build_vtk7.sh

#!/bin/bash

set -x
set -e

git clone https://github.com/Kitware/VTK.git

cd VTK
mkdir build
cd build

# we want to install it in our virtual environment
virtualenv_root=`python -c 'import sys; print(sys.prefix)'`

# we want to compile against our Python 3 installed with brew
brew_root="/usr/local/Cellar/python3/3.5.0/Frameworks/Python.framework/Versions/3.5"

cmake -D  BUILD_TESTING:BOOL=OFF \
      -D CMAKE_BUILD_TYPE:STRING=Release \
      -D CMAKE_INSTALL_PREFIX:PATH=${virtualenv_root} \
      -D VTK_WRAP_PYTHON:BOOL=ON \
      -D VTK_PYTHON_VERSION:STRING=3 \
      -D PYTHON_INCLUDE_DIR:PATH=${brew_root}/include/python3.5m/ \
      -D PYTHON_LIBRARY:FILEPATH=${brew_root}/lib/libpython3.5.dylib \
      -D VTK_INSTALL_PYTHON_MODULE_DIR:PATH=${virtualenv_root}/lib/python3.5/site-packages/ \
      ..

make -j4

make install

# add a line to your bash_profile:
# export DYLD_FALLBACK_LIBRARY_PATH=`python -c 'import sys; print(sys.prefix)'`/lib

Two small improvements: $virtualenv_root already exists as $VIRTUAL_ENV, and $brew_root should be determined by the output from python3.5-config --prefix.