<PAGE>
                                                                    EXHIBIT 10.1

                               SUPPORT AGREEMENT

  MEMORANDUM OF AGREEMENT made as of the 16th day of March, 1999

BETWEEN:
                  AUTODESK, INC.,
                  a corporation subsisting under the laws
                  of the State of Delaware,

                  (hereinafter referred to as the "Parent"),

                  --and--

                  AUTODESK DEVELOPMENT B.V.,
                  a corporation subsisting under the laws
                  of The Netherlands,

                  (hereinafter referred to as "Dutchco"),

                  --and--

                  DISCREET LOGIC INC.,
                  a corporation subsisting under the laws
                  of the Province of Quebec,

                  (hereinafter referred to as the "Corporation").

  WHEREAS pursuant to the Second Amended and Restated Agreement and Plan of
Acquisition and Amalgamation dated as of November 18, 1998, as amended, by and
among the Parent, Dutchco, 9066-9771 Quebec Inc. ("Amalgamation Sub"), Autodesk
Canada Inc. ("ACI") 9066-9854 Quebec Inc. ("Autodesk Quebec") and Discreet Logic
Inc. (a predecessor to the Corporation) (such agreement being hereinafter
referred to as the "Combination Agreement"), the parties agreed that immediately
after the Effective Time (as such term is defined in the Combination Agreement),
the Parent, Dutchco and the Corporation would execute and deliver a Support
Agreement containing the terms and conditions set forth in Exhibit C to the
Combination Agreement, together with such other terms and conditions as may be
agreed to by the parties to the Combination Agreement acting reasonably;

  AND WHEREAS pursuant to the Combination Agreement, articles of amalgamation
dated March 16, 1999 (the "Articles of Amalgamation") were filed pursuant to the
Companies Act (Quebec) whereby Discreet Logic Inc., Autodesk Quebec and
Amalgamation Sub amalgamated to continue as the Corporation;

  AND WHEREAS immediately following to the Amalgamation, holders of certain
issued and outstanding Class B non-voting common share of the Corporation (the
"Class B Shares") elected to retract such shares in exchange for Exchangeable
Non-Voting Shares of the Corporation (the "Exchangeable Shares") on the basis of
0.33 of an Exchangeable Share for each Class B Share so retracted;

  AND WHEREAS the Articles of Amalgamation set forth the rights, privileges,
restrictions and conditions (collectively, the "Exchangeable Share Provisions")
attaching to the Exchangeable Shares;

                                       1
<PAGE>

  AND WHEREAS pursuant to the Transactions (as defined in the Combination
Agreement), Dutchco, an indirect wholly owned subsidiary of the Parent, is the
registered and beneficial owner of all of the issued and outstanding Class A
Shares of the Corporation and all of the issued and outstanding Class E Shares
and Class F Shares of the Corporation, and ACI, a wholly owned subsidiary of the
Parent, is the registered and beneficial owner of all of the issued and
outstanding Class C Shares of the Corporation, U.S. Bancorp Piper Jaffray Inc.
is the registered and beneficial owner of 112,500 of the issued and outstanding
Class D Shares of the Corporation and Aird & Berlis is the registered and
beneficial owner of 37,500 of the issued and outstanding Class D Shares of the
Corporation;

  AND WHEREAS the parties hereto desire to make appropriate provision and to
establish a procedure whereby the Parent and Dutchco will take certain actions
and make certain payments and deliveries necessary to ensure that the
Corporation will be able to make certain payments and to deliver or cause to be
delivered, Parent Common Shares in satisfaction of the obligations of the
Corporation under the Exchangeable Share Provisions with respect to the payment
and satisfaction of Liquidation Amounts, Retraction Prices and Redemption
Prices, all in accordance with the Exchangeable Share Provisions;

  NOW THEREFORE in consideration of the respective covenants and agreements
provided in this agreement and for other good and valuable consideration (the
receipt and sufficiency of which are hereby acknowledged), the parties agree as
follows:

                                   ARTICLE 1

                         DEFINITIONS AND INTERPRETATION

  1.1 Defined Terms. Each term denoted herein by initial capital letters and not
otherwise defined herein shall have the meaning ascribed thereto in the
Exchangeable Share Provisions, unless the context requires otherwise.

