With the current version of houdini 16.5.295 win64 I have the problem that I cannot read npz files anymore. With standard numpy from standard python2.7 x64 I can read the files without any problem.
Has someone the same problem ?

Also with linux houdini it works without any problems ..

On OSX and Linux, Houdini uses the system Python where on Windows it uses a pre-installed Houdini version, so you will either have to install numpy into the site-packages for that version of Python, alter your PATH variable to point to the OS installed version. You will need to make sure that any packages are compiled with the right version of Python. Any easy solution that I have found for just a brute force thing is you can install the 2.7 version of Anaconda and use its site-packages..

Yes I know but even the windows version comes with numpy but this numpy version seems to have problems with npz since hou 16 ..

slowly things become clearer. under windows I cant easily install packages to the houdini python environment ( cause of same compiler as python host etc .. ). Thats why I was calling another standard python installation from the houdini env. In this special case to get access to matplotlib functionality. But I figured out that the problem is the environment which gets inherited from the houdini python. Is it possible to popen a cmd or python process with the vanilla environment ?