diff --git a/cmake/DownloadPrebuilts.cmake b/cmake/DownloadPrebuilts.cmake
index 9e8d3dfc..cd4711db 100644
--- a/cmake/DownloadPrebuilts.cmake
+++ b/cmake/DownloadPrebuilts.cmake
@@ -132,10 +132,11 @@ function(copy_dylibs LIBS)
         get_target_property(DYLIB_PATH ${LIB} LOCATION_${CMAKE_BUILD_TYPE})
         get_filename_component(DYLIB_FILENAME ${DYLIB_PATH} NAME)
         message(STATUS "Copying ${DYLIB_FILENAME}")
-        file(COPY ${DYLIB_PATH} DESTINATION ${CMAKE_BINARY_DIR}/${CMAKE_BUILD_TYPE})
+        file(COPY ${DYLIB_PATH} DESTINATION ${CMAKE_BINARY_DIR})
     endforeach ()
 endfunction ()
 
+
 #=======================================================================================================================
 if ("${SYSTEM_NAME_UPPER}" STREQUAL "LINUX")
 
@@ -157,13 +158,19 @@ if ("${SYSTEM_NAME_UPPER}" STREQUAL "LINUX")
     set(OpenCV_LIBS ${OpenCV_LINK_LIBS})
     set(OpenCV_LIBS_DEBUG ${OpenCV_LIBS})
     
-    build_external_lib("build_opencv_w_contrib_for_linux.sh" "${OpenCV_VERSION}" "${OpenCV_PREBUILT_DIR}")
+
+    if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+        download_lib("${OpenCV_PREBUILT_DIR}")
+    else ()
+        build_external_lib("build_opencv_w_contrib_for_linux.sh" "${OpenCV_VERSION}" "${OpenCV_PREBUILT_DIR}")
+    endif ()
+
 
     #################
     # g2o for Linux #
     #################
     
-    set(g2o_PREBUILT_DIR "linux_g2o")
+    set(g2o_PREBUILT_DIR "linux_g2o_20170730")
     set(g2o_DIR "${PREBUILT_PATH}/${g2o_PREBUILT_DIR}")
     set(g2o_INCLUDE_DIR "${g2o_DIR}/include")
 
@@ -175,8 +182,12 @@ if ("${SYSTEM_NAME_UPPER}" STREQUAL "LINUX")
                 INTERFACE_INCLUDE_DIRECTORIES "${g2o_INCLUDE_DIR}")
         set(g2o_LIBS ${g2o_LIBS} ${lib})
     endforeach (lib)
-    
-    build_external_lib("build_g2o_for_linux.sh" "" "${g2o_PREBUILT_DIR}")
+
+    if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+        download_lib("${g2o_PREBUILT_DIR}")
+    else ()
+        build_external_lib("build_g2o_for_linux.sh" "" "${g2o_PREBUILT_DIR}")
+    endif ()
 
     ####################
     # Assimp for Linux #
@@ -202,13 +213,18 @@ if ("${SYSTEM_NAME_UPPER}" STREQUAL "LINUX")
 
     set(assimp_LIBS assimp::assimp assimp::irrxml)
     
-    build_external_lib("build_assimp_for_linux.sh" "${assimp_VERSION}" "${assimp_PREBUILT_DIR}")
+    if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+        download_lib("${assimp_PREBUILT_DIR}")
+    else ()
+        build_external_lib("build_assimp_for_linux.sh" "${assimp_VERSION}" "${assimp_PREBUILT_DIR}")
+    endif ()
 
     #####################
     # OpenSSL for Linux #
     #####################
 
-    set(openssl_PREBUILT_DIR "linux_openssl")
+    set(openssl_VERSION "1.1.1h")
+    set(openssl_PREBUILT_DIR "linux_openssl_${openssl_VERSION}")
     set(openssl_DIR "${PREBUILT_PATH}/${openssl_PREBUILT_DIR}")
     set(openssl_INCLUDE_DIR ${openssl_DIR}/include)
 
@@ -221,7 +237,11 @@ if ("${SYSTEM_NAME_UPPER}" STREQUAL "LINUX")
         set(openssl_LIBS ${openssl_LIBS} ${lib})
     endforeach (lib)
     