  1.2 Interpretation not Affected by Headings, etc. The division of this
agreement into articles, sections and paragraphs and the insertion of headings
are for convenience of reference only and shall not affect the construction or
interpretation of this agreement.

  1.3 Number, Gender, etc. Words importing the singular number only shall
include the plural and vice versa. Words importing the use of any gender shall
include all genders.

  1.4 Date for any Action. In the event that any date on or by which any action
is required or permitted to be taken under this agreement is not a Business Day,
such action shall be required or permitted to be taken on or by the next
succeeding Business Day. For the purposes of this agreement, a "Business Day"
means any day other than a Saturday, Sunday or a day when banks are not open for
business in either or both of San Francisco, California or Montreal, Quebec.

                                   ARTICLE 2

              COVENANTS OF THE PARENT, DUTCHCO AND THE CORPORATION

  2.1 Funding of the Corporation. So long as any Exchangeable Shares are
outstanding, the Parent (and Dutchco in the case of subclauses (b), (e) and (f))
will:

  (a) not declare or pay any dividend on the Parent Common Shares unless (i) the
Corporation will have sufficient assets, funds and other property available to
enable the due declaration and the due and punctual payment in accordance with
applicable law, of an equivalent dividend on the Exchangeable Shares and (ii)
the Corporation shall simultaneously declare or pay, as the case may be, an
equivalent dividend on the Exchangeable Shares, in each case in accordance with
the Exchangeable Share Provisions;

                                       2
<PAGE>

  (b) cause the Corporation to declare simultaneously with the declaration of
any dividend on the Parent Common Shares an equivalent dividend on the
Exchangeable Shares and, when such dividend is paid on the Parent Common Shares,
cause the Corporation to pay simultaneously therewith such equivalent dividend
on the Exchangeable Shares, in each case in accordance with the Exchangeable
Share Provisions;

  (c) advise the Corporation sufficiently in advance of the declaration by the
Parent of any dividend on the Parent Common Shares and take all such other
actions as are necessary, in cooperation with the Corporation, to ensure that
the respective declaration date, record date and payment date for a dividend on
the Exchangeable Shares shall be the same as the record date, declaration date
and payment date for the corresponding dividend on the Parent Common Shares and
shall correspond with any required dating for any stock exchange purpose on
which the Exchangeable Shares are listed;

  (d) ensure that the record date for any dividend declared on the Parent Common
Shares is not less than 10 Business Days after the declaration date for such
dividend;

  (e) take all such actions and do all such things as are necessary or desirable
to enable and permit the Corporation, in accordance with applicable law, to pay
and otherwise perform its obligations with respect to the satisfaction of the
Liquidation Amount in respect of each issued and outstanding Exchangeable Share
upon the liquidation, dissolution or winding-up of the Corporation, including
without limitation all such actions and all such things as are necessary or
desirable to enable and permit the Corporation to cause to be delivered Parent
Common Shares to the holders of Exchangeable Shares in accordance with the
provisions of Article 5 of the Exchangeable Share Provisions; and

  (f) take all such actions and do all such things as are necessary or desirable
to enable and permit the Corporation, in accordance with applicable law, to pay
and otherwise perform its obligations with respect to the satisfaction of the
Retraction Price and the Redemption Price, including without limitation all such
actions and all such things as are necessary or desirable to enable and permit
the Corporation to cause to be delivered Parent Common Shares to the holders of
Exchangeable Shares, upon the redemption of the Exchangeable Shares in
accordance with the provisions of Article 6 or Article 7 of the Exchangeable
Share Provisions, as the case may be.

