diff --git a/CMakeLists.txt b/CMakeLists.txt
index d580306a..64eb23c4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -558,41 +558,33 @@ endif()
 
 ################################################################
 #
-# Locate CUDD bdd packagte
-# -DCUDD=0 to not use CUDD.
-# Look for library in CUDD/lib,     CUDD/cudd/lib
-# Look for header  in CUDD/include, CUDD/cudd/include
+# Locate CUDD bdd package.
 #
-if("${CUDD}" STREQUAL "" OR "${CUDD}" STREQUAL "0")
+find_library(CUDD_LIB
+  NAMES cudd
+  PATHS ENV CUDD
+  )
+if (CUDD_LIB)
+  message(STATUS "CUDD library: ${CUDD_LIB}")
+  get_filename_component(CUDD_LIB_DIR "${CUDD_LIB}" PATH)
+  get_filename_component(CUDD_LIB_PARENT1 "${CUDD_LIB_DIR}" PATH)
+  get_filename_component(CUDD_LIB_PARENT2 "${CUDD_LIB_PARENT1}" PATH)
+  find_file(CUDD_HEADER cudd.h
+    PATHS ${CUDD_LIB_PARENT1}/include ${CUDD_LIB_PARENT1}/include/cudd)
+  if (CUDD_HEADER)
+    get_filename_component(CUDD_INCLUDE "${CUDD_HEADER}" PATH)
+    message(STATUS "CUDD header: ${CUDD_HEADER}")
+    # CUDD referenced by StaConfig.hh.cmake
+    set(CUDD 1)
+  else()
+    message(STATUS "CUDD header: not found")
+  endif()
+else()
   set(CUDD_INCLUDE "")
   set(CUDD_LIB "")
   set(CUDD_FOUND FALSE)
   set(CUDD 0)
   message(STATUS "CUDD library: not found")
-else()
-  find_library(CUDD_LIB NAMES cudd PATHS ${CUDD}/lib ${CUDD}/lib/cudd)
-  if (CUDD_LIB)
-    message(STATUS "CUDD library: ${CUDD_LIB}")
-    get_filename_component(CUDD_LIB_DIR "${CUDD_LIB}" PATH)
-    get_filename_component(CUDD_LIB_PARENT1 "${CUDD_LIB_DIR}" PATH)
-    get_filename_component(CUDD_LIB_PARENT2 "${CUDD_LIB_PARENT1}" PATH)
-    find_file(CUDD_HEADER cudd.h
-      PATHS ${CUDD}/include ${CUDD_LIB_PARENT2}/include/cudd)
-    if (CUDD_HEADER)
-      get_filename_component(CUDD_INCLUDE "${CUDD_HEADER}" PATH)
-      message(STATUS "CUDD header: ${CUDD_HEADER}")
-      # CUDD referenced by StaConfig.hh.cmake
-      set(CUDD 1)
-    else()
-      message(STATUS "CUDD header: not found")
-    endif()
-  else()
-    set(CUDD_INCLUDE "")
-    set(CUDD_LIB "")
-    set(CUDD_FOUND FALSE)
-    set(CUDD 0)
-    message(STATUS "CUDD library: not found")
-  endif()
 endif()
 
 if("${SSTA}" STREQUAL "")
diff --git a/README.md b/README.md
index 1d9933c5..99e5ff68 100644
--- a/README.md
+++ b/README.md
@@ -80,11 +80,17 @@ libz     1.1.4   1.2.5     1.2.8
 cudd             2.4.1     3.0.0
 ```
 
-CUDD is a binary decision diageram (BDD) package that is used to improve conditional timing arc handling. OpenSTA does not require it to be installed. It is available [here](https://www.davidkebo.com/source/cudd_versions/cudd-3.0.0.tar.gz) or [here](https://sourceforge.net/projects/cudd-mirror/).
+CUDD is a binary decision diageram (BDD) package that is used to
+improve conditional timing arc handling. OpenSTA does not require it
+to be installed. It is available
+[here](https://www.davidkebo.com/source/cudd_versions/cudd-3.0.0.tar.gz)
+or [here](https://sourceforge.net/projects/cudd-mirror/).
 
 Note that the file hierarchy of the CUDD installation changed with version 3.0.
 Some changes to CMakeLists.txt are required to support older versions.
 
+The cmake file searchs in the normal places for the CUDD library.
+
 When building CUDD you may use the `--prefix ` option to `configure` to
 install in a location other than the default (`/usr/local/lib`).
 ```
@@ -93,21 +99,8 @@ mkdir $HOME/cudd
 ./configure --prefix $HOME/cudd
 make
 make install
-```
-To not use CUDD specify `CUDD=0`.
-Cmake looks for the CUDD library in `CUDD/lib, CUDD/cudd/lib`
-and for the header in `CUDD/include, CUDD/cudd/include`.
-```
-# equivalent to -DCUDD=0
-cmake ..                     
-or
-cmake .. -DCUDD=0
-or
-# look in ~/cudd/lib, ~/cudd/include
-cmake .. -DCUDD=$HOME/cudd
-or
-# look in /usr/local/lib/cudd, /usr/local/include/cudd
-cmake .. -DCUDD=/usr/local
+# export location of cudd for make to find it
+export CUDD=$HOME/cudd/lib
 ```
 
 The Zlib library is an optional.  If CMake finds libz, OpenSTA can