-    build_external_lib("build_openssl_for_linux.sh" "OpenSSL_1_1_1h" "${openssl_PREBUILT_DIR}")
+    if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+        download_lib("${openssl_PREBUILT_DIR}")
+    else ()
+        build_external_lib("build_openssl_for_linux.sh" "" "${openssl_PREBUILT_DIR}")
+    endif ()
 
     ####################
     # Vulkan for Linux #
@@ -345,7 +365,7 @@ elseif ("${SYSTEM_NAME_UPPER}" STREQUAL "WINDOWS") #----------------------------
     ###################
 
     if (SL_BUILD_WAI)
-        set(g2o_PREBUILT_DIR "win64_g2o")
+        set(g2o_PREBUILT_DIR "win64_g2o_20170730")
         set(g2o_DIR "${PREBUILT_PATH}/${g2o_PREBUILT_DIR}")
         set(g2o_INCLUDE_DIR "${g2o_DIR}/include")
         set(g2o_LIB_DIR "${g2o_DIR}/lib")
@@ -557,14 +577,15 @@ elseif ("${SYSTEM_NAME_UPPER}" STREQUAL "DARWIN" AND
     # g2o for MacOS-x86_64 #
     ########################
 
-    set(g2o_PREBUILT_DIR "mac64_g2o")
+    set(g2o_PREBUILT_DIR "mac64_g2o_20170730")
     set(g2o_DIR "${PREBUILT_PATH}/${g2o_PREBUILT_DIR}")
     set(g2o_INCLUDE_DIR "${g2o_DIR}/include")
 
     foreach (lib ${g2o_LINK_LIBS})
         add_library(${lib} SHARED IMPORTED)
         set_target_properties(${lib} PROPERTIES
-                IMPORTED_LOCATION "${g2o_DIR}/Debug/lib${lib}.dylib"
+                IMPORTED_LOCATION "${g2o_DIR}/Release/lib${lib}.dylib"
+                IMPORTED_LOCATION_DEBUG "${g2o_DIR}/Debug/lib${lib}.dylib"
                 INTERFACE_INCLUDE_DIRECTORIES "${g2o_INCLUDE_DIR}")
         set(g2o_LIBS ${g2o_LIBS} ${lib})
     endforeach (lib)
@@ -761,7 +782,7 @@ elseif ("${SYSTEM_NAME_UPPER}" STREQUAL "DARWIN" AND
     # g2o for MacOS-arm64 #
     #######################
 
-    set(g2o_PREBUILT_DIR "macArm64_g2o")
+    set(g2o_PREBUILT_DIR "macArm64_g2o_20170730")
     set(g2o_DIR "${PREBUILT_PATH}/${g2o_PREBUILT_DIR}")
     set(g2o_INCLUDE_DIR "${g2o_DIR}/include")
     
diff --git a/externals/prebuild_scripts/build_assimp_for_linux.sh b/externals/prebuild_scripts/build_assimp_for_linux.sh
index 37f2c3de..fe51337d 100755
--- a/externals/prebuild_scripts/build_assimp_for_linux.sh
+++ b/externals/prebuild_scripts/build_assimp_for_linux.sh
@@ -87,8 +87,22 @@ cp LICENSE "$ZIPFOLDER"
 cp Readme.md "$ZIPFOLDER"
 
 if [ -d "../../prebuilt/$ZIPFILE" ]; then
-    rm -rf ../../prebuilt/$ZIPFILE
+    rm -rf "../../prebuilt/$ZIPFILE"
 fi
 
-mv "$ZIPFOLDER" "../../prebuilt/"
+if [ ! -d "../../prebuilt/" ]; then
+    mkdir "../../prebuilt/"
+fi
+
+echo "ls . : $(ls .)"
+echo "ls ../../ : $(ls ../../)"
+echo "ls ../../prebuilt : $(ls ../../prebuilt)"
+
+echo "cp -r $ZIPFOLDER ../../prebuilt/"
+echo "PWD IS $PWD"
+echo "../../prebuilt IS $PWD/../../prebuilt/"
+
+cp -r "$ZIPFOLDER" "../../prebuilt/"
+
+echo "prebuilt content is $(ls ../../prebuilt)"
 
