What does that means and how to switch from 2D to 3D. I have a AMD Radeon7670M I tried installing and re installed the driver it recommended in additional drivers and i have checked synaptic package manager all the 2D and 3D related results are marked green.Now What to do i am very confused.
Okay, now I have faced this exact same problem myself and solved this a few days previously. My previous answer was in accordance with the standard procedure for troubles regarding logging in to Unity-3D
Apparently, the official drivers that are tested by Ubuntu are not being detected and are in effect worthless.
Here is the solution I found to the issue (quoting from another site) :
This worked for me just fine. Hope it works for you too.
Ah, this happened to me, and the solution is easy. First, log off. (Or go to the login screen.)
Now, as shown, click the Ubuntu Logo.
It will open this. Click 'Ubuntu' (Not Ubuntu 2D.) Then sign in as normal. Note: This will always be the default setting. To change it, use these steps again.
Sorry about the formatting. It's quite hard.
Oh, and the options on the 3rd image you might not have.(E.g. GNOME)Unless you installed them.
To log into the Unity-3D interface you will need to log out and log in again. This time click the icon next to the username and from the two options "Unity 2D" and "Unity" select the second one. Hopefully it will help you, if you have Unity-3D on your system.
To check if you have successfully logged into Unity-3D, run the following code in terminal:
It will return Unity or Unity 2D and you can verify your current session.
Run this code in terminal to check your support of the Unity 3D interface. You will get output that will identify capabilities of your graphics card; one of the items (the last in the list, I think) will tell you if you have "Unity 3D Support:" it'll either give you a "Yes" or a "No."
Unity 2D which is in Precise is a desktop designed to provide the Unity desktop shell on hardware platforms that cannot currently support Unity's OpenGL requirements.
On older machines the standard Unity desktop may not run very well. Unfortunately for those of us with older hardware it is not supported in 12.10 and I believe there is no intention to support it in future versions.
Its architecture is very close to Unity's as it only replaces the user interface elements but still shares all the same backend components. Specifically, Unity 2D replaces the panel, launcher and places components as defined in Unity's architecture overview. Moreover it does not enforce the use of Compiz as a window manager but instead uses a slightly tweaked version of Metacity.
Note: on some old hardware the normal (3D) Unity is not an option and Unity 2D is offered instead.
For more details see here Unity2D
If you want the Unity desktop log out then at the login screen click the circular icon next to you name and the password box. Select "Unity" as your desktop then login again.