Can anyone advise if it is possible to import work done in a different DAW and bring it into Sonar X3 producer?
IE: Studio One to Sonar.
If yes....how can this be done. I have tried a few ways without any success.
 
Regards.
Thank you in advance for any replies.

It depends on what you want to import but my method is to export all of the tracks as wav files making sure they all start and end at the same point.  Then when you import the audio will all line up in the project and then you can mix.
 
This way you have to then recreate fx chains and things like that but normally I import in to Sonar to mix and want to start mixing with a clean slate. 

I normally do what Karhide suggests.  
 
You can also try exporting your project as an OMF file (it retains some of the project-related details) and then open that OMF in Sonar.   It should retain whatever details are relevant for both DAWs.

Slugbaby
I normally do what Karhide suggests.  
 
You can also try exporting your project as an OMF file (it retains some of the project-related details) and then open that OMF in Sonar.   It should retain whatever details are relevant for both DAWs.

I've tried the OMF method but found it does not give great results. 

Not 100% certain, but I think Studio One can import but not export OMF.
 
OMF is somewhat limited. Karhide's method is what I use. I export a raw WAV for each track but also one with any processing and such, so I can use either what another engineer thought was good or make my own changes.

If there is midi tracks involved then first Save the song from Studio one as a Midi file.
Then what I would do is have a copy of the audio folder from studio one on hand. 
Either that or export those from studio one as waves as mentioned above. This is harder to do if the audio is scattered all over the timeline. Best if there is a full track for each part starting at zero. 
Now OPEN the midi file in Sonar which will give you the tempo and what ever midi tracks were used. 
You can then insert the soft synth you will use. 
Now use the browser to drag and drop the audio files to newly created audio tracks in Sonar. 
Some nudging might be needed. 
 
 

+1 to the above advice.
 
If you look up "Export stems" it will give you a rundown of the options to get tracks out of Studio One (both with/without FX, etc.). The manual (page 170 of the Studio One 3 Reference Manual) is light on description, but there are more detailed YouTube posts. You can then "mass import" these into SONAR (they will be listed in the export folder with the prefix you chose at export) by selecting them all at the import dialog.

The easiest way to avoid having to manually place imported audio clips along the timeline or having to ensure they all start at the beginning of the project is to use the “broadcast wave” format.

Broadcast wave format is the same as .wav only it includes a time-stamp telling any DAW that handles the format (Sonar does) at what time point the beginning of the audio file should be placed. So a file exported from one DAW as a broadcast wave should automatically be imported into Sonar at the correct time point.

tlw
The easiest way to avoid having to manually place imported audio clips along the timeline or having to ensure they all start at the beginning of the project is to use the “broadcast wave” format.

The only caution there is that if you're exporting individual clips, you need to identify the track with which they belong so the right clips can be dragged into the right tracks. I generally select all the clips in a track and export so they become a single, complete track. 

Implicit in what everyone is saying is that there is no way to simply move a project from one DAW to another of a different type, and then fiddle with the controls and plugins from the original, which is what everyone would like to do. What you can do is to move audio, and MIDI data. So before you get too deep in the weeds, you need to decide what work you intend to do on the imported stuff. Obviously you will not be able to use plugins or virtual instruments if you do not have them on your machine, and even if you do you will not be able to undo changes these have already made to the audio you are importing. In many cases (maybe most) you are better off getting unprocessed (clean) or minimally processed data if your plan is to use your DAW to finish the mix. Data that has had work done on the dynamics (volume) is much more malleable than data that has had effects like reverb applied for example. Clearly if someone has made a mess of the effects or frequencies of the audio, you are not going to be able to fix that much by importing the over-processed mess into your DAW.