diff --git a/externals/prebuild_scripts/build_g2o_for_linux.sh b/externals/prebuild_scripts/build_g2o_for_linux.sh
index 8a4d584f..b1a92b21 100755
--- a/externals/prebuild_scripts/build_g2o_for_linux.sh
+++ b/externals/prebuild_scripts/build_g2o_for_linux.sh
@@ -9,7 +9,7 @@ ZIPFILE="$ARCH"_g2o
 ZIPFOLDER="build/$ZIPFILE"
 BUILD_D=build/"$ARCH"_debug
 BUILD_R=build/"$ARCH"_release
-
+VERSION="20170730_git"
 clear
 echo "Building g2o using the sources in the thirdparty directory"
 if [ ! -d ../g2o ]
@@ -20,12 +20,15 @@ fi
 
 cd ../g2o
 
+git checkout $VERSION
+
 # Make build folder for debug version
 mkdir build
 rm -rf $BUILD_D
 mkdir "$BUILD_D"
 cd "$BUILD_D"
 
+
 # Run cmake to configure and generate the make files
 cmake \
     -DCMAKE_INSTALL_PREFIX=install \
diff --git a/externals/prebuild_scripts/build_g2o_for_mac64.sh b/externals/prebuild_scripts/build_g2o_for_mac64.sh
index b9a8e439..3fea1be4 100755
--- a/externals/prebuild_scripts/build_g2o_for_mac64.sh
+++ b/externals/prebuild_scripts/build_g2o_for_mac64.sh
@@ -1,25 +1,34 @@
 #!/bin/sh
-
+ 
 # ####################################################
 # Build script for g2o for mac64
 # ####################################################
-
+ 
 ARCH=mac64
-ZIPFILE="$ARCH"_g2o
-ZIPFOLDER=build/$ZIPFILE
+VERSION="20170730_git"
+ZIPFOLDER="$ARCH"_g2o_20170730
 BUILD_D=build/"$ARCH"_debug
 BUILD_R=build/"$ARCH"_release
-
+ 
 clear
+echo "Building g2o using the sources in the thirdparty directory"
+if [ ! -d ../g2o ]
+then
+    echo "g2o directory doesn't exists"
+    git clone https://github.com/RainerKuemmerle/g2o.git ../g2o
+fi
+ 
 echo "Building g2o using the sources in the thirdparty directory"
 cd ../g2o
-
+ 
+git checkout $VERSION
+ 
 # Make build folder for debug version
 mkdir build
 rm -rf $BUILD_D
 mkdir $BUILD_D
 cd $BUILD_D
-
+ 
 # Run cmake to configure and generate the make files
 cmake \
     -DCMAKE_OSX_ARCHITECTURES=x86_64 \
@@ -30,46 +39,51 @@ cmake \
     -DCMAKE_DEBUG_POSTFIX="" \
     -DEIGEN3_INCLUDE_DIR=../eigen \
     ../..
-
+ 
 # finally build it
 make -j8
-
+ 
 # copy all into install folder
 make install
 cd ../.. # back to g2o
-
+ 
 # Make build folder for release version
 rm -rf $BUILD_R
 mkdir $BUILD_R
 cd $BUILD_R
-
+ 
 # Run cmake to configure and generate the make files
 cmake \
+    -DCMAKE_OSX_ARCHITECTURES=x86_64 \
     -DCMAKE_INSTALL_PREFIX=install \
     -DG2O_BUILD_APPS=off \
     -DG2O_BUILD_EXAMPLES=off \
     -DCMAKE_BUILD_TYPE=Release \
     -DEIGEN3_INCLUDE_DIR=../eigen \
+    -DG2O_USE_OPENGL=off \
     ../..
-
+ 
 # finally build it
 make -j8
-
+ 
 # copy all into install folder
 make install
 cd ../.. # back to g2o
-
+ 
 # Create zip folder for debug and release version
-rm -rf $ZIPFOLDER
-mkdir $ZIPFOLDER
-cp -R $BUILD_R/install/include   $ZIPFOLDER/include
-cp -R $BUILD_R/install/lib       $ZIPFOLDER/Release
-cp -R $BUILD_D/install/lib       $ZIPFOLDER/Debug
-cp doc/license* $ZIPFOLDER
-cp README.md $ZIPFOLDER
-
-if [ -d "../prebuilt/$ZIPFILE" ]; then
-    rm -rf ../prebuilt/$ZIPFILE
-fi
-
-mv $ZIPFOLDER ../prebuilt
+rm -rf ../prebuilt/$ZIPFOLDER
+mkdir ../prebuilt/$ZIPFOLDER
+echo $BUILD_R
+echo $(pwd)
+echo ../prebuilt/$ZIPFOLDER
+cp -R $BUILD_R/install/include   ../prebuilt/$ZIPFOLDER/include
+cp -R $BUILD_R/install/lib       ../prebuilt/$ZIPFOLDER/Release
+cp -R $BUILD_D/install/lib       ../prebuilt/$ZIPFOLDER/Debug
