Removed cmake and git dependencies. Why not.

install.sh

 #!/bin/bash
-module load cmake/3.16.4
 module load gcc/10
 
 mkdir dependencies
 cd dependencies
 
+# Install CMake.
+wget https://github.com/Kitware/CMake/releases/download/v3.19.4/cmake-3.19.4-Linux-x86_64.tar.gz
+ZIP=cmake-3.19.4-Linux-x86_64.tar.gz
+tar -xzvf $ZIP
+rm $ZIP
+mv ./cmake-3.19.4-Linux-x86_64 ./cmake-3.19.4
+
 # Install Ospray.
 wget https://github.com/ospray/ospray/releases/download/v1.8.5/ospray-1.8.5.x86_64.linux.tar.gz
 ZIP=ospray-1.8.5.x86_64.linux.tar.gz
@@ -13,19 +19,21 @@ rm $ZIP
 mv ./ospray-1.8.5.x86_64.linux ./ospray-1.8.5
 
 # Install VTK.
-git clone https://github.com/Kitware/VTK.git
-cd VTK
-git checkout v9.0.1
+wget https://www.vtk.org/files/release/9.0/VTK-9.0.1.tar.gz
+ZIP=VTK-9.0.1.tar.gz
+tar -xzvf $ZIP
+rm $ZIP
+cd VTK-9.0.1
 mkdir build
 cd build
 export ospray_DIR=../../ospray-1.8.5/lib/cmake/ospray-1.8.5
-cmake .. -DVTK_MODULE_ENABLE_VTK_RenderingRayTracing=YES
-cmake --build . --config Release --parallel 64
+../../cmake-3.19.4/bin/cmake .. -DVTK_MODULE_ENABLE_VTK_RenderingRayTracing=YES
+../../cmake-3.19.4/bin/cmake --build . --config Release --parallel 64
 
 # Install application.
-cd ../../offline_ray_tracer
+cd ../../../offline_ray_tracer
 mkdir build
 cd build
-export VTK_DIR=../../../dependencies/VTK/build
-cmake ..
-cmake --build . --clean-first --config Release --parallel 64
+export VTK_DIR=../../dependencies/VTK-9.0.1/build/lib64/cmake/vtk-9.0/
+../../dependencies/cmake-3.19.4/bin/cmake ..
+../../dependencies/cmake-3.19.4/bin/cmake --build . --clean-first --config Release --parallel 64