diff --git a/.github/workflows/ccpp_mac.yml b/.github/workflows/ccpp_mac.yml
index 9f64ec4fc..069f81226 100644
--- a/.github/workflows/ccpp_mac.yml
+++ b/.github/workflows/ccpp_mac.yml
@@ -8,7 +8,7 @@ on:
 jobs:
   build:
 
-    runs-on: macos-latest
+    runs-on: macos-10.15
     
     steps:
     - uses: actions/checkout@v2
diff --git a/.github/workflows/ccpp_mac_arm.yml b/.github/workflows/ccpp_mac_arm.yml
new file mode 100644
index 000000000..4c2ec279c
--- /dev/null
+++ b/.github/workflows/ccpp_mac_arm.yml
@@ -0,0 +1,28 @@
+name: C/C++ debug arm macos
+
+on:
+  push:
+    branches:
+      - Nigthly
+
+jobs:
+  build:
+
+    runs-on: macos-11
+    
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        ref: 'debug_macos'
+    - name: build deps & slicer
+      run: ./BuildMacOS.sh -ia
+    - name: Upload artifact
+      uses: actions/upload-artifact@v1.0.0
+      with:
+        name: nightly_macos_arm_debug.dmg
+        path: build/${{ github.event.repository.name }}.dmg
+    - name: Upload artifact
+      uses: actions/upload-artifact@v1.0.0
+      with:
+        name: nightly_arm_macos.tar
+        path: build/${{ github.event.repository.name }}.tar
diff --git a/.github/workflows/ccpp_mac_arm_debug.yml b/.github/workflows/ccpp_mac_arm_debug.yml
new file mode 100644
index 000000000..a1f7d7cd4
--- /dev/null
+++ b/.github/workflows/ccpp_mac_arm_debug.yml
@@ -0,0 +1,31 @@
+name: C/C++ debug arm macos
+
+on:
+  push:
+    branches:
+      - debug_macos
+
+jobs:
+  build:
+
+    runs-on: macos-11
+    
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        ref: 'debug_macos'
+    - name: build deps & slicer
+      run: ./BuildMacOS.sh -bia
+    - name: ls build
+      working-directory: ./build
+      run: ls
+    - name: Upload artifact
+      uses: actions/upload-artifact@v1.0.0
+      with:
+        name: nightly_macos_arm_debug.dmg
+        path: build/${{ github.event.repository.name }}.dmg
+    - name: Upload artifact
+      uses: actions/upload-artifact@v1.0.0
+      with:
+        name: nightly_arm_macos.tar
+        path: build/${{ github.event.repository.name }}.tar
diff --git a/.github/workflows/ccpp_mac_debug.yml b/.github/workflows/ccpp_mac_debug.yml
index e16b5cdf2..007dd5fde 100644
--- a/.github/workflows/ccpp_mac_debug.yml
+++ b/.github/workflows/ccpp_mac_debug.yml
@@ -10,104 +10,22 @@ jobs:
 