+cp doc/license* ../prebuilt/$ZIPFOLDER
+cp README.md ../prebuilt/$ZIPFOLDER
+ 
+#if [ -d "../prebuilt/$ZIPFILE" ]; then
+#    rm -rf ../prebuilt/$ZIPFILE
+#fi
+ 
+#mv $ZIPFOLDER ../prebuilt
diff --git a/externals/prebuild_scripts/build_g2o_for_macArm64.sh b/externals/prebuild_scripts/build_g2o_for_macArm64.sh
index af473cff..b220a98e 100755
--- a/externals/prebuild_scripts/build_g2o_for_macArm64.sh
+++ b/externals/prebuild_scripts/build_g2o_for_macArm64.sh
@@ -1,25 +1,33 @@
 #!/bin/sh
-
+ 
 # ####################################################
 # Build script for g2o for macArm64
 # ####################################################
-
+ 
 ARCH="macArm64"
-ZIPFILE="$ARCH"_g2o
-ZIPFOLDER=build/$ZIPFILE
+VERSION="20170730_git"
+ZIPFOLDER="$ARCH"_g2o_20170730
 BUILD_D=build/"$ARCH"_debug
 BUILD_R=build/"$ARCH"_release
-
 clear
+echo "Building g2o using the sources in the thirdparty directory"
+if [ ! -d ../g2o ]
+then
+    echo "g2o directory doesn't exists"
+    git clone https://github.com/RainerKuemmerle/g2o.git ../g2o
+fi
+ 
 echo "Building g2o using the sources in the thirdparty directory"
 cd ../g2o
-
+ 
+git checkout $VERSION
+ 
 # Make build folder for debug version
 mkdir build
 rm -rf $BUILD_D
 mkdir $BUILD_D
 cd $BUILD_D
-
+ 
 # Run cmake to configure and generate the make files
 cmake \
     -DCMAKE_OSX_ARCHITECTURES=arm64 \
@@ -29,47 +37,51 @@ cmake \
     -DCMAKE_BUILD_TYPE=Debug \
     -DCMAKE_DEBUG_POSTFIX="" \
     -DEIGEN3_INCLUDE_DIR=../eigen \
+    -DG2O_USE_OPENGL=off \
     ../..
-
+ 
 # finally build it
 make -j8
-
+ 
 # copy all into install folder
 make install
 cd ../.. # back to g2o
-
+ 
 # Make build folder for release version
 rm -rf $BUILD_R
 mkdir $BUILD_R
 cd $BUILD_R
-
+ 
 # Run cmake to configure and generate the make files
 cmake \
+    -DCMAKE_OSX_ARCHITECTURES=arm64 \
     -DCMAKE_INSTALL_PREFIX=install \
     -DG2O_BUILD_APPS=off \
     -DG2O_BUILD_EXAMPLES=off \
     -DCMAKE_BUILD_TYPE=Release \
     -DEIGEN3_INCLUDE_DIR=../eigen \
     ../..
-
+ 
 # finally build it
 make -j8
-
+ 
 # copy all into install folder
 make install
 cd ../.. # back to g2o
-
+ 
 # Create zip folder for debug and release version
-rm -rf $ZIPFOLDER
-mkdir $ZIPFOLDER
-cp -R $BUILD_R/install/include   $ZIPFOLDER/include
-cp -R $BUILD_R/install/lib       $ZIPFOLDER/Release
-cp -R $BUILD_D/install/lib       $ZIPFOLDER/Debug
-cp doc/license* $ZIPFOLDER
-cp README.md $ZIPFOLDER
-
-if [ -d "../prebuilt/$ZIPFILE" ]; then
-    rm -rf ../prebuilt/$ZIPFILE
-fi
-
-mv $ZIPFOLDER ../prebuilt
+rm -rf ../prebuilt/$ZIPFOLDER
+mkdir ../prebuilt/$ZIPFOLDER
+echo "dst is ../prebuilt/$ZIPFOLDER/"
+cp -R $BUILD_R/install/include   ../prebuilt/$ZIPFOLDER/include
+cp -R $BUILD_R/install/lib       ../prebuilt/$ZIPFOLDER/Release
+cp -R $BUILD_D/install/lib       ../prebuilt/$ZIPFOLDER/Debug
+cp doc/license* ../prebuilt/$ZIPFOLDER
+cp README.md ../prebuilt/$ZIPFOLDER
+ 
+#if [ -d "../prebuilt/$ZIPFILE" ]; then
+#    rm -rf ../prebuilt/$ZIPFILE
+#fi
+ 
+#mv $ZIPFOLDER ../prebuilt
+ 
diff --git a/externals/prebuild_scripts/build_g2o_x64.bat b/externals/prebuild_scripts/build_g2o_x64.bat
index 04387a4e..78159681 100644
--- a/externals/prebuild_scripts/build_g2o_x64.bat
+++ b/externals/prebuild_scripts/build_g2o_x64.bat
@@ -19,9 +19,10 @@ set PATH=%PATH%;C:\Program Files (x86)\Git\bin
 
