You are perfectly right, improvisation keeps you awake while making music. Plus, you're creating your very personal style, which I find very essential. In a conventional string orchestra they will probably not like it, because if you sound too much individually, it will likely irritate them. Well, I don't care and will never join an orchestra. Although, if you have a string section with violinists who all sound very personal, the result will be extremely expressive and simply wonderful.

BillyG said
I see "improvisation" on perhaps three different levels - and I'm sure there are more "specific" types - such as freestyle / jazz etc etc (neither of which I use - YET !)

(1) If I'm just practicing scales / arpeggios and generally "noodling around" - I'll break the boredom (and intentionally mix-up the practice) by inventing little musical phrases on-the-go.  Part of THAT improv is to also bring in bowing and rhythm practice. (Maybe not the most rigorous of ways to do it, but it works well for me).  And sometimes I'll end up with perhaps half of a little tune - of course - it won't be being recorded, and I'll never remember it !  The "danger" in doing this - for me - is that it can be too easy to suddenly find myself playing  a motif from some well known piece of music I have in my head - and suddenly I'm launching into Smoke on the Water or Country Roads or.... you name it....  but - I'm pretty strict with myself if/when that accidentally happens.

(2) Improv to an actual piece ( like a "backing" improv to as @damfino says - TW ).  For that sort of thing I would pick out the specific key changes and just "fill-in" a little bit of background/harmony.  And a bit like (1) above - the next time I would do that - it just wouldn't be the same - and that's fine.

(3) Improv to a "generic backing track" - here there IS no actual tune or melody to follow (like @Barry's current project) - in this case the backing track is just a repeated chord sequence Em, C, D, D   I like to approach these "play-alongs" in two different ways -

(3a) if it's a one-time-thing (i.e. never heard it before, and just leaping-in to "do something with it") - this - for me - would be a bit like (2) above where I would try to fit in to the tempo and follow the chord changes and "randomly" harmonise through each bar maybe with the chord tonic, 4th, 5th minor 3rd and so on - anything - so long as the note I play is not discordant.

(3b) If it is a "planned thing" - like Barry's recent project - I'll do a bit more - and listen to the backing track quite a few times through to get a feel in advance for chord sequences (although in this one, we are told in advance), timing and rhythm.  I'll specifically think about the notes belonging to each chord triad, and actively try to bring out an actual melody-line to what is originally just a "backing track".   

So - it's a bit questionable (to me) if (3b) above is true improvisation or not - it's almost kind of half-way between improv and composition of a tune/melody.   In my submission that's the path I took - and - I listened a few times to the backing track, and I "noodled around" with it for - oh - no more than 5 times - and each attempt was different from the others.  Finally - I recorded attempt 6 - and it contained "some ideas I had gathered" from the previous attempts - and - well - yes - I still see that as a form of improv - what I did was effectively "getting close to a regular melody" - but equally - it's never been written down, and if I do another take - I'm now in a "hard place" - do I "develop what I have got in my head" to a fully-finished-polished new piece - or do I just "vamp and noodle along to" the backing track and effectively "start again" - with the evolution of a completely different melody line.

Interesting....

Although started on the ViolaMan FB page, it's open to ANY interpretation - viola, violin, harp, voice, accordion, kazoo ( LOL).  Anyway - since my submission was on the violin I'll drop the link here -  - it IS improvisation, and it's FAR from perfect but you'll maybe get an idea of "where I was going with it".

Oh  -and this is the backing track found by Barry - feature=youtu.be

I hope it (and my ramblings above) provide inspiration - and demonstrate that improv is not all that difficult - and can be as simple as picking out individual notes to the point of almost inventing a melody....   free your spirit and embrace the music !  

Your style is not far from my style and the chords you're riding on are the kind I find in baroque music too. I love what you're doing there and know for sure, we could do something together if there wasn't that old Atlantic in the way.

I'm now playing more and more leading themes, but I started with just improvisation, so nothing would be between me and my violin and distract me from getting things technically on the point and the expression directly from my heart. I felt like notes would have distracted me as beginner.