  2.2 Segregation of Funds. The Parent will and if applicable will cause the
Corporation to deposit a sufficient amount of funds in a separate account and
segregate a sufficient amount of such assets and other property as is necessary
to enable the Corporation to pay or otherwise satisfy the applicable Liquidation
Amount, Retraction Price or Redemption Price, in each case for the benefit of
holders from time to time of the Exchangeable Shares, and will use such funds,
assets and other property so segregated exclusively for the payment or other
satisfaction of the Liquidation Amount, the Retraction Price or the Redemption
Price, as applicable.

  2.3 Reservation of Parent Common Shares. The Parent hereby represents,
warrants and covenants that it has irrevocably reserved for issuance and will at
all times keep available, free from pre-emptive and other rights, out of its
authorized and unissued capital stock such number of Parent Common Shares (or
other shares or securities into which the Parent Common Shares may be
reclassified or changed as contemplated by section 2.7 hereof) (a) as is equal
to the sum of (i) the number of Exchangeable Shares issued and outstanding from
time to time and (ii) the number of Exchangeable Shares issuable upon the
exercise of all rights to acquire Exchangeable Shares outstanding from time to
time and (b) as are now and may hereafter be required to enable and permit the
Corporation to meet its obligations hereunder, under the Voting and Exchange
Trust Agreement, under the Exchangeable Share Provisions and under any other
security or commitment pursuant to which the Parent may now or hereafter be
required to issue Parent Common Shares.

  2.4 Notification of Certain Events. In order to assist the Parent and Dutchco
to comply with their obligations hereunder, the Corporation will give the Parent
and Dutchco notice of each of the following events at the time set forth below:

  (a) in the event of any determination by the Board of Directors of the
Corporation to institute voluntary liquidation, dissolution or winding up
proceedings with respect to the Corporation or to effect any other distribution
of the assets of the Corporation among its shareholders for the purpose of
winding up its affairs, at least 60 days prior to the proposed effective date of
such liquidation, dissolution, winding up or other distribution;

  (b) immediately, upon the earlier of receipt by the Corporation of notice of
and the Corporation otherwise becoming aware of any threatened or instituted
claim, suit, petition or other proceeding with respect to the involuntary
liquidation,

                                       3
<PAGE>

dissolution or winding up of the Corporation or to effect any other
distribution of the assets of the Corporation among its shareholders for the
purpose of winding up its affairs;

  (c) immediately, upon receipt by the Corporation of a Retraction Request (as
defined in the Exchangeable Share Provisions);

  (d) at least 130 days prior to any accelerated Automatic Redemption Date
determined by the Board of Directors of the Corporation in accordance with the
Exchangeable Share Provisions; and

  (e) as soon as practicable upon the issuance by the Corporation of any
Exchangeable Shares or rights to acquire Exchangeable Shares (other than the
issuance of Exchangeable Shares upon the redemption of outstanding Class B
Shares pursuant to the Transactions).

  2.5 Delivery of Parent Common Shares. In furtherance of its obligations under
sections 2.1(e) and 2.1(f) hereof, upon notice from the Corporation of any event
which requires the Corporation to cause to be delivered Parent Common Shares to
any holder of Exchangeable Shares, Dutchco shall forthwith deliver the requisite
Parent Common Shares to or to the order of the former holder of the surrendered
Exchangeable Shares, as the Corporation shall direct. All such Parent Common
Shares shall be duly issued as fully paid and non-assessable and shall be free
and clear of any lien, claim, encumbrance, security interest or adverse claim.
In consideration of the delivery of each such Parent Common Share by Dutchco,
the Corporation shall issue to Dutchco, or as Dutchco shall direct, such number
of Class A Shares of the Corporation as is equal to the fair value of such
Parent Common Share.