 :: build configuration
 set MAX_NUM_CPU_CORES=6
-set CMAKE_GENERATOR="Visual Studio 16 2019"
+::set CMAKE_GENERATOR="Visual Studio 16 2019"
 set CMAKE_ARCHITECTURE=x64
 set EIGEN_VERSION=3.3.3
+set VERSION=20170730_git
 
 :: g2o configuration flags
 set BUILD_APPS=OFF
@@ -34,12 +35,13 @@ set QGLVIEWER_DIR=%cd%\libQGLViewer\QGLViewer
 set QGLVIEWER_DEBUG_LIB=%cd%\libQGLViewer\QGLViewer\QGLViewerd2d.lib
 set QGLVIEWER_RELEASE_LIB=%cd%\libQGLViewer\QGLViewer\QGLViewerd2.lib
 set INSTALL_DIR=%cd%\g2o\INSTALL-vs
-set QT_DIR=A:\Qt\5.11.2\msvc2017_64\lib\cmake\Qt5
+::set QT_DIR=C:\ProgramData\chocolatey\lib\mingw\tools\install
+::set QT_DIR=A:\Qt\5.11.2\msvc2017_64\lib\cmake\Qt5
 
 echo QGLVIEWER_DIR %QGLVIEWER_DIR%
 echo QGLVIEWER_DEBUG_LIB %QGLVIEWER_DEBUG_LIB%
 echo QGLVIEWER_RELEASE_LIB %QGLVIEWER_RELEASE_LIB%
-echo QT_DIR %QT_DIR%
+::echo QT_DIR %QT_DIR%
 echo INSTALL_DIR %INSTALL_DIR%
 ::-----------------------------------------------------------------::
 :: get eigen
@@ -60,11 +62,14 @@ if not exist g2o (
 ) else (
     echo g2o already exists
 )
+
 cd g2o
+git checkout %VERSION%
 mkdir %INSTALL_DIR%
 mkdir BUILD-vs
 cd BUILD-vs
-cmake -G %CMAKE_GENERATOR% -A %CMAKE_ARCHITECTURE% -DEIGEN3_INCLUDE_DIR=..\eigen -DEigen3_DIR=..\eigen -DG2O_BUILD_APPS=%BUILD_APPS% -DG2O_BUILD_EXAMPLES=%BUILD_EXAMPLES% -DG2O_USE_CSPARSE=%USE_CSPARSE% -DG2O_USE_CHOLMOD=%USE_CHOLMOD% -DG2O_USE_OPENGL=%USE_OPENGL% -DQt5_DIR=%QT_DIR% -DQGLVIEWER_INCLUDE_DIR=%QGLVIEWER_DIR% -DQGLVIEWER_LIBRARY_DEBUG=%QGLVIEWER_DEBUG_LIB% -DQGLVIEWER_LIBRARY_RELEASE=%QGLVIEWER_RELEASE_LIB% -DCMAKE_INSTALL_PREFIX=%INSTALL_DIR% ..
+:: Removed -G %CMAKE_GENERATOR%  -DQt5_DIR=%QT_DIR%
