You're thinking of DS9 and VOY. TNG used models throughout its run. The only time the Enterprise-D was CGI was in some shots of GEN.
Funny, I could have sworn I read otherwise... Something about how the Enterprise D looked a little less "real" after abandoning the model for CGI. Maybe they mixed up the details with GEN.
I do know that DS9 and VOY had models... at what point did they transition to CGI exclusively?