  2.6 Qualification of Parent Common Shares in the United States. The Parent
represents and warrants that it has taken all actions and done all things as are
necessary or desirable to cause the Parent Common Shares to be issued and
delivered pursuant to the Exchangeable Share Provisions, the Exchange Right or
the Automatic Exchange Rights (as defined in the Voting and Exchange Trust
Agreement) to be freely tradeable thereafter in the United States (other than
any restrictions on transfers by reason of a holder being an "affiliate" of the
Parent or, prior to the Effective Date, for purposes of United States federal or
state securities law). The Parent will in good faith expeditiously take all such
actions and do all such things as are necessary or desirable to cause all Parent
Common Shares to be delivered pursuant to the Exchangeable Share Provisions,
Exchange Right or the Automatic Exchange Rights to be listed, quoted or posted
for trading on all stock exchanges and quotation systems on which outstanding
Parent Common Shares are listed, quoted or posted for trading at such time.

  2.7 Economic Equivalence.

  (a) The Parent will not without the prior approval of the Corporation and the
prior approval of the holders of the Exchangeable Shares given in accordance
with Section 10.2 of the Exchangeable Share Provisions:

     (i) issue or distribute Parent Common Shares (or securities exchangeable
  for or convertible into or carrying rights to acquire Parent Common Shares) to
  the holders of all or substantially all of the then outstanding Parent Common
  Shares by way of stock dividend or other distribution, other than an issue of
  Parent Common Shares (or securities exchangeable for or convertible into or
  carrying rights to acquire Parent Common Shares) to holders of Parent Common
  Shares who exercise an option to receive dividends in Parent Common Shares (or
  securities exchangeable for or convertible into or carrying rights to acquire
  Parent Common Shares) in lieu of receiving cash dividends; or

     (ii) issue or distribute rights, options or warrants to the holders of all
  or substantially all of the then outstanding Parent Common Shares entitling
  them to subscribe for or to purchase Parent Common Shares (or securities
  exchangeable for or convertible into or carrying rights to acquire Parent
  Common Shares); or

     (iii) issue or distribute to the holders of all or substantially all of the
  then outstanding Parent Common Shares (A) shares or securities of the Parent
  of any class other than Parent Common Shares (other than shares convertible
  into or exchangeable for or carrying rights to acquire Parent Common Shares),
  (B) rights, options or warrants other than those referred to in section
  2.7(a)(ii) above, (C) evidences of indebtedness of the Parent or (D) assets of
  the Parent;

                                       4
<PAGE>

unless (i) the Corporation is able under applicable law to issue or distribute
the economic equivalent on a per share basis of such rights, options,
securities, shares, evidences of indebtedness or other assets simultaneously to
holders of the Exchangeable Shares, and (ii) the Corporation shall issue or
distribute such rights, options, securities, shares, evidences of indebtedness
or other assets simultaneously to holders of the Exchangeable Shares.

  (b) The Parent will not without the prior approval of the Corporation and the
prior approval of the holders of the Exchangeable Shares given in accordance
with Section 10.2 of the Exchangeable Share Provisions:

     (i) subdivide, redivide or change the then outstanding Parent Common Shares
  into a greater number of Parent Common Shares; or
     (ii) reduce, combine or consolidate or change the then outstanding Parent
  Common Shares into a lesser number of Parent Common Shares; or

     (iii) reclassify or otherwise change the Parent Common Shares or effect an
  amalgamation, merger, reorganization or other transaction affecting the Parent
  Common Shares;

unless (i) the Corporation is able under applicable law to simultaneously make
the same or an economically equivalent change to, or in the rights of the
holders of, the Exchangeable Shares, and (ii) the Corporation simultaneously
does make the same or an economically equivalent change to, or in the rights of
the holders of, the Exchangeable Shares.

  (c) The Parent will ensure that the record date for any event referred to in
section 2.7(a) or 2.7(b) above, or (if no record date is applicable for such
event) the effective date for any such event, is not less than 20 Business Days
(or such shorter period as the Parent and the Corporation may agree upon) after
the date on which such event is declared or announced by the Parent (with
simultaneous notice thereof to be given by the Parent to the Corporation).