+cmake -A %CMAKE_ARCHITECTURE% -DWINDOWS_EXPORT_ALL_SYMBOLS=ON -DEIGEN3_INCLUDE_DIR=..\eigen -DEigen3_DIR=..\eigen -DG2O_BUILD_APPS=%BUILD_APPS% -DG2O_BUILD_EXAMPLES=%BUILD_EXAMPLES% -DG2O_USE_CSPARSE=%USE_CSPARSE% -DG2O_USE_CHOLMOD=%USE_CHOLMOD% -DG2O_USE_OPENGL=%USE_OPENGL%  -DQGLVIEWER_INCLUDE_DIR=%QGLVIEWER_DIR% -DQGLVIEWER_LIBRARY_DEBUG=%QGLVIEWER_DEBUG_LIB% -DQGLVIEWER_LIBRARY_RELEASE=%QGLVIEWER_RELEASE_LIB% -DCMAKE_INSTALL_PREFIX=%INSTALL_DIR% ..
 msbuild INSTALL.vcxproj -maxcpucount:%MAX_NUM_CPU_CORES% /p:Configuration=Debug
 msbuild INSTALL.vcxproj -maxcpucount:%MAX_NUM_CPU_CORES% /p:Configuration=Release
 cd ..\..
diff --git a/externals/prebuild_scripts/build_opencv_w_contrib_for_linux.sh b/externals/prebuild_scripts/build_opencv_w_contrib_for_linux.sh
index 590359b5..85c4ec05 100755
--- a/externals/prebuild_scripts/build_opencv_w_contrib_for_linux.sh
+++ b/externals/prebuild_scripts/build_opencv_w_contrib_for_linux.sh
@@ -76,7 +76,7 @@ cmake \
 ../..
 
 # finally build it
-make -j8
+make -j16
 
 # copy all into install folder
 make install
@@ -85,8 +85,9 @@ cd ../.. # back to opencv
 # Make build folder for release version
 rm -rf $BUILD_R
 mkdir $BUILD_R
+echo "$BUILD_R and $BUILD_D"
 cd $BUILD_R
-
+#
 # Run cmake to configure and generate the make files
 cmake \
 -DCMAKE_CONFIGURATION_TYPES=Release \
@@ -110,7 +111,7 @@ cmake \
 ../..
 
 # finally build it
-make -j8
+make -j16
 
 # copy all into install folder
 make install
@@ -118,7 +119,9 @@ cd ../.. # back to opencv
 
 # Create zip folder for debug and release version
 rm -rf $ZIPFOLDER
-mkdir $ZIPFOLDER
+mkdir -p "$ZIPFOLDER"
+
+echo "$PWD/$BUILD_R/install/include $PWD/$ZIPFOLDER/include"
 cp -R $BUILD_R/install/include   $ZIPFOLDER/include
 cp -R $BUILD_R/install/lib       $ZIPFOLDER/Release
 cp -R $BUILD_D/install/lib       $ZIPFOLDER/Debug
@@ -131,8 +134,24 @@ fi
 cp LICENSE $ZIPFOLDER
 cp README.md $ZIPFOLDER
 
-if [ -d "../../prebuilt/$ZIPFILE" ]; then
-    rm -rf ../../prebuilt/$ZIPFILE
+if [ -d "../prebuilt/$ZIPFILE" ]; then
+    rm -rf "../prebuilt/$ZIPFILE"
 fi
 
