I've had my own business for over six years. The ups are great...But the downs Really STINK...try going 4 months without a single dime come in...that'll make you think twice about your decision.
Can you make a living doing 3d modeling...is like saying can you make a living selling cookies, pulling teeth, (insert any ocupation here) in the end it has more to do with who you are and what you are willing to take in return for your services.
You will need to be a salesman, a draftsman, a 3d modeler, a business man, oh someone has to go buy printer cartridges and since it's just you...guess what you get to do. Oh and when a client calls and says can you change this and this and this and I need it by tomorrow morning...you get to tell your wife that even though its her birthday you will need to work tonight....anyway the list will go on and on....the succes or failure of your business depends on so many other factors other than whether or not you can produce quality 3d models. ask yourself this can I eat beans and rice for three monnths to save money when times are slow. Can I put aside money when I have extra to save up for the hard times. Can I work 24 hours a day for 3 days to meet a deadline and only bill for 20 hours even though it took me 60 hours. Will I have the diligence to get up every day and go to work and be productive....your at home and the tv the refirigerator, your bed, the back yard, the trash,....you will need the diligence to say to your self that this is work time and even though I'm home I need to focus on work right now. I can't tell you how many times I've gone up stairs for lunch and 3 hours later realize that I just lost 3 hours of work time during the day that I will need to make up at night...OH and when you are your own boss your work day goes from 8 hours a day to 24/7/365...Clients will call you and if you want to keep them happy you will take thier calls...
OK...I'll get off the soap box now...one last thing...If you have even the slighetest thought of starting your own business take my advice. DO IT...you will never regret doing it you may find that you do have what it takes. You will forever regret not doing it, but you will never regret doing it. Even if it is not as sucessful as you had hoped.