  (d) The Board of Directors of the Corporation shall determine, in good faith
and in its sole discretion (with the assistance of such reputable and qualified
independent financial advisors and/or other experts as the board may require),
economic equivalence for the purposes of any event referred to in Section 2.7(a)
or 2.7(b) above and each such determination shall be conclusive and binding on
Dutchco and the Parent. In making each such determination, the following factors
shall, without excluding other factors determined by the Board of Directors of
the Corporation to be relevant, be considered by the Board of Directors of the
Corporation:

     (i) in the case of any stock dividend or other distribution payable in
  Parent Common Shares, the number of such shares issued in proportion to the
  number of Parent Common Shares previously outstanding;

     (ii) in the case of the issuance or distribution of any rights, options or
  warrants to subscribe for or purchase Parent Common Shares (or securities
  exchangeable for or convertible into or carrying rights to acquire Parent
  Common Shares), the relationship between the exercise price of each such
  right, option or warrant and the current market value (as determined by the
  Board of Directors of the Corporation in the manner above contemplated) of a
  Parent Common Share;

     (iii) in the case of the issuance or distribution of any other form of
  property (including without limitation any shares or securities of the Parent
  of any class other than Parent Common Shares, any rights, options or warrants
  other than those referred to in Section 2.7(d)(ii) above, any evidences of
  indebtedness of the Parent or any assets of the Parent), the relationship
  between the fair market value (as determined by the Board of Directors of the
  Corporation in the manner above contemplated) of such property to be issued or
  distributed with respect to each outstanding Parent Common Share and the
  current market value (as determined by the Board of Directors of the
  Corporation in the manner above contemplated) of a Parent Common Share;

     (iv) in the case of any subdivision, redivision or change of the then
  outstanding Parent Common Shares into a greater number of Parent Common Shares
  or the reduction, combination or consolidation or change of the then
  outstanding Parent Common Shares into a lesser number of Parent Common Shares
  or any amalgamation, merger, reorganization or other transaction affecting the
  Parent Common Shares, the effect thereof upon the then outstanding Parent
  Common Shares; and

                                       5
<PAGE>

     (v) in all such cases, the general taxation consequences of the relevant
  event to holders of Exchangeable Shares to the extent that such consequences
  may differ from the taxation consequences to holders of Parent Common Shares
  as a result of differences between taxation laws of Canada and the United
  States (except for any differing consequences arising as a result of differing
  marginal taxation rates and without regard to the individual circumstances of
  holders of Exchangeable Shares).

  For purposes of the foregoing determinations, the current market value of any
security listed and traded or quoted on a securities exchange or automated
quotation system shall be the average of the closing prices of such security
during the three consecutive trading days ending not more than five trading days
before the date of determination on the principal securities exchange on which
such securities are listed and traded or quoted; provided, however, that if
there is no active public distribution or trading activity of such securities
during such period, then the current market value thereof shall be determined by
the Board of Directors of the Corporation, in good faith and in its sole
discretion (with the assistance of such reputable and qualified independent
financial advisors and/or other experts as the board may require), and provided
further that any such determination by the Board of Directors of the Corporation
shall be conclusive and binding on the Parent.

  2.8 Tender Offers, Etc. In the event that a tender offer, share exchange
offer, issuer bid, take-over bid or similar transaction with respect to Parent
Common Shares (an "Offer") is proposed by the Parent or is proposed to the
Parent or its shareholders and is recommended by the Board of Directors of the
Parent, or is otherwise effected or to be effected with the consent or approval
of the Board of Directors of the Parent, the Parent will use its best efforts
expeditiously and in good faith to take all such actions and do all such things
as are necessary or desirable to enable and permit holders of Exchangeable
Shares to participate in such Offer to the same extent and on an economically
equivalent basis as the holders of Parent Common Shares, without discrimination.
Without limiting the generality of the foregoing, the Parent will use its best
efforts expeditiously and in good faith to ensure that holders of Exchangeable
Shares may participate in all such Offers without being required to retract
Exchangeable Shares as against the Corporation (or, if so required, to ensure
that any such retraction shall be effective only upon, and shall be conditional
upon, the closing of the Offer and only to the extent necessary to tender or
deposit to the Offer).

