Patent Publication Number: US-2011055583-A1

Title: Method for exchanging a 3d view between a first and a second user

Description:
FIELD OF THE INVENTION 
     The invention relates to a method for exchanging a 3D view created by a piece of software for creating 3D views. One of the aims of the invention is to allow a user to read a view created by another user that comprises an encrypted object. The piece of software is used to create outdoor or indoor views. The piece of software can be used in the field of architecture, illustration, or the creation of virtual images for movies or video games. 
     BACKGROUND OF THE INVENTION 
     The piece of software uses a license number which is provided to the user when he acquires a copy of the software, each license number being different from one copy of the software to another. Some objects such as trees, stones or basic buildings are provided to the user so that he can create 3D views. These objects are referred to as public objects. These public objects are provided with each copy of the software. Thus the views comprising public objects can be exchanged between different users of the software, i.e., a view created by a first user can be read by a second user. 
     Furthermore, encrypted objects such as a particular type of car or a particular type of building can be acquired separately by the user. These encrypted objects can only be read with the software license for which they have been encrypted. Each encrypted object is encrypted and can be deciphered by a key specific to the user&#39;s software license. This way if a first user creates a 3D view comprising an encrypted object for which he has acquired a license, a second user cannot read this view. As a matter of fact, the second user does not have the key to decipher the encrypted object of the first user, even if he is licensed for the same object. The reason is that, in order to avoid the users exchanging encrypted objects without acquiring a license for these objects, the keys used to decipher a given encrypted object are different from one software license to another. 
     A possible solution for exchanging views comprising encrypted objects would be to get the key of the second user, so that the first user can encrypt the view with this key. Then the second user would be able to read the view that has been encrypted with his key. 
     But this solution is not very safe because data that the users are not supposed to access (i.e. the keys of the encrypted objects) would be exchanged between the users. Furthermore, the encrypted view can be read only by a particular user (the one for which the view has been encrypted), but not by all the users having a license for the encrypted objects of the view. Moreover it is not possible to be sure that the second user sending the key to the first user has a license for the encrypted object of the view. 
     One of the aims of the invention is to allow the exchange of a view comprising an encrypted object, while minimizing the risk of use of objects by unauthorized users. 
     SUMMARY OF THE INVENTION 
     To achieve this aim, non-encrypted data defining the encrypted object is added in parallel with the encrypted data of the object sent to the second user, so that the second user can see a part or the whole object whether he is licensed or not for the encrypted object. 
     According to the invention, an object can be an element of the 3D view such as a stone, a tree, a building, a lake or an animal. However, an object can also be an image, a method for positioning elements in the view, a method for modifying the position of the elements in the view, a filter for modifying the aspect of an element of the view, a method for modifying the lighting of the view, a method for limiting the size of a stored view . . . 
     In fact an object according to the invention can be any extension content that the user can acquire separately from the software, this extension content having a technical and/or an esthetical feature. 
     In case the second user does not have a license for the encrypted object used in the view created by the first user, the second user can see and modify the public objects (to which he has access) but he cannot see the encrypted object for which he is not licensed. 
     In this case, the encrypted object is replaced by a dummy object which indicates where the encrypted object is located in the view. To achieve this, non-encrypted data defining the basic shape of the encrypted object is stored when the view is saved. This non-encrypted data can be the size, the location in the 3D view, the name of the encrypted object, and optionally the material of this object, or a basic representation of the object. In other words, the dummy object is defined by the minimum parameters needed by the user to identify an object in a 3D view. 
     If the second user (the one who is not licensed for the encrypted object) modifies the view created by the first user and saves the view, the first user (the one who is licensed for the encrypted object) will be able to see the whole 3D view, i.e. the modifications made by the first user but also the encrypted object for which he is licensed. 
     In case both users have a license for the encrypted object, they can exchange the view as if they had the same license for the object. To achieve this, the encrypted object is encrypted with a generic key and not with the key specific to the user. This generic key is unique for a given object, but different for each object. 
