UG means Under Graduate and PG is Post Graduate, these are the two levels of classifying the level of education. There are courses referred to as Degrees or Diploma based on these levels like Bachelor degree or Diploma courses fall in UG category and Masters, PG Diploma or PG Programs fall under the PG category.
In Animation, there are several types of courses available based on both the levels like Certificate courses, Bachelor programs and Diploma in Animation. Multimedia and so are there courses at PG level mostly PG diploma or Masters.
Depending on your qualification i.e. 12th, you are eligible for the Bachelor/ Diploma courses. Degree / Bachelors courses are a minimum of 3 years and are affiliated to a University where as the diploma are relatively shorter courses.
A quality of the students pursuing a course in animation depends less of the type of course, but mainly on the talent and skills possessed and ones inbuilt creativity.