     runs-on: macos-latest
     
-    env:
-      EXEC_NAME: "${{ github.event.repository.name }}"
-      DBL_NAME: "${{ github.event.repository.name }}/${{ github.event.repository.name }}"
     steps:
     - uses: actions/checkout@v2
       with:
         ref: 'debug_macos'
-    - name: update submodule profiles
-      working-directory: ./resources/profiles
-      run: git submodule update --init
-    - id: lowercase_repo
-      uses: ASzc/change-string-case-action@v1
-      with:
-        string: ${{ github.event.repository.name }}
-    - name: set exec name
-      if: ${{ github.event.repository.name != 'Slic3r' }}
-      uses: allenevans/set-env@v2.0.0
-      with:
-        EXEC_NAME: "${{ steps.lowercase_repo.outputs.lowercase }}"
-    - name: change date in version
-      run: |
-        sed "s/+UNKNOWN/_$(date '+%F')/" version.inc > version.date.inc
-        mv version.date.inc version.inc
-    - name: mkdir in deps
-      run: mkdir deps/build
-    - name: cmake deps
-      working-directory: ./deps/build
-      run: cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_OSX_DEPLOYMENT_TARGET="10.13"
-    - name: make deps
-      working-directory: ./deps/build
-      run: make
-    - name: ls libs
-      working-directory: ./deps/build
-      run: ls ./destdir/usr/local/lib
-    - name: rename wxscintilla
-      working-directory: ./deps/build/destdir/usr/local/lib
-      run: cp libwxscintilla-3.1.a libwx_osx_cocoau_scintilla-3.1.a
-    - name: ls libs
-      working-directory: ./deps/build
-      run: ls ./destdir/usr/local/lib
-    - name: clean deps
-      working-directory: ./deps/build
-      run: rm -rf dep_*
-    - name: mkdir build
-      run: mkdir build
-    - name: cmake
+    - name: build deps & slicer
+      run: ./BuildMacOS.sh -bi
+    - name: tar the pack
       working-directory: ./build
-      run: cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_PREFIX_PATH="$PWD/../deps/build/destdir/usr/local" -DCMAKE_OSX_DEPLOYMENT_TARGET="10.13" -DSLIC3R_STATIC=1
-    - name: make ${{ github.event.repository.name }}
-      working-directory: ./build
-      run: make Slic3r
-    - name: make .mo
-      working-directory: ./build
-      run: make gettext_po_to_mo
-    - name: update Info.plist
-      working-directory: ./build/src
-      run: sed "s/+UNKNOWN/_$(date '+%F')/" Info.plist >Info.date.plist
-    - name: create directory and copy into it
-      working-directory: ./build
-      run: |
-        mkdir pack
-        mkdir pack/${{ github.event.repository.name }}
-        mkdir pack/${{ env.DBL_NAME }}.app
-        mkdir pack/${{ env.DBL_NAME }}.app/Contents
-        mkdir pack/${{ env.DBL_NAME }}.app/Contents/_CodeSignature
-        mkdir pack/${{ env.DBL_NAME }}.app/Contents/Frameworks
-        mkdir pack/${{ env.DBL_NAME }}.app/Contents/MacOS
-    - name: copy Resources
-      working-directory: ./build
-      run: |
-        cp -Rf ../resources pack/${{ env.DBL_NAME }}.app/Contents/Resources
-        cp pack/${{ env.DBL_NAME }}.app/Contents/Resources/icons/${{ github.event.repository.name }}.icns pack/${{ github.event.repository.name }}/${{ github.event.repository.name }}.app/Contents/resources/${{ github.event.repository.name }}.icns
-        cp src/Info.date.plist pack/${{ github.event.repository.name }}/${{ github.event.repository.name }}.app/Contents/Info.plist
-        echo -n -e 'APPL????\x0a' > PkgInfo
-        cp PkgInfo pack/${{ env.DBL_NAME }}.app/Contents/PkgInfo
-#        echo -n -e '\xff\xfeAPPL\x3f\x00\x3f\x00\x3f\x00\x3f\x00\x0a\x00' > PkgInfo
-    - name: copy bin and do not let it lower case
-      working-directory: ./build
-      run: |
-        cp -f src/${{ env.EXEC_NAME }} pack/${{ env.DBL_NAME }}.app/Contents/MacOS/${{ github.event.repository.name }}
-        chmod u+x pack/${{ env.DBL_NAME }}.app/Contents/MacOS/${{ github.event.repository.name }}
-        tar -cvf ${{ github.event.repository.name }}.tar pack/${{ github.event.repository.name }}
-    - name: create dmg
-      working-directory: ./build
-      run: |
-        hdiutil create -ov -fs HFS+ -volname "${{ github.event.repository.name }}" -srcfolder "pack/${{ github.event.repository.name }}" temp.dmg
-        hdiutil convert temp.dmg -format UDZO -o ${{ github.event.repository.name }}.dmg
-#    - name: signing Resources (creating CodeResources inside _CodeSignature)
-#      working-directory: .
-#      run: codesign -s <identity> Resources
-# maybe i should just try to do that on a separate pc and copy the file here, more secure as a signing process.
-    - name: Upload artifact
-      uses: actions/upload-artifact@v1.0.0
-      with:
-        name: nightly_macos.tar
-        path: build/${{ github.event.repository.name }}.tar
+      run: ls
     - name: Upload artifact
       uses: actions/upload-artifact@v1.0.0
       with:
         name: nightly_macos_debug.dmg
         path: build/${{ github.event.repository.name }}.dmg
+    - name: Upload artifact
+      uses: actions/upload-artifact@v1.0.0
+      with:
+        name: nightly_macos.tar
+        path: build/${{ github.event.repository.name }}.tar
diff --git a/BuildMacOS.sh b/BuildMacOS.sh
index 7c7da1b72..6442c0d61 100755
--- a/BuildMacOS.sh
+++ b/BuildMacOS.sh
@@ -3,6 +3,7 @@
 export ROOT=`pwd`
 export NCORES=`sysctl -n hw.ncpu`
 export CMAKE_INSTALLED=`which cmake`
+#export ARCH=$(uname -m)
 