     In order to avoid the generic key to be known by the users, this generic key is encrypted with the specific key of the users associated to the encrypted object. Thus in order to have access to the generic key associated to an encrypted object, a given user must first have access to a first key which is associated to the encrypted object for which he has acquired a license. Then this first key is used to decipher the generic key. 
     In order to identify the generic key which has been used to encrypt the object, non-encrypted data is added to the encrypted object. This non-encrypted data identifies an encrypted object in a unique way. Thus when the user reads the non-encrypted data, he can know whether he has or not the license (i.e. the key) permitting the access to the generic key. The non-encrypted data identifying the object can be a name of the object, a name of a file, or any other unique identifier produced by a method for identifying an object. 
     In a particular embodiment, in order to locate quickly the encrypted object, the location of the encrypted object in the memory of the user&#39;s computer is stored in a table. This table associates the encrypted object with its location in the memory of the user&#39;s computer. This table is updated each time the user acquires or uses a new encrypted object. 
     Thus the invention relates to a method for exchanging a 3D view between a first and a second user having both a copy of a software product for creating 3D views, the copies of the software having different license numbers, in which:
         a view is created by the first user, this view comprising an encrypted object, the first user being licensed for the encrypted object,   this view is stored in a file by the first user, the encrypted object being encrypted, the result of this encryption being stored as encrypted data in the file, wherein   non-encrypted data defining the encrypted object is stored in the file in parallel with the encrypted data relating to the encrypted object,   this non-encrypted data can be read by the second user, so that the second user can see the encrypted object if he has acquired a license for this object, or a basic representation of the encrypted object if he has not acquired a license for this object.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawings, where like numerals represent like components, in which: 
         FIG. 1  is a schematic of the exchange of a 3D view between a first user having the license for an encrypted object used in the view and a second user not having the license for the encrypted object; 
         FIG. 2  is a schematic of the exchange of a 3D view between a first and a second users being both licensed for the encrypted object of the view; 
         FIG. 3  is a schematic of a file establishing a link between an identifier of the encrypted object and the location of this object in the memory of the user&#39;s computer. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION 
     A first user and a second user have acquired a copy of a software  1  for creating 3D views. A license A has been provided to the first user and a license B has been provided to the second user. Licenses A and B of the first and second users are different. 
     A library  2  comprising different types of public objects, such as a first species of tree  3 , a second species of tree  4 , and a house  5 , has been provided with each copy of the software  1 . The first and the second user can use the public objects  3 - 5  of the library  2  to create 3D views. 
     Moreover, the first user has acquired an encrypted object  6  (a car), a key  7  to encrypt and decipher this object  6  being provided with this object  6 . The second user has not acquired the encrypted object  6 . 
     The first user creates a 3D view  8  comprising the objects  3 - 5  and the car  6 . The first user can modify the objects  3 - 5  of the view  8  with regard to the original ones. In order to share the view  8  with the second user, the first user saves  9  this view  8  in a file  10 . 
     This file  10  comprises public data  10 . 1  relating to the objects  3 - 5 . The file comprises also data  10 . 2  relating to the basic parameters of the encrypted object  6 , such as the size, the location, the name or the aspect of the encrypted object. These basic parameters define a dummy object  16  which has globally the same size and is located at the same place than the car  6  in the view  8 . The data  10 . 1  and  10 . 2  are not encrypted. The data  10 . 1  and  10 . 2  are public data for the users having a software license. 
     The file  10  comprises also encrypted data  10 . 3  relating to the details of the object  6  such as the color, the material or the different volumes composing the object  6 . This data  10 . 3  has been encrypted with the key  7  associated to the object  6  or with a generic key (see  FIG. 2 ). 
     The file  10  is sent  15  to the second user who reads it. The second user can read the data  10 . 1  because it is not encrypted (the objects  3 - 5  are public). So the second user can see the objects  3 - 5  and the possible modifications made to these objects by the first user in the view  8 . 
     However, the second user cannot read the encrypted data  10 . 3  because he does not have the key  7  to decipher this data. So the second user cannot see the details of the car  6  in the view  8 . 