-mv $ZIPFOLDER ../../prebuilt
+if [ ! -d "../../prebuilt/" ]; then
+    mkdir "../../prebuilt/"
+fi
+
+
+echo "ls . : $(ls .)"
+echo "ls ../../ : $(ls ../../)"
+echo "ls ../../prebuilt : $(ls ../../prebuilt)"
+
+
+echo "cp -r $ZIPFOLDER ../../prebuilt"
+echo "PWD IS $PWD"
+echo "../../prebuilt IS $PWD/../../prebuilt"
+cp -r "$ZIPFOLDER" "../../prebuilt"
+
+
+echo "prebuilt content is $(ls ../../prebuilt)"
diff --git a/externals/prebuild_scripts/build_opencv_w_contrib_for_win64.bat b/externals/prebuild_scripts/build_opencv_w_contrib_for_win64.bat
index f38c40a6..9ed1de06 100644
--- a/externals/prebuild_scripts/build_opencv_w_contrib_for_win64.bat
+++ b/externals/prebuild_scripts/build_opencv_w_contrib_for_win64.bat
@@ -17,7 +17,7 @@
 :: To enable downloading prebuilds copy 
 set PATH=%PATH%;C:\Program Files (x86)\Git\bin
 set MAX_NUM_CPU_CORES=6
-set CMAKE_GENERATOR="Visual Studio 16 2019"
+::set CMAKE_GENERATOR="Visual Studio 16 2019"
 set CMAKE_ARCHITECTURE=x64
 set OPENCV_VERSION=%1
 set SLPROJECT_ROOT=%2
@@ -58,7 +58,6 @@ git pull origin %OPENCV_VERSION%
 mkdir BUILD-%OPENCV_VERSION%-vs
 cd BUILD-%OPENCV_VERSION%-vs
 cmake ^
--G %CMAKE_GENERATOR% ^
 -A %CMAKE_ARCHITECTURE% ^
 -DWITH_CUDA=OFF ^
 -DOPENCV_EXTRA_MODULES_PATH=..\..\opencv_contrib\modules ^
diff --git a/externals/prebuild_scripts/build_openssl_for_linux.sh b/externals/prebuild_scripts/build_openssl_for_linux.sh
index 3f6d8f04..6e29d17e 100755
--- a/externals/prebuild_scripts/build_openssl_for_linux.sh
+++ b/externals/prebuild_scripts/build_openssl_for_linux.sh
@@ -5,14 +5,15 @@
 # ####################################################
 
 
+VERSION="1.1.1h"
 openssl_VERSION="OpenSSL_1_1_1h"
-if [ -n "$1" ]
-then
-    openssl_VERSION="$1"
-fi
+#if [ -n "$1" ]
+#then
+#    openssl_VERSION="$1"
+#fi
 
 ARCH=linux
-ZIPFILE=${ARCH}_openssl
+ZIPFILE=${ARCH}_openssl_${VERSION}
 
 clear
 echo "Building openssl Version: $openssl_VERSION"
diff --git a/modules/wai/source/orb_slam/Optimizer.cpp b/modules/wai/source/orb_slam/Optimizer.cpp
index bbe70486..91f06cc3 100644
--- a/modules/wai/source/orb_slam/Optimizer.cpp
+++ b/modules/wai/source/orb_slam/Optimizer.cpp
@@ -1554,15 +1554,17 @@ int Optimizer::OptimizeSim3(WAIKeyFrame*          pKF1,
     vSim3->setFixed(false);
 
     //replacement because of new  g2o (maybe this leads to errors...)
+#if defined(SL_OS_ANDROID) || defined(SL_OS_MACIOS)
     vSim3->_principle_point[0] = K1.at<float>(0, 2);
     vSim3->_principle_point[1] = K1.at<float>(1, 2);
     vSim3->_focal_length[0]    = K1.at<float>(0, 0);
     vSim3->_focal_length[1]    = K1.at<float>(1, 1);
-
-    //vSim3->_principle_point1[0] = K1.at<float>(0,2);
-    //vSim3->_principle_point1[1] = K1.at<float>(1,2);
-    //vSim3->_focal_length1[0] = K1.at<float>(0,0);
-    //vSim3->_focal_length1[1] = K1.at<float>(1,1);
+#else
+    vSim3->_principle_point1[0] = K1.at<float>(0,2);
+    vSim3->_principle_point1[1] = K1.at<float>(1,2);
+    vSim3->_focal_length1[0] = K1.at<float>(0,0);
+    vSim3->_focal_length1[1] = K1.at<float>(1,1);
+#endif
     //vSim3->_principle_point2[0] = K2.at<float>(0,2);
     //vSim3->_principle_point2[1] = K2.at<float>(1,2);
     //vSim3->_focal_length2[0] = K2.at<float>(0,0);