diff --git a/common.pri b/common.pri
index d8528852..71aa5102 100644
--- a/common.pri
+++ b/common.pri
@@ -9,6 +9,5 @@ include(bison.pri)
 include(cgal.pri)
 include(opencsg.pri)
 include(glew.pri)
-include(boost.pri)
 include(eigen.pri)
-
+include(boost.pri)
diff --git a/doc/testing.txt b/doc/testing.txt
index 8ab1cee4..bbd7c188 100644
--- a/doc/testing.txt
+++ b/doc/testing.txt
@@ -85,7 +85,7 @@ Some versions of Xvfb may fail, however.
 
 1. Trouble finding libraries on unix
 
- To help CMAKE find eigen2, OpenCSG, CGAL, Boost, and GLEW, you can use 
+ To help CMAKE find eigen, OpenCSG, CGAL, Boost, and GLEW, you can use 
  environment variables, just like for the main qmake & openscad.pro. Examples:
 
  OPENSCAD_LIBRARIES=$HOME cmake .
@@ -93,7 +93,7 @@ Some versions of Xvfb may fail, however.
  
  Valid variables are as follows:
 
- BOOSTDIR, CGALDIR, EIGEN2DIR, GLEWDIR, OPENCSGDIR, OPENSCAD_LIBRARIES
+ BOOSTDIR, CGALDIR, EIGENDIR, GLEWDIR, OPENCSGDIR, OPENSCAD_LIBRARIES
 
  When running, this might help find your locally built libraries (assuming
  you installed into $HOME)
diff --git a/eigen.pri b/eigen.pri
index 6f11a532..8037b6f9 100644
--- a/eigen.pri
+++ b/eigen.pri
@@ -2,18 +2,18 @@
 # which eigen to use:
 #
 # Priority
-# 3. EIGEN3DIR / EIGEN2DIR if set
+# 0. EIGENDIR if set (also EIGEN2DIR for backwards compatability)
 # 1. OPENSCAD_LIBRARIES eigen3
 # 2. OPENSCAD_LIBRARIES eigen2
-# 4. system's standard include paths for eigen3
-# 5. system's standard include paths for eigen2
+# 3. system's standard include paths for eigen3
+# 4. system's standard include paths for eigen2
 
 eigen {
 
 # read environment variables
 OPENSCAD_LIBRARIES_DIR = $$(OPENSCAD_LIBRARIES)
 EIGEN2_DIR = $$(EIGEN2DIR)
-EIGEN3_DIR = $$(EIGEN3DIR)
+EIGEN_DIR = $$(EIGENDIR)
 
 CONFIG(mingw-cross-env) {
   EIGEN_INCLUDEPATH = mingw-cross-env/include/eigen2
@@ -36,17 +36,14 @@ CONFIG(mingw-cross-env) {
 
 
 # Optionally specify location of Eigen using the 
-# EIGEN3DIR env. variable
-!isEmpty(EIGEN3_DIR) { 
-  EIGEN_INCLUDEPATH = $$EIGEN3_DIR
-  message("EIGEN3 location: $$EIGEN3_INCLUDEPATH")
-}
-
-# Optionally specify location of Eigen using the 
-# EIGEN2DIR env. variable
+# EIGENDIR env. variable (EIGEN2 for backwards compatability)
 !isEmpty(EIGEN2_DIR) { 
   EIGEN_INCLUDEPATH = $$EIGEN2_DIR
-  message("EIGEN2 location: $$EIGEN2_INCLUDEPATH")
+  message("User set EIGEN location: $$EIGEN2_INCLUDEPATH")
+}
+!isEmpty(EIGEN_DIR) { 
+  EIGEN_INCLUDEPATH = $$EIGEN_DIR
+  message("User set EIGEN location: $$EIGEN_INCLUDEPATH")
 }
 
 isEmpty(EIGEN_INCLUDEPATH) {
diff --git a/openscad.pro b/openscad.pro
index 6532c794..024b7881 100644
--- a/openscad.pro
+++ b/openscad.pro
@@ -3,8 +3,7 @@
 #   MPFRDIR
 #   BOOSTDIR
 #   CGALDIR
-#   EIGEN2DIR
-#   EIGEN3DIR
+#   EIGENDIR
 #   GLEWDIR
 #   OPENCSGDIR
 #   OPENSCAD_LIBRARIES
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 63e265fd..a268df19 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -179,18 +179,19 @@ if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
 endif()
 
 # Priority
-# 3. EIGEN3DIR / EIGEN2DIR if set
+# 3. EIGENDIR if set (EIGEN2DIR for backwards compatability)
 # 1. OPENSCAD_LIBRARIES eigen3
 # 2. OPENSCAD_LIBRARIES eigen2
 # 4. system's standard include paths for eigen3
 # 5. system's standard include paths for eigen2
 
-set(EIGEN3_DIR "$ENV{EIGEN3DIR}")
 set(EIGEN2_DIR "$ENV{EIGEN2DIR}")
+set(EIGEN_DIR "$ENV{EIGENDIR}")
 set(OPENSCAD_LIBDIR "$ENV{OPENSCAD_LIBRARIES}")
 
-if (EIGEN3_DIR)
-  find_path(EIGEN_INCLUDE_DIR Eigen/Core HINTS "${EIGEN3_DIR}/include/eigen3" "${EIGEN3_DIR}")
+if (EIGEN_DIR)
+  set(EIGEN_HINTS "${EIGEN_DIR}/include/eigen3" "${EIGEN_DIR}/include/eigen2" "${EIGEN_DIR}")
+  find_path(EIGEN_INCLUDE_DIR Eigen/Core HINTS "${EIGEN_HINTS}")
 endif()
 if (EIGEN2_DIR)
   find_path(EIGEN_INCLUDE_DIR Eigen/Core HINTS "${EIGEN2_DIR}/include/eigen2" "${EIGEN2_DIR}")