Update install instructions

README.md

@@ -5,7 +5,8 @@
 
 *MRtrix3* can be installed / run through multiple avenues:
 - [Direct download](https://www.mrtrix.org/download/) through mechanisms tailored for different OS platforms;
-- Compiled from the source code in this repository, for which [comprehensive instructions](https://mrtrix.readthedocs.io/en/latest/installation/build_from_source.html) are provided in the [online documentation](https://mrtrix.readthedocs.io/en/);
+- Compiled from the source code in this repository. A quick overview on how to do this is provided below, for a more comprehensive
+  overview of the process please see [here](https://github.com/MRtrix3/mrtrix3/wiki/Building-from-source).
 - Via containerisation technology using Docker or Singularity; see [online documentation page](https://mrtrix.readthedocs.org/en/latest/installation/using_containers.html) for details.
 
 ## Getting help
@@ -18,33 +19,32 @@ You can address all *MRtrix3*-related queries there, using your GitHub or Google
 ## Quick install
 
 1. Install dependencies by whichever means your system uses. 
-   These include: Python3, a C++ compiler with full C++11 support (`g++` 4.9 or later, `clang++`), 
+   These include: CMake (>= 3.16), Python3, a C++ compiler with full C++17 support, 
    Eigen (>=3.2.8), zlib, OpenGL (>=3.3), and Qt (>=5.5).
 
 2. Clone Git repository and compile:
 
         $ git clone https://github.com/MRtrix3/mrtrix3.git
         $ cd mrtrix3/
-        $ ./configure
-        $ ./build
+        $ cmake -B build -DCMAKE_INSTALL_PREFIX=/path/to/installation/
+        $ cmake --build build
+        $ cmake --install build
+
+    It's **highly** recommended, that you use [Ninja](https://ninja-build.org/) and a compiler caching tool like [ccache](https://ccache.dev/) or [sccache](https://github.com/mozilla/sccache) to speed up compilation time. You can install these tools using your package manager (e.g. `apt install ninja-build ccache` or `brew install ninja ccache`). Then, add `-GNinja` to the third step above or set the environment variable `CMAKE_GENERATOR` variable to `Ninja`.
 
 3. Set the `PATH`:
 
     * Bash shell:
 
-      run the `set_path` script provided:
-
-            $ ./set_path
-
-      or edit the startup `~/.bashrc` or `/etc/bash.bashrc` file manually by adding this line:
+      edit the startup `~/.bashrc` or `/etc/bash.bashrc` file manually by adding this line:
 
-            $ export PATH=/<edit as appropriate>/mrtrix3/bin:$PATH
+            $ export PATH=/path/to/installation/bin:$PATH
 
     * C shell:
 
       edit the startup `~/.cshrc` or `/etc/csh.cshrc` file manually by adding this line:
 
-            $ setenv PATH /<edit as appropriate>/mrtrix3/bin:$PATH
+            $ setenv PATH /path/to/installation/bin:$PATH
 
 4. Test installation:
 
@@ -61,22 +61,17 @@ You can address all *MRtrix3*-related queries there, using your GitHub or Google
 1. You can update your installation at any time by opening a terminal in the mrtrix3 folder, and typing:
 
         git pull
-        ./build
-
-2. If this doesn't work immediately, it may be that you need to re-run the configure script:
-
-        ./configure
-
-    and re-run step 1 again.
+        # Run CMake build instructions
 
 ## Building a specific release of MRtrix3
 
 You can build a particular release of MRtrix3 by checking out the corresponding _tag_, and using the same procedure as above to build it:
 
     git checkout 3.0_RC3
-    ./configure
-    ./build
-
+    # Run CMake build instructions
+
+NOTE: if you run into configuration errors, you may need to delete CMake's internal cache and reconfigure the project. You can do this by deleting the `CMakeCache.txt` file in your build directory.
+
 ## Contributing
 
 Thank you for your interest in contributing to *MRtrix3*! Please read on [here](CONTRIBUTING.md) to find out how to report issues, request features and make direct contributions.