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                             JOINT ESCROW INSTRUCTIONS

Perkins Coie (Hong Kong) Limited
23rd Floor
Asia Pacific Finance Tower
Citibank Plaza, 3 Garden Road
Hong Kong

Dear Sirs:

     As Escrow Agent for Summit Design Asia, Ltd., a Hong Kong corporation 
(the "Company"), and the undersigned holders of shares (the "Shares") 
representing all of the capital stock of the Company (each, a "Holder," and 
collectively, "Holders"), you are hereby authorized and directed to hold the 
Shares pursuant to the terms of that certain Shareholders Agreement 
("Agreement"), to which a copy of these Joint Escrow Instructions is attached 
as Exhibit D in accordance with the following instructions:

     1.   In the event Summit Design, Inc. ("Summit") determines to exercise 
its right, under Section 6.2.2(b) of the Agreement, to exchange its shares of 
Asia Design Corporation, Ltd., a Korean corporation ("ADC"), for all of the 
outstanding Shares not owned by Summit (the "Exchange Right"), Summit will 
give to you a written notice stating that it elects to exercise the Exchange 
Right, together with one or more certificates (or other evidence reasonably 
satisfactory to establish its transfer of the interest evidenced by such 
certificates) evidencing Summit's and the Company's ownership of shares of 
ADC. The Holders and the Company hereby irrevocably authorize and direct you 
to close the transaction contemplated by such notice in accordance with the 
terms of the notice.

     2.   At the closing you are directed (a) to date any stock assignments 
necessary for the exchange in question, (b) to fill in the number of shares 
being transferred and (c) to deliver same, together with the certificates 
evidencing shares to be transferred to Summit and such other Holder, as the 
case may be.

     3.   The Holders irrevocably authorize the Company to deposit with you 
any certificates evidencing the Shares to be held by you hereunder and any 
additions and substitutions to the Shares.  Concurrently with such deposit, 
each Holder shall deposit with you a signed Instrument of Transfer and signed 
Bought and Sold Note, together with any other instruments required to effect 
the transfer of the Shares.  Each Holder does hereby irrevocably constitute 
and appoint you as such Holder's attorney-in-fact and agent for the term of 
this escrow to execute with respect to such securities and other property all 
documents of assignment and/or transfer and all stock certificates necessary 
or 


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appropriate to make all securities negotiable and to complete any transaction 
herein contemplated.

     4.   This escrow shall terminate upon expiration or exercise of the 
Exchange Right, whichever occurs first. 

     5.   If at the time of termination of this escrow you should have in 
your possession any documents, securities, or other property belonging to 
either Holder, you shall deliver all of same to such Holder, and you shall be 
discharged of all further obligations hereunder.

     6.   Your duties hereunder may be altered, amended, modified, or revoked 
only by a writing signed by all of the parties hereto.

     7.   You shall be obligated only for the performance of the duties 
specifically set forth herein and may rely and shall be protected in relying 
or refraining from acting on any instrument reasonably believed by your to be 
genuine and to have been signed or presented by the proper party or parties 
or their assignees.  You shall not be personally liable for any act you may 
do or omit to do hereunder as Escrow Agent or as attorney-in-fact for any 
Holder while acting in good faith, and any act done or omitted by you 
pursuant to the advice of your own attorneys shall be conclusive evidence of 
such good faith.

     8.   You are hereby expressly authorized to disregard any and all 
warnings given by any of the parties hereto or by any other person or 
corporation, excepting only orders or process of courts of law, and are 
hereby expressly authorized to comply with and obey orders, judgments, or 
decrees of any court. In case you obey or comply with any such order, 
judgment, or decree of any court, you shall not be liable to any of the 
parties hereto or to any other person, firm, or corporation by reason of such 
compliance, notwithstanding any such order, judgment, or decree being 
subsequently reversed, modified, annulled, set aside, vacated, or found to 
have been entered without jurisdiction.

