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