 # Check if CMake is installed
 if [[ -z "$CMAKE_INSTALLED" ]]
@@ -11,18 +12,32 @@ then
     exit -1
 fi
 
-while getopts ":ih" opt; do
+while getopts ":iaxbh" opt; do
   case ${opt} in
     i )
         export BUILD_IMAGE="1"
         ;;
+    a )
+        export BUILD_ARCH="arm64"
+        ;;
+    x )
+        export BUILD_ARCH="x86_64"
+        ;;
+    b )
+        export BUILD_DEBUG="1"
+        ;;
     h ) echo "Usage: ./BuildMacOS.sh [-i]"
         echo "   -i: Generate DMG image (optional)"
+        echo "   -a: Build for arm64 (Apple Silicon)"
+        echo "   -x: Build for x86_64 (Intel)"
+        echo "   -b: Build with debug symbols"
         exit 0
         ;;
   esac
 done
 
+echo "Build architecture: ${BUILD_ARCH}"
+
 # mkdir build
 if [ ! -d "build" ]
 then
@@ -35,7 +50,7 @@ echo -n "[1/9] Updating submodules..."
     pushd resources/profiles
     git submodule update --init
     popd
-} > $ROOT/build/Build.log # Capture all command output
+} #> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 echo -n "[2/9] Changing date in version..."
@@ -43,7 +58,7 @@ echo -n "[2/9] Changing date in version..."
     # change date in version
     sed "s/+UNKNOWN/_$(date '+%F')/" version.inc > version.date.inc
     mv version.date.inc version.inc
-} &> $ROOT/build/Build.log # Capture all command output
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 # mkdir in deps
@@ -54,17 +69,31 @@ fi
 
 echo -n "[3/9] Configuring dependencies..."
 {
+    BUILD_ARGS=""
+    if [[ -n "$BUILD_ARCH" ]]
+    then
+        BUILD_ARGS="${BUILD_ARGS}  -DCMAKE_OSX_ARCHITECTURES:STRING=${BUILD_ARCH}"
+    fi
+    if [[ -n "$BUILD_DEBUG" ]]
+    then
+        BUILD_ARGS="${BUILD_ARGS} -DCMAKE_BUILD_TYPE=Debug"
+    fi
     # cmake deps
+    echo "Cmake command: cmake .. -DCMAKE_OSX_DEPLOYMENT_TARGET=\"10.13\" ${BUILD_ARCH} "
     pushd deps/build
-    cmake .. -DCMAKE_OSX_DEPLOYMENT_TARGET="10.13"
-} &> $ROOT/build/Build.log # Capture all command output
+    cmake .. -DCMAKE_OSX_DEPLOYMENT_TARGET="10.13" $BUILD_ARGS 
+    echo "ls deps/build:"
+    ls -al
+    echo "ls deps/build/dep_GLEW-prefix"
+    ls -al dep_GLEW-prefix
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 echo -n "[4/9] Building dependencies..."
 {
     # make deps
     make -j$NCORES
-} &> $ROOT/build/Build.log # Capture all command output
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 echo -n "[5/9] Renaming wxscintilla library..."
@@ -72,8 +101,10 @@ echo -n "[5/9] Renaming wxscintilla library..."
     # rename wxscintilla
     pushd destdir/usr/local/lib
     cp libwxscintilla-3.1.a libwx_osx_cocoau_scintilla-3.1.a
+    echo "ls deps/build/destdir/usr/local/lib"
+    ls -al
     popd
-} &> $ROOT/build/Build.log # Capture all command output
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 echo -n "[6/9] Cleaning dependencies..."
@@ -81,15 +112,25 @@ echo -n "[6/9] Cleaning dependencies..."
     # clean deps
     rm -rf dep_*
     popd
-} &> $ROOT/build/Build.log # Capture all command output
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 echo -n "[7/9] Configuring Slic3r..."
 {
+    BUILD_ARGS=""
+    if [[ -n "$BUILD_ARCH" ]]
+    then
+        BUILD_ARGS="${BUILD_ARGS} -DCMAKE_OSX_ARCHITECTURES=${BUILD_ARCH}"
+    fi
+    if [[ -n "$BUILD_DEBUG" ]]
+    then
+        BUILD_ARGS="-DCMAKE_BUILD_TYPE=Debug ${BUILD_ARGS}"
+    fi
     # cmake
     pushd build
-    cmake .. -DCMAKE_PREFIX_PATH="$PWD/../deps/build/destdir/usr/local" -DCMAKE_OSX_DEPLOYMENT_TARGET="10.13" -DSLIC3R_STATIC=1
-} &> $ROOT/build/Build.log # Capture all command output
+    echo "Cmake command: cmake .. -DCMAKE_PREFIX_PATH=\"$PWD/../deps/build/destdir/usr/local\" -DCMAKE_OSX_DEPLOYMENT_TARGET=\"10.13\" -DSLIC3R_STATIC=1 ${BUILD_ARGS}"
+    cmake .. -DCMAKE_PREFIX_PATH="$PWD/../deps/build/destdir/usr/local" -DCMAKE_OSX_DEPLOYMENT_TARGET="10.13" -DSLIC3R_STATIC=1 ${BUILD_ARGS}
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
 