  2.9 Ownership of Outstanding Shares. Without the prior approval of the
Corporation and the prior approval of the holders of the Exchangeable Shares
given in accordance with Section 10.2 of the Exchangeable Share Provisions, the
Parent covenants and agrees in favour of the Corporation that, as long as any
outstanding Exchangeable Shares are owned by any person or entity other than the
Parent or any of its Affiliates, Parent will be and remain the direct or
indirect beneficial owner of all issued and outstanding shares in the capital of
the Corporation other than the Class D Shares and all outstanding securities of
the Corporation, in each case carrying or otherwise entitled to voting rights in
any circumstances, and in each case other than the Exchangeable Shares or the
Class D Shares.

  2.10 Parent Not To Vote Exchangeable Shares. The Parent covenants and agrees
that it will appoint and cause to be appointed proxyholders with respect to all
Exchangeable Shares held by the Parent and its subsidiaries and Affiliates for
the sole purpose of attending each meeting of holders of Exchangeable Shares in
order to be counted as part of the quorum for each such meeting. The Parent
further covenants and agrees that it will not, and will cause its subsidiaries
and Affiliates not to, exercise any voting rights which may be exercisable by
holders of Exchangeable Shares from time to time pursuant to the Exchangeable
Share Provisions or pursuant to the provisions of the Companies Act (Quebec) (or
any successor or other corporate statute by which the Corporation in the future
shall be governed) with respect to any Exchangeable Shares held by it or by its
subsidiaries or Affiliates in respect of any matter considered at any meeting of
holders of Exchangeable Shares.

  2.11 Due Performance. On and after the Effective Time, Parent and Dutchco
shall duly and timely perform all of their respective obligations expressed in
the Combination Agreement.

  2.12 Preservation of Existence of Corporation. Without the prior approval of
the holders of Exchangeable Shares given in accordance with Section 10.2 of the
Exchangeable Shares Provisions, the Parent, Dutchco and Corporation covenant and
agree that, so long as any Exchangeable Shares are owned by any person or entity
other than the Parent or its Affiliates, the separate existence of Corporation
shall be preserved and Corporation shall not be liquidated, wound up or
dissolved or merged with or into another entity.

                                       6
<PAGE>

  2.13 Certain Requirements in Respect of Combination, etc. The Parent shall not
enter into any transaction (whether by way of reconstruction, reorganization,
consolidation, merger, transfer, sale, lease or otherwise) whereby all or
substantially all of its undertaking, property and assets would become the
property of any other person or, in the case of a merger, of the continuing
corporation resulting therefrom unless:

  (a) such other person or continuing corporation is a corporation (herein
called the "Parent Successor") incorporated under the laws of any state of the
United States or the laws of Canada or any province thereof;

  (b) the Parent Successor, by operation of law, becomes, without more, bound by
the terms and provisions of this trust agreement or, if not so bound, executes,
prior to or contemporaneously with the consummation of such transaction a trust
agreement supplemental hereto and such other instruments (if any) as are
satisfactory to the Trustee and in the opinion of legal counsel to the Trustee
are necessary or advisable to evidence the assumption by the Parent Successor of
liability for all moneys payable and property deliverable hereunder and the
covenant of such Parent Successor to pay and deliver or cause to be delivered
the same and its agreement to observe and perform all the covenants and
obligations of the Parent under this trust agreement; and

  (c) such transaction shall, to the satisfaction of the Trustee and in the
opinion of legal counsel to the Trustee, be upon such terms as substantially to
preserve and not to impair in any material respect any of the rights, duties,
powers and authorities of the Trustee or of the Beneficiaries hereunder.

