EXHIBIT 99.3 CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR I, Michael F. Bosworth, hereby consent to the use in the Registration Statement on Form S-4 of Summit Design, Inc. (the "Company") to which this consent is filed as an exhibit and the Joint Proxy Statement/Prospectus included therein, of my name as a person about to become a director of the Company. /s/ Michael F. Bosworth Michael F. Bosworth September 30, 1998