 echo -n "[8/9] Building Slic3r..."
@@ -99,9 +140,14 @@ echo -n "[8/9] Building Slic3r..."
 
     # make .mo
     make gettext_po_to_mo
-} &> $ROOT/build/Build.log # Capture all command output
+} #&> $ROOT/build/Build.log # Capture all command output
 echo "done"
-
+echo "ls ROOT"
+ls $ROOT
+echo "ls ROOT/build"
+ls $ROOT/build
+echo "ls -al ROOT/build/src"
+ls -al $ROOT/build/src
 # Give proper permissions to script
 chmod 755 $ROOT/build/src/BuildMacOSImage.sh
 
@@ -111,3 +157,5 @@ then
 else
 	$ROOT/build/src/BuildMacOSImage.sh
 fi
+echo "ls -al ROOT/build"
+ls -al $ROOT/build
diff --git a/deps/CMakeLists.txt b/deps/CMakeLists.txt
index 4f7b08a48..603d3615f 100644
--- a/deps/CMakeLists.txt
+++ b/deps/CMakeLists.txt
@@ -39,6 +39,21 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
     option(DEP_WX_GTK3 "Build wxWidgets against GTK3" OFF)
 endif()
 
+set(IS_CROSS_COMPILE FALSE)
+
+if (APPLE)
+    set(CMAKE_FIND_FRAMEWORK LAST)
+    set(CMAKE_FIND_APPBUNDLE LAST)
+    list(FIND CMAKE_OSX_ARCHITECTURES ${CMAKE_SYSTEM_PROCESSOR} _arch_idx)
+    if (CMAKE_OSX_ARCHITECTURES AND _arch_idx LESS 0)
+        set(IS_CROSS_COMPILE TRUE)
+        string(REPLACE ";" "$<SEMICOLON>" CMAKE_OSX_ARCHS "${CMAKE_OSX_ARCHITECTURES}")
+        set(_cmake_osx_arch -DCMAKE_OSX_ARCHITECTURES:STRING=${CMAKE_OSX_ARCHS})
+        set(_cmake_args_osx_arch CMAKE_ARGS -DCMAKE_OSX_ARCHITECTURES:STRING=${CMAKE_OSX_ARCHS})
+        message("Detect Cross-compilation. Will build for target ${CMAKE_OSX_ARCHS}" )
+    endif ()
+endif ()
+
 # On developer machines, it can be enabled to speed up compilation and suppress warnings coming from IGL. 
 # FIXME:
 # Enabling this option is not safe. IGL will compile itself with its own version of Eigen while
@@ -61,7 +76,7 @@ function(prusaslicer_add_cmake_project projectname)
 
     set(_gen "")
     set(_build_j "-j${NPROC}")
-if (MSVC)
+    if (MSVC)
         set(_gen CMAKE_GENERATOR "${DEP_MSVC_GEN}" CMAKE_GENERATOR_PLATFORM "${DEP_PLATFORM}")
         set(_build_j "/m")
     endif ()
@@ -79,6 +94,7 @@ if (MSVC)
             -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
             -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
             -DBUILD_SHARED_LIBS:BOOL=OFF
+            ${_cmake_osx_arch}
             "${_configs_line}"
             ${DEP_CMAKE_OPTS}
             ${P_ARGS_CMAKE_ARGS}
@@ -181,6 +197,7 @@ if ("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
         DEPENDS dep_boost
         CONFIGURE_COMMAND ""
         BUILD_COMMAND ""
+        ${_cmake_args_osx_arch}
         INSTALL_COMMAND ${CMAKE_COMMAND} -E copy_directory
             "${CMAKE_CURRENT_BINARY_DIR}/dep_boost_polygon-prefix/src/dep_boost_polygon/include/boost/polygon"
             "${DESTDIR}/usr/local/include/boost/polygon"
diff --git a/deps/GMP/GMP.cmake b/deps/GMP/GMP.cmake
index a7fe19355..049e63816 100644
--- a/deps/GMP/GMP.cmake
+++ b/deps/GMP/GMP.cmake
@@ -22,10 +22,24 @@ else ()
 
