diff --git a/doc/erko_howto_tools.txt b/doc/erko_howto_tools.txt
index a810dee399b16b315e7995c5d4fa0816463bb5aa..c4b3b44bde90fa337d979c2b02240a95edd3c2b2 100755
--- a/doc/erko_howto_tools.txt
+++ b/doc/erko_howto_tools.txt
@@ -1639,6 +1639,16 @@ Reading package lists... Done
 > sudo apt-get install openscad
 Gelukt!
 
+To run swivel.scad simulation in OpenSCAD:
+
+> git clone https://github.com/erkooi/openscad
+> git clone https://github.com/erkooi/swivel
+
+Add in ~/bashrc :
+export OPENSCADPATH=/dop466_0/kooistra/github/openscad/math:/dop466_0/kooistra/github/openscad/shapes
+
+Run OpenSCAD from terminal:
+> openscad &
 
 *******************************************************************************
 * Drawio