/Trackball.cpp
+++ b/Graphics/Trackball.cpp
@@ -51,7 +51,7 @@
  */
 /*
  * Modified for inclusion in Gmsh (rotmatrix as a vector +
- * float->double + camera + new trackballsize function)
+ * float->double + optional use of hyperbolic sheet for z-rotation)
  */
 #include <math.h>
 #include "Trackball.h"
@@ -233,14 +233,7 @@ tb_project_to_sphere(double r, double x, double y)
 
   d = sqrt(x*x + y*y);
 
-  if (CTX::instance()->camera) {
-    if (d < r ) {    
-      z = sqrt(r*r - d*d);
-    } else {           
-      z = 0.;
-    }
-  }
-  else{
+  if (CTX::instance()->trackballHyperbolicSheet) {
     if (d < r * 0.70710678118654752440) {    
       // Inside sphere 
       z = sqrt(r*r - d*d);
@@ -250,6 +243,13 @@ tb_project_to_sphere(double r, double x, double y)
       z = t*t / d;
     }
   }
+  else{
+    if (d < r ) {    
+      z = sqrt(r*r - d*d);
+    } else {           
+      z = 0.;
+    }
+  }
 
   return z;
 }
@@ -345,8 +345,3 @@ build_rotmatrix(double m[16], double q[4])
     m[14] = 0.0;
     m[15] = 1.0;
 }
-
-double trackballsize()
-{
-  return TRACKBALLSIZE;
-}
diff --git a/utils/api_demos/mainGlut.cpp b/utils/api_demos/mainGlut.cpp
index e7011fa84665acae19be8114c63a6ce1fefba654..e16a0dbfafd708e8377504d3841436f601846b4f 100644
--- a/utils/api_demos/mainGlut.cpp
+++ b/utils/api_demos/mainGlut.cpp
@@ -419,7 +419,8 @@ int main(int argc, char **argv)
   GmshSetOption("General", "Stereo", 0.);
   GmshSetOption("General", "Camera", 1.);
   GmshSetOption("General", "Orthographic", 0.);
- 
+  GmshSetOption("General", "TrackballHyperbolicSheet", 0.);
+
   if (strstr(argv[1],"-s") != NULL){
    camera.stereoEnable = true;
    cout<<"mode STEREO"<<endl;