                                   ARTICLE 3

                                    GENERAL

  3.1 Term. This agreement shall come into force and be effective upon the issue
by the Corporation of Exchangeable Shares and shall terminate and be of no
further force and effect at such time as no Exchangeable Shares (or securities
or rights convertible into or exchangeable for or carrying rights to acquire
Exchangeable Shares) are held by any party other than the Parent and any of its
Affiliates.

  3.2 Changes in Capital of Parent and the Corporation. Notwithstanding the
provisions of Section 3.4, at all times after the occurrence of any event
effected pursuant to Section 2.7 or 2.8 hereof, as a result of which either the
Parent Common Shares or the Exchangeable Shares or both are in any way changed,
this agreement shall forthwith be amended and modified as necessary in order
that it shall apply with full force and effect, mutatis mutandis, to all new
securities into which the Parent Common Shares or the Exchangeable Shares or
both are so changed and the parties hereto shall execute and deliver an
agreement in writing giving effect to and evidencing such necessary amendments
and modifications.

  3.3 Severability. If any provision of this agreement is held invalid, illegal
or unenforceable, the validity, legality or enforceability of the remainder of
this agreement shall not in any way be affected or improved thereby and this
agreement shall be carried and as near as possible in accordance with its
original terms and conditions; and to this end the provisions of this agreement
are intended to be and shall be deemed severable; provided, however, that if the
provision or provisions so held to be invalid, in the reasonable judgment of the
parties hereto, is or are so fundamental to the intent of the parties hereto and
the operation of this agreement that the enforcement of the other provisions
hereof, in the absence of such invalid provision or provisions, would damage
irreparably the intent of the parties in entering into this agreement, the
parties hereto shall agree to amend or otherwise modify this agreement so as to
carry out the intent and purposes hereof and the transactions contemplated
hereby.

  3.4 Amendments, Modifications, etc. Except as contemplated by Section 3.5,
this agreement may not be amended or modified except by an agreement in writing
executed by the Corporation, Dutchco and the Parent and approved by the holders
of the Exchangeable Shares in accordance with Section 10.2 of the Exchangeable
Share Provisions.

  3.5 Ministerial Amendments. Notwithstanding the provisions of Section 3.4, the
parties to this agreement may in writing, at any time and from time to time,
without the approval of the holders of the Exchangeable Shares, amend or modify
this agreement for the purposes of:

                                       7
<PAGE>

  (a) adding to the covenants of any of the parties for the protection of the
holders of the Exchangeable Shares;

  (b) making such amendments or modifications not inconsistent with this
agreement as may be necessary or desirable with respect to matters or questions
which, in the opinion of the Boards of Directors of each of the Corporation,
Dutchco and the Parent, it may be expedient to make, provided that each such
Board of Directors shall be of the opinion that such amendments or modifications
will not be prejudicial to the interests of the holders of the Exchangeable
Shares; or

  (c) making such changes or corrections which, on the advice of counsel to the
Corporation, Dutchco and the Parent, are required for the purpose of curing or
correcting any ambiguity or defect or inconsistent provision or clerical
omission or mistake or manifest error, provided that the Boards of Directors of
each of the Corporation, Dutchco and the Parent shall be of the opinion that
such changes or corrections will not be prejudicial to the interests of the
holders of the Exchangeable Shares.

  3.6 Meeting to Consider Amendments. The Corporation, at the request of the
Parent or Dutchco, shall call a meeting or meetings of the holders of the
Exchangeable Shares for the purpose of considering any proposed amendment or
modification requiring approval pursuant to Section 3.4 hereof. Any such meeting
or meetings shall be called and held in accordance with the by-laws of the
Corporation, the Exchangeable Share Provisions and all applicable laws.

  3.7 Amendments Only in Writing. No amendment to or modification or waiver of
any of the provisions of this agreement otherwise permitted hereunder shall be
effective unless made in writing and signed by all of the parties hereto.

