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 CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR I, Wolfram H. Blume, 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/ Wolfram H. Blume Wolfram H. Blume November 6, 1998 CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR I, Richard P. Magnuson, 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/ Richard P. Magnuson Richard P. Magnuson November 5, 1998 CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR I, John C. Savage, 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/ John C. Savage John C. Savage November 5, 1998 CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR I, Stephen W. Director, 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/ Stephen W. Director Stephen W. Director November 5, 1998