diff --git a/build.sh b/build.sh
index e1caa59..d7f1e17 100755
--- a/build.sh
+++ b/build.sh
@@ -2,13 +2,19 @@
 
 set -e
 
-builddefs=params.json
+# paramsets contains the location of the OpenSCAD parameter sets.
+# see https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Customizer#Saving_Parameters_value_in_JSON_file
+paramsets=params.json
 
+# run executes a program after printing the commandline to stdout.
 run () {
     echo "=== $*"
     "$@"
 }
 
+# render turns OpenSCAD echo into 3mf temperature changes.
+# 
+# It does this by kludging together a PrusaSlicer-specific Metadata file.
 render () {
     basename=$1; shift
     run openscad -o $basename "$@" temp-tower.scad 2>&1 | tee $basename.log
@@ -28,19 +34,20 @@ render () {
     rmdir Metadata
 }
 
+# paramsets lists all defined parameter sets, one per line.
 paramsets () {
-    cat $builddefs | jq -r '.parameterSets | keys[] | select(length > 0)'
+    cat $paramsets | jq -r '.parameterSets | keys[] | select(length > 0)'
 }
 
 case "$1" in
     -h|-help|--help)
         cat <<EOD
-Usage $0 [-paramsets] [PARAMSET ...]
+Usage: $0 [-paramsets] [PARAMSET ...]
 
 Generates .3mf files with temperature changes
 for each given parameter set.
 
-Parameter sets are specified in $builddefs.
+Parameter sets are specified in $paramsets.
 
 -paramsets   List all defined parameter sets, and exit.
 EOD
@@ -52,12 +59,12 @@ EOD
         ;;
     "")
         paramsets | while read paramset; do
-            render $paramset.3mf -P $paramset -p $builddefs
+            render $paramset.3mf -P $paramset -p $paramsets
         done
         ;;
     *)
         for paramset in "$@"; do
-            render $paramset.3mf -P $paramset -p $builddefs
+            render $paramset.3mf -P $paramset -p $paramsets
         done
         ;;
 esac