diff --git a/3D-printing-101.md b/3D-printing-101.md
new file mode 100644
index 00000000..90bcbea7
--- /dev/null
+++ b/3D-printing-101.md
@@ -0,0 +1,7 @@
+# 3D printing
+
+* .f3D = Fusion360
+* .ipt = Inventor 2021 design file 
+* .STL = just 3D shape
+* .3MF = 3D print slicer file
+* .gcode = prusa file?