From Academy Bylaws:
Article III, Section 1. Membership shall be by invitation of the Board of Governors. Invitations to active membership shall be limited to those persons active in the motion picture arts and sciences, or credited with screen achievements, or who have otherwise achieved distinction in the motion picture arts and sciences and who, in the opinion of the Board, are qualified for membership.
To be considered for invitation to Academy membership in the Visual Effects Branch an individual must:
(a) have been actively engaged for the past 8 years in the production of Visual Effects for theatrical motion pictures in a key creative position, including, but not limited to, Visual Effects Supervisor; Mechanical/Special Effects Supervisor/Coordinator; Computer Graphics Supervisor; Creature/Character Effects Supervisor; Visual Effects Director of Photography; Visual Effects Art Director; Model Effects Supervisor; Digital Effects Supervisor; Matte Painting Supervisor; Visual Effects Animation Supervisor; Special Technology Supervisor; Compositing Supervisor or Previs Supervisor.
(b) have been nominated for an Academy Award in the Visual Effects category in the most recent Awards year.
(c) have been in the Visual Effects field for 4 years and have achieved such special distinction where ¾ of the non-abstaining Visual Effects Branch Executive Committee members agree, membership should be extended.
Proposals must be accompanied by a letter from each sponsor which addresses, as specifically as possible, how the candidate meets one or another of the requirements above.