Index: trunk/psModules/src/objects/models/pmModel_PGAUSS.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_PGAUSS.c	(revision 27564)
+++ trunk/psModules/src/objects/models/pmModel_PGAUSS.c	(revision 27565)
@@ -287,4 +287,5 @@
 	// fprintf (stderr, "%f %f %f : %f %f\n", f, z, dz, dfdz, q);
 	z -= dz;
+	z = PS_MAX(z, 0.0);
     }
 
Index: trunk/psModules/src/objects/models/pmModel_PS1_V1.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_PS1_V1.c	(revision 27564)
+++ trunk/psModules/src/objects/models/pmModel_PS1_V1.c	(revision 27565)
@@ -313,4 +313,5 @@
 	// fprintf (stderr, "%f %f %f : %f %f\n", f, z, dz, dfdz, q);
 	z -= dz;
+	z = PS_MAX(z, 0.0);
     }
     psF64 radius = sigma * sqrt (2.0 * z);
Index: trunk/psModules/src/objects/models/pmModel_QGAUSS.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_QGAUSS.c	(revision 27564)
+++ trunk/psModules/src/objects/models/pmModel_QGAUSS.c	(revision 27565)
@@ -314,4 +314,5 @@
 	// fprintf (stderr, "%f %f %f : %f %f\n", f, z, dz, dfdz, q);
 	z -= dz;
+	z = PS_MAX(z, 0.0);
     }
     psF64 radius = sigma * sqrt (2.0 * z);
Index: trunk/psModules/src/objects/models/pmModel_RGAUSS.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_RGAUSS.c	(revision 27564)
+++ trunk/psModules/src/objects/models/pmModel_RGAUSS.c	(revision 27565)
@@ -307,4 +307,5 @@
 	// fprintf (stderr, "%f %f %f : %f %f\n", f, z, dz, dfdz, q);
 	z -= dz;
+	z = PS_MAX(z, 0.0);
     }