-# 3D printing utility files and build system
+This directory contains source code a number of objects of various
+kinds, and a simple build system.
-This is a set of files I use for making 3D objects.
+In general for a simple file FOO.scad you can say `make FOO.stl'.
-It mostly consists of my own work, but occasionally I include other
-people's work if that other work has a suitable licence.
-# Licence
+More complicated files contain source code for multiple related parts.
+The actual objects which might be printed or previewed are indicated
+in the source code with `///toplevel'. For a complicated file
+BAR.scad you can generate simple template openscad files, one for each
+such object, with `make BAR.auto.scads'. And you can make all the
+corresponding .stl files with `make BAR.auto.stls'.
+
+
+Many objects have `slop' in them, which represents an amount by which
+holes or gaps are bigger, in order to make things fit well. You will
+need to examine the openscad source or play around with previews to
+see which slop does what.
+
+
+Unless otherwise noted every object and file here is:
+
+ Copyright Ian Jackson
+ Licenced under the GNU General Public Licence, version 3, or
+ (at your option) any later version. There is NO WARRANTY.
-Everything is GPLv3+ (or compatible).