     if (APPLE)
         if (${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
-            set(_gmp_build_tgt aarch64)
+            set(_gmp_build_arch aarch64)
+        else ()
+            set(_gmp_build_arch ${CMAKE_SYSTEM_PROCESSOR})
+        endif()
+        if (IS_CROSS_COMPILE)
+            if (${CMAKE_OSX_ARCHITECTURES} MATCHES "arm")
+                set(_gmp_host_arch aarch64)
+                set(_gmp_host_arch_flags "-arch arm64")
+            elseif (${CMAKE_OSX_ARCHITECTURES} MATCHES "x86_64")
+                set(_gmp_host_arch x86_64)
+                set(_gmp_host_arch_flags "-arch x86_64")
+            endif()
+            set(_gmp_ccflags "${_gmp_ccflags} ${_gmp_host_arch_flags} -mmacosx-version-min=${DEP_OSX_TARGET}")
+            set(_gmp_build_tgt --build=${_gmp_build_arch}-apple-darwin --host=${_gmp_host_arch}-apple-darwin)
+        else ()
+            set(_gmp_ccflags "${_gmp_ccflags} -mmacosx-version-min=${DEP_OSX_TARGET}")
+            set(_gmp_build_tgt "--build=${_gmp_build_arch}-apple-darwin")
         endif()
-        set(_gmp_ccflags "${_gmp_ccflags} -mmacosx-version-min=${DEP_OSX_TARGET}")
-        set(_gmp_build_tgt "--build=${_gmp_build_tgt}-apple-darwin")
     elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
         if (${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
             set(_gmp_ccflags "${_gmp_ccflags} -march=armv7-a") # Works on RPi-4
diff --git a/deps/MPFR/MPFR.cmake b/deps/MPFR/MPFR.cmake
index ddbb178d8..ea52dc402 100644
--- a/deps/MPFR/MPFR.cmake
+++ b/deps/MPFR/MPFR.cmake
@@ -24,6 +24,7 @@ else ()
         CONFIGURE_COMMAND env "CFLAGS=${_gmp_ccflags}" "CXXFLAGS=${_gmp_ccflags}" ./configure --prefix=${DESTDIR}/usr/local --enable-shared=no --enable-static=yes --with-gmp=${DESTDIR}/usr/local ${_gmp_build_tgt}
         BUILD_COMMAND make -j
         INSTALL_COMMAND make install
+        ${_cmake_args_osx_arch}
         DEPENDS dep_GMP
     )
 endif ()
diff --git a/deps/PNG/PNG.cmake b/deps/PNG/PNG.cmake
index e07afec6d..11357f9ef 100644
--- a/deps/PNG/PNG.cmake
+++ b/deps/PNG/PNG.cmake
@@ -5,18 +5,36 @@ else ()
     set(_disable_neon_extension "")
 endif ()
 
