Question: I already tried this <http://hg.orfeo-toolbox.org/OTB-Qgis-plugins/> repository and couldn't get it...

This guy seems to have it: <http://www.elance.com/samples/orfeo-toolbox-qgis/24111664/>

Answer: 
This is how I installed it on Windows 8.1 running QGIS 2.18.16:

* Download zip file for Windows 64bit version from <https://www.orfeo-toolbox.org/download/>
* Unzipped it to a sensible location (i.e. not a temporary location)
* Start QGIS
* Go to menu option Processing > Options
* Expand Providers > Orfeo Toolbox
* For OTB application folder set the value to be the folder path to the bin folder, for example if you have unzipped the download to c:\scratch then the bin folder would be C:\Scratch\OTB-6.4.0-Win64\bin
* Set the OTB command line tools folder to the same bin folder
* Press OK
* If you get a Wrong value error message about a msys folder you then need to go to Providers > Grass Commands and clear the value in Msys folder, this is some sort of bug in QGIS.
* Restart QGIS

**IMPORTANT: Folder path must not have spaces, so c:\Program Files will not work!**

*This approach got it working but I have not fully tested all the functionality. The reason is that I was interested in a specific function that it had.*
I tried installing Orfeo Toolbox in QGIS on Mac and struggled a lot but eventually managed it. Here's how for any beginners confused by terminology:

<https://www.orfeo-toolbox.org/download/> (download MacOS)

Make sure the file does not end in .txt, if it does, remove this so it just ends in .run (On recent Mac OS, you need to Right click and "Get Info" for the file and delete the .txt in the "Name & Extension" box, not just rename it in Finder).

Go to terminal, navigate to your Downloads folder by entering

```
cd Downloads

```

Then run these commands:

```
chmod +x OTB-7.3.0-Darwin64.run

./OTB-7.3.0-Darwin64.run

```

(Making sure that the file path is correct). This will unpack the file.

Then go to QGIS > Preferences > Processing. Click on the Providers drop down menu, and select OTB.

Input the file path name of the otb application folder (will probably be something like `/lib/otb/applications`)

Then input the file path name of the main OTB folder.

Tick the activate box.

Press OK and you're done!