  3.8 Enurement. This agreement shall be binding upon and enure to the benefit
of the parties hereto and their respective successors and assigns.

  3.9 Notices to Parties. All notices and other communications between the
parties shall be in writing and shall be deemed to have been given if delivered
personally or by confirmed telecopy to the parties at the following addresses
(or at such other address for either such party as shall be specified in like
notice):

  (a) if to the Parent or Dutchco at:

     Autodesk, Inc.
     20400 Stevens Creek Boulevard
     Cupertino, CA 95401-2217
     Attention: Marcia K. Sterling
      Vice President Business Development, General Counsel and Secretary
     Telecopy:
       (408) 517-1886

  (b) if to the Corporation at:

     Discreet Logic Inc.
     10 Duke Street
     Montreal, Quebec
     Canada H3C 2L7
     Attention: Francois Plamondon
       Senior Vice President, Chief Financial Officer, Treasurer and Secretary
     Telecopy:
       (514) 393-3996

Any notice or other communication given personally shall be deemed to have been
given and received upon delivery thereof and if given by telecopy shall be
deemed to have been given and received on the date of confirmed receipt thereof,
provided such notice or other communication is received prior to 5:00 p.m.
(local time) on a Business Day, and otherwise it shall be deemed to have been
given and received upon the immediately following Business Day.

                                       8
<PAGE>

  3.10 Counterparts. This agreement may be executed in counterparts, each of
which shall be deemed an original, and all of which taken together shall
constitute one and the same instrument.

  3.11 Jurisdiction. This agreement shall be construed and enforced in
accordance with the laws of the Province of Quebec and the laws of Canada
applicable therein.

  3.12 Attornment. The Parent, Dutchco and the Corporation agree that any action
or proceeding arising out of or relating to this agreement may be instituted in
the courts of Quebec, waive any objection which they may have now or hereafter
to the venue of any such action or proceeding, irrevocably submits to the non-
exclusive jurisdiction of the said courts in any such action or proceeding,
agree to be bound by any judgment of the said courts and not to seek, and hereby
waive, any review of the merits of any such judgment by the courts of any other
jurisdiction and the Parent and Dutchco hereby appoint the Corporation at its
registered office in the Province of Quebec as the Parent's and Dutchco's
attorney for service of process.

  3.13 Guaranty/Assignment. Parent hereby unconditionally and irrevocably
guarantees the prompt and full performance by Dutchco of, and shall cause
Dutchco to comply with, its obligations hereunder and pursuant to the
Transactions. Dutchco may assign all or a portion of its rights and obligations
hereunder to Parent or any Affiliate of Parent, which shall thereupon assume
such assigned rights and/or obligations without the consent of the Corporation
subject to the Corporation and Parent or such Affiliate, as the case may be,
entering into a supplemental agreement reflecting such assignment and
assumption. This agreement may not be assigned by the Parent without the prior
written consent of Dutchco and the Corporation approved by the holders of the
Exchangeable Shares in accordance with Section 10.2 of the Exchangeable Share
Provisions.

  3.14 Language. The parties have agreed that this agreement be drafted in
English. Les parties ont convenu que cette convention soit redigee en langue
anglaise.

                                       9
<PAGE>

  IN WITNESS WHEREOF, the parties hereto have caused this agreement to be duly
executed as of the date first above written.


                                  AUTODESK, INC.


                                  By:    /s/     Carol A. Bartz
                                     --------------------------
                                    Name:  Carol A. Bartz
                                    Title:  Chief Executive Officer


                                  AUTODESK DEVELOPMENT B.V.


                                  By:    /s/     Michael E. Sutton
                                     -----------------------------
                                    Name:  Michael E. Sutton
                                    Title:  Directeur

                                  DISCREET LOGIC INC.


                                  By:       /s/  Marcia K. Sterling
                                     ------------------------------
                                    Name:  Marcia K. Sterling
                                    Title:  Secretary

                                       10