diff --git a/mrdna/segmentmodel.py b/mrdna/segmentmodel.py
index 4dee89b779c0252a198f5bd5bcee56c1d54f101e..e3d400988f368d455d7c9131cb3c62d8af3b7af7 100644
--- a/mrdna/segmentmodel.py
+++ b/mrdna/segmentmodel.py
@@ -2921,10 +2921,10 @@ proc calcforces {} {
             ## iterate through the model segments
             for s in self.segments:
                 if isinstance(s,DoubleStrandedSegment):
-                    print("## dsDNA! \n")
+                    tclFile.write("## dsDNA! \n")
                     draw_cylinder(s,10,"cyan")
                 elif isinstance(s,SingleStrandedSegment):
-                    print("## ssDNA! \n")
+                    tclFile.write("## ssDNA! \n")
                     draw_cylinder(s,3,"orange")
                 else:
                     raise Exception ("your model includes beads that are neither ssDNA nor dsDNA")