-prusaslicer_add_cmake_project(PNG 
-    GIT_REPOSITORY https://github.com/glennrp/libpng.git 
-    GIT_TAG v1.6.35
-    DEPENDS ${ZLIB_PKG}
-    CMAKE_ARGS
-        -DPNG_SHARED=OFF
-        -DPNG_STATIC=ON
-        -DPNG_PREFIX=prusaslicer_
-        -DPNG_TESTS=OFF
-        -DDISABLE_DEPENDENCY_TRACKING=OFF
-        ${_disable_neon_extension}
+if(APPLE AND IS_CROSS_COMPILE)
+# TODO: check if it doesn't create problem when compiling from arm to x86_64
+    prusaslicer_add_cmake_project(PNG 
+        GIT_REPOSITORY https://github.com/glennrp/libpng.git 
+        GIT_TAG v1.6.35
+        DEPENDS ${ZLIB_PKG}
+        PATCH_COMMAND       ${GIT_EXECUTABLE} checkout -f -- . && git clean -df &&
+                            ${GIT_EXECUTABLE} apply --whitespace=fix ${CMAKE_CURRENT_LIST_DIR}/macos-arm64.patch
+        CMAKE_ARGS
+            -DPNG_SHARED=OFF
+            -DPNG_STATIC=ON
+            -DPNG_PREFIX=prusaslicer_
+            -DPNG_TESTS=OFF
+            -DDISABLE_DEPENDENCY_TRACKING=OFF
+            ${_disable_neon_extension}
+    )
+else ()
+    prusaslicer_add_cmake_project(PNG 
+        GIT_REPOSITORY https://github.com/glennrp/libpng.git 
+        GIT_TAG v1.6.35
+        DEPENDS ${ZLIB_PKG}
+        CMAKE_ARGS
+            -DPNG_SHARED=OFF
+            -DPNG_STATIC=ON
+            -DPNG_PREFIX=prusaslicer_
+            -DPNG_TESTS=OFF
+            -DDISABLE_DEPENDENCY_TRACKING=OFF
+            ${_disable_neon_extension}
 )
+endif()
 
 if (MSVC)
     add_debug_dep(dep_PNG)
diff --git a/deps/PNG/macos-arm64.patch b/deps/PNG/macos-arm64.patch
new file mode 100644
index 000000000..468d35685
--- /dev/null
+++ b/deps/PNG/macos-arm64.patch
@@ -0,0 +1,65 @@
+Based on https://github.com/vespakoen/libpng to work around until
+https://github.com/glennrp/libpng/pull/354 is resolved.
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 4db9bb87d..9099d1edf 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -82,10 +82,22 @@ option(PNG_HARDWARE_OPTIMIZATIONS "Enable Hardware Optimizations" ON)
+ set(PNG_PREFIX "" CACHE STRING "Prefix to add to the API function names")
+ set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")
+ 
++# CMake currently sets CMAKE_SYSTEM_PROCESSOR to one of x86_64 or arm64 on macOS,
++# based upon the OS architecture, not the target architecture. As such, we need
++# to check CMAKE_OSX_ARCHITECTURES to identify which hardware-specific flags to
++# enable. Note that this will fail if you attempt to build a universal binary in
++# a single cmake invokation.
++if (APPLE AND CMAKE_OSX_ARCHITECTURES)
++  set(TARGET_ARCH ${CMAKE_OSX_ARCHITECTURES})
++else()
++  set(TARGET_ARCH ${CMAKE_SYSTEM_PROCESSOR})
++endif()
++
++
+ if(PNG_HARDWARE_OPTIMIZATIONS)
+ # set definitions and sources for arm
+-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
+-  CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
++if(TARGET_ARCH MATCHES "^arm" OR
++   TARGET_ARCH MATCHES "^aarch64")
+   set(PNG_ARM_NEON_POSSIBLE_VALUES check on off)
+   set(PNG_ARM_NEON "check" CACHE STRING "Enable ARM NEON optimizations:
+      check: (default) use internal checking code;
+@@ -114,8 +126,8 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
+ endif()
+ 
+ # set definitions and sources for powerpc
+-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
+-	CMAKE_SYSTEM_PROCESSOR MATCHES "^ppc64*" )
++if(TARGET_ARCH MATCHES "^powerpc*" OR
++       TARGET_ARCH MATCHES "^ppc64*" )
+   set(PNG_POWERPC_VSX_POSSIBLE_VALUES on off)
+   set(PNG_POWERPC_VSX "on" CACHE STRING "Enable POWERPC VSX optimizations:
+      off: disable the optimizations.")
+@@ -138,8 +150,8 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
+ endif()
+ 
+ # set definitions and sources for intel
+-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
+-	CMAKE_SYSTEM_PROCESSOR MATCHES "^x86_64*" )
++if(TARGET_ARCH MATCHES "^i?86" OR
++       TARGET_ARCH MATCHES "^x86_64*" )
+   set(PNG_INTEL_SSE_POSSIBLE_VALUES on off)
+   set(PNG_INTEL_SSE "on" CACHE STRING "Enable INTEL_SSE optimizations:
+      off: disable the optimizations")
+@@ -162,8 +174,8 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
+ endif()
+ 
+ # set definitions and sources for MIPS
+-if(CMAKE_SYSTEM_PROCESSOR MATCHES "mipsel*" OR
+-	CMAKE_SYSTEM_PROCESSOR MATCHES "mips64el*" )
++if(TARGET_ARCH MATCHES "mipsel*" OR
++        TARGET_ARCH MATCHES "mips64el*" )
+   set(PNG_MIPS_MSA_POSSIBLE_VALUES on off)
+   set(PNG_MIPS_MSA "on" CACHE STRING "Enable MIPS_MSA optimizations:
+      off: disable the optimizations")
diff --git a/deps/deps-macos.cmake b/deps/deps-macos.cmake
index c3afdf90f..ea170f608 100644
--- a/deps/deps-macos.cmake
+++ b/deps/deps-macos.cmake
@@ -15,6 +15,24 @@ set(DEP_CMAKE_OPTS
 