     9.   You shall not be liable in any respect on account of the identity, 
authority, or rights of the parties executing or delivering or purporting to 
execute or deliver the Agreement or any documents or papers deposited or 
called for hereunder.

     10.  Your responsibilities as Escrow Agent hereunder shall terminate if 
you shall resign by written notice to each party.  In the event of any such 
termination, the Company may appoint any person reasonably satisfactory to 
each Holder as successor Escrow Agent, and the Holders hereby confirm the 
appointment of such successor or successors as each Holder's attorney-in-fact 
and agent to the full extent of your appointment.


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     11.  If you reasonably require other for further instruments in 
connection with these Joint Escrow Instructions or obligations in respect 
hereto, the necessary parties hereto shall join in furnishing such 
instruments.

     12.  It is understood and agreed that should any dispute arise with 
respect to the delivery and/or ownership or right of possession of the 
securities, you may (but are not obligated to) retain in your possession, 
without liability to anyone, all or any part of said securities until such 
dispute shall have been settled either by mutual written agreement of the 
parties concerned or by a final order, decree, or judgment of a court of 
competent jurisdiction after the time for appeal has expired and no appeal 
has been perfected, but you shall be under no duty whatsoever to institute or 
defend any such proceedings.

     13.  Any notice required or permitted hereunder shall be given in 
writing and shall be deemed effectively given upon personal delivery to the 
party to be notified, on the fifth day after deposit with the United States 
Postal Service, by registered or certified mail, postage prepaid, or upon 
confirmation if sent by telex, facsimile machine for other means of 
telecommunication that transmits or produces a written record of the message 
so sent or at such other addresses as a party may designate by ten days' 
written notice to each of the other parties hereto:

<TABLE>
<CAPTION>

   <S>                     <C>
     IF TO THE COMPANY:       Summit Design Asia, Ltd.
                              Suite 704, Tower 2, Silvercord
                              Canton Road, T.S.T. Hong Kong

     IF TO SUMMIT:            Summit Design, Inc.
                              9305 S.W. Gemini Drive
                              Beaverton, OR  97008
                              USA
                              Attention:  Larry Gerhard
                              Fax No.  503-646-9320

     IF TO ANAM:              Anam S&T
                              3rd Floor Anam Building
                              154-17 Samsung-Dong, Kangnam-Ku
                              Seoul Korea  135090
                              Attention:  Stephen Kim
                              Fax No.  852-2810-5994

     IF TO ESCROW AGENT:      Perkins Coie (Hong Kong) Limited
                              23rd Floor
                              Asia Pacific Finance Tower
                              Citibank Plaza, 3 Garden Road
                              Hong Kong

</TABLE>


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     14.  By signing these Joint Escrow Instructions you become a party 
hereto only for the purpose of said Joint Escrow Instructions and not a party 
to the Agreement.

     15.  This instrument shall be binding upon and inure to the benefit of 
the parties hereto and their respective successors and permitted assigns.  It 
is understood and agreed that references to "you" or "your" herein refer to 
the original Escrow Agent and to any and all successor Escrow Agents.  

                                   SUMMIT DESIGN ASIA, LTD., a Hong Kong
                                      corporation
          
                                   By:  /s/ K.H. Kwon        
                                      --------------------------------------
                                   Name: Ki Hong Kwon
                                   Title:   Director


                                   HOLDERS:

                                   SUMMIT DESIGN, INC.


                                   By:  /s/ C.Albert Koob    
                                      --------------------------------------
                                   Name:  C. Albert Koob
                                   Title:    Chief Financial Officer
                                   
                                   ANAM S&T CO., LTD.
                                   
                                   
                                   By:  /s/ Stephen M. Kim   
                                      --------------------------------------
                                   Name: Stephen M. Kim
                                   Title: President

ESCROW AGENT:

PERKINS COIE (HONG KONG) LIMITED



By:                      
   --------------------------------
Name:
Title:


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