This day any software development company begin to change their way of distributing an installer, there was the day when we just need to d0wnl0ad one installation file to use the software for like 5 or 10 months, but now every software is use word "update" to make us do the same thing over and over, i personally not a fan of those. One big issue is the internet connection, on my place internet isn't the strange thing anymore, everyone use it daily, but the perkara is the cost to have it. It's way to expensive for small developer or the student, considering they don't have enough fund to spend. And yes the speed and the stability of the connection is another thing to worry about. But what could i say that was the reality, like or dislike we need to follow it.
I'll stopping my talk, so this is the way you can get Unity 3D offline installer:
1. You need to install and d0wnl0ad torrent d0wnl0ader such as Utorrent.
2. Go to this URL: https://unity3d.com/get-unity/d0wnl0ad/archive
3. Scroll down until you find this section:
4. Choose/click on your platform (Win/Mac), then on the combo box choose on Torrent d0wnl0ad (Win+Mac).
5. After clicking it your torrent d0wnl0ader will automaticly open the torrent file.
6. You can either d0wnl0ad all the files or just d0wnl0ad your needed files like this:
7. Wait until all files d0wnl0aded.
Sumber http://farihinmuhamad.blogspot.com