 include("deps-unix-common.cmake")
 
+if (IS_CROSS_COMPILE)
+    if (${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
+        set(_build_arch aarch64)
+    elseif (${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64")
+        set(_build_arch x86_64)
+    endif()
+
+    if (${CMAKE_OSX_ARCHITECTURES} MATCHES "arm")
+        set(_host_arch aarch64)
+        set(_arch_flags "-arch arm64")
+    elseif (${CMAKE_OSX_ARCHITECTURES} MATCHES "x86_64")
+        set(_host_arch x86_64)
+        set(_arch_flags "-arch x86_64")
+    endif()
+    set(_boost_linkflags "linkflags=${_arch_flags}")
+    set(_build_tgt --build=${_build_arch}-apple-darwin --host=${_host_arch}-apple-darwin)
+    set(_env_curl env "CFLAGS=${_arch_flags}")
+endif ()
 
 ExternalProject_Add(dep_boost
     EXCLUDE_FROM_ALL 1
@@ -33,10 +51,11 @@ ExternalProject_Add(dep_boost
         variant=release
         threading=multi
         boost.locale.icu=off
-        "cflags=-fPIC -mmacosx-version-min=${DEP_OSX_TARGET}"
-        "cxxflags=-fPIC -mmacosx-version-min=${DEP_OSX_TARGET}"
-        "mflags=-fPIC -mmacosx-version-min=${DEP_OSX_TARGET}"
-        "mmflags=-fPIC -mmacosx-version-min=${DEP_OSX_TARGET}"
+        "cflags=-fPIC ${_arch_flags} -mmacosx-version-min=${DEP_OSX_TARGET}"
+        "cxxflags=-fPIC ${_arch_flags} -mmacosx-version-min=${DEP_OSX_TARGET}"
+        "mflags=-fPIC ${_arch_flags} -mmacosx-version-min=${DEP_OSX_TARGET}"
+        "mmflags=-fPIC ${_arch_flags} -mmacosx-version-min=${DEP_OSX_TARGET}"
+        ${_boost_linkflags}
         install
     INSTALL_COMMAND ""   # b2 does that already
 )
@@ -46,7 +65,8 @@ ExternalProject_Add(dep_libcurl
     URL "https://curl.haxx.se/download/curl-7.58.0.tar.gz"
     URL_HASH SHA256=cc245bf9a1a42a45df491501d97d5593392a03f7b4f07b952793518d97666115
     BUILD_IN_SOURCE 1
-    CONFIGURE_COMMAND ./configure
+    CONFIGURE_COMMAND ${_env_curl} ./configure
+        ${_build_tgt}
         --enable-static
         --disable-shared
         "--with-ssl=${DESTDIR}/usr/local"
@@ -87,4 +107,4 @@ ExternalProject_Add(dep_libcurl
     INSTALL_COMMAND make install "DESTDIR=${DESTDIR}"
 )
 
-add_dependencies(dep_openvdb dep_boost)
\ No newline at end of file
+add_dependencies(dep_openvdb dep_boost)
diff --git a/deps/deps-unix-common.cmake b/deps/deps-unix-common.cmake
index 46c9f8864..e4c4a824e 100644
--- a/deps/deps-unix-common.cmake
+++ b/deps/deps-unix-common.cmake
@@ -27,6 +27,7 @@ ExternalProject_Add(dep_tbb
         -DTBB_BUILD_TESTS=OFF
         -DCMAKE_CXX_FLAGS=${TBB_MINGW_WORKAROUND}
         -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
+        ${_cmake_osx_arch}
         ${DEP_CMAKE_OPTS}
 )
 
@@ -34,7 +35,10 @@ ExternalProject_Add(dep_gtest
     EXCLUDE_FROM_ALL 1
     URL "https://github.com/google/googletest/archive/release-1.8.1.tar.gz"
     URL_HASH SHA256=9bf1fe5182a604b4135edc1a425ae356c9ad15e9b23f9f12a02e80184c3a249c
-    CMAKE_ARGS -DBUILD_GMOCK=OFF ${DEP_CMAKE_OPTS} -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
+    CMAKE_ARGS
+        -DBUILD_GMOCK=OFF ${DEP_CMAKE_OPTS}
+        -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
+        ${_cmake_osx_arch}
 )
 
 ExternalProject_Add(dep_cereal
@@ -44,6 +48,7 @@ ExternalProject_Add(dep_cereal
     CMAKE_ARGS
         -DJUST_INSTALL_CEREAL=on
         -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
+        ${_cmake_osx_arch}
         ${DEP_CMAKE_OPTS}
 )
 
@@ -58,6 +63,7 @@ ExternalProject_Add(dep_nlopt
         -DNLOPT_MATLAB=OFF
         -DNLOPT_GUILE=OFF
         -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
+        ${_cmake_osx_arch}
         ${DEP_CMAKE_OPTS}
 )
 
@@ -70,6 +76,7 @@ ExternalProject_Add(dep_qhull
     CMAKE_ARGS
         -DBUILD_SHARED_LIBS=OFF
         -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
+        ${_cmake_osx_arch}
         ${DEP_CMAKE_OPTS}
 )
 
@@ -88,14 +95,30 @@ ExternalProject_Add(dep_blosc
         -DBUILD_TESTS=OFF 
         -DBUILD_BENCHMARKS=OFF 
         -DPREFER_EXTERNAL_ZLIB=ON
+        ${_cmake_osx_arch}
     PATCH_COMMAND       ${GIT_EXECUTABLE} reset --hard && git clean -df && 
                         ${GIT_EXECUTABLE} apply --whitespace=fix ${CMAKE_CURRENT_SOURCE_DIR}/blosc-mods.patch
 )
 
+# Check if we're building for arm on x86_64 and just for OpenEXR, build fat
+# binaries.  We need this because it compiles some code to generate other
+# source and we need to be able to run the executables.  When we link the
+# library, the x86_64 part will be ignored.
+if (APPLE AND IS_CROSS_COMPILE)
+    if (${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64" AND ${CMAKE_OSX_ARCHITECTURES} MATCHES "arm")
+        set(_openexr_arch arm64^^x86_64)
+        set(_openxr_list_sep LIST_SEPARATOR ^^)
+        set(_cmake_openexr_arch -DCMAKE_OSX_ARCHITECTURES:STRING=${_openexr_arch})
+    else()
+        set(_openexr_arch ${CMAKE_OSX_ARCHITECTURES})
+        set(_cmake_openexr_arch -DCMAKE_OSX_ARCHITECTURES:STRING=${_openexr_arch})
+    endif()
+endif()
 ExternalProject_Add(dep_openexr
     EXCLUDE_FROM_ALL 1
     GIT_REPOSITORY https://github.com/openexr/openexr.git
     GIT_TAG eae0e337c9f5117e78114fd05f7a415819df413a #v2.4.0 
+    ${_openxr_list_sep}
     CMAKE_ARGS
         -DCMAKE_INSTALL_PREFIX=${DESTDIR}/usr/local
         -DBUILD_SHARED_LIBS=OFF
@@ -104,6 +127,7 @@ ExternalProject_Add(dep_openexr
         -DPYILMBASE_ENABLE:BOOL=OFF 
         -DOPENEXR_VIEWERS_ENABLE:BOOL=OFF
         -DOPENEXR_BUILD_UTILS:BOOL=OFF
+        ${_cmake_openexr_arch}
 )
 
 ExternalProject_Add(dep_openvdb
@@ -124,6 +148,7 @@ ExternalProject_Add(dep_openvdb
         -DTBB_STATIC=ON
         -DOPENVDB_BUILD_VDB_PRINT=ON
         -DDISABLE_DEPENDENCY_VERSION_CHECKS=ON
+        ${_cmake_osx_arch}
     PATCH_COMMAND PATCH_COMMAND     ${GIT_EXECUTABLE} checkout -f -- . && git clean -df && 
                                     ${GIT_EXECUTABLE} apply --whitespace=fix ${CMAKE_CURRENT_SOURCE_DIR}/openvdb-mods.patch
 )