     But the second user can read the non-encrypted data  10 . 2  relating to the basic parameters of the car  6 . So the second user can see the dummy object  16  in the view  8 . This dummy object  16  replaces the car  6  and indicates that an encrypted object has been used to create the view  8 . 
     If the second user modifies the view  8  by adding a window  17  to the house  5  and saves  18  the modified view, the first user will be able to see the whole 3D view, including the modifications made by the second user (the window  17 ) and the car  6  that he can decipher with his key  7 . Moreover, the second user can modify certain properties of the dummy object  16  such as, for instance, its size or its location, so that the first user will be able to see the modifications of the dummy object made by the second user. 
     To achieve this, the modifications made by the second user are saved with the public data  10 . 1  or  10 . 2 . The encrypted data that the second user could not read is saved in the file as encrypted data  10 . 3  by the second user, the software having not modified the encrypted data which could not be read. 
       FIG. 2  shows a different implementation that lets the second user see the object  6  if he has licensed object  6 . 
     In order to avoid unauthorized exchange of this encrypted object  6  between users, the keys  7  and  7 ′ provided with the object  6  are different from a user to another. To achieve this, the keys  7  and  7 ′ can be specific to the encrypted object and are specific to the software license. 
     In order to allow the exchange of the view  8  between the two users, a generic key  21  is provided together with the data defining the encrypted object  6 . This generic key  21  is encrypted with the specific key  7  or  7 ′ of the user. This generic key  21  is unique for a given encrypted object but specific to each object. 
     This way, when the first user saves  9  the view  8  in the file  10 , he can decipher the generic key  21  with his key  7  specific to the object  6 . Then the first user can use the generic key  21  to encrypt the object  6  (that he has modified or not in the view). The data  10 . 3  resulting of this encryption is stored in the file  10 . 
     Then, when the second user receives  15  the file  10 , he can read data  10 . 4  that allows the unique identification of object  6 . He can then locate object  6  in the memory of his computer, and use his key  7 ′ specific to the object  6  in order to decipher the generic key  21 . And then he can use this generic key  21  to decipher the encrypted data  10 . 3 . The encrypted data  10 . 3  relates to the encrypted object  6  and to the possible modifications the first user has made to this object  6 . 
     Moreover, as in  FIG. 1 , the objects  3 - 5  are stored as public data  10 . 1  in the file  10 . This public data  10 . 1  is not encrypted. 
     Thus when the second user reads the file  10 , he can see all the 3D view created by the first user, including the car  6  (modified or not by the first user) for which he is licensed. 
     In the invention, the object encrypted in the file  10  can be identified among all the encrypted objects  6 ,  23  owned by the second user. To achieve this, the encrypted objects  6 ,  23  are identified by non-encrypted identifiers ID 1 -IDN. These identifiers ID 1 -IDN identify the encrypted objects in a unique way. The identifiers ID 1 -IDN can be the name of the encrypted object. 
     In a particular embodiment, the identifier ID 1  corresponding to the car is stored in the file  10 . Thus when the second user reads ID 1 , he can know whether or not he is licensed for the car  6 . In other words, when the second user reads ID 1 , he can know whether or not he has the key  7 ′ permitting the access to the generic key  21 . 
     A system which is external and independent from the piece of software is able to give a unique identifier to each encrypted object. This independent system can be for instance a web site which first finds a new ID that has not been used yet with the existing encrypted objects, and then gives this new ID to a new encrypted object. 
     Furthermore, when the second user receives the ID of the encrypted object, he can browse his hard drive in order to locate the object corresponding to the ID and get the generic key associated to this ID. 
     However, in a preferred embodiment, a table  30  represented at  FIG. 3  is created for each user. Thanks to this table it is possible to locate quickly the encrypted object in the memory of the user&#39;s computer. To achieve this, the table  30  contains the identifiers ID 1 -IDN of the encrypted objects owned by the user and the location L 1 -LN of these encrypted objects in the memory of the user&#39;s computer. 
     In this table  30 , the identifiers ID 1 -IDN are associated to the locations L 1 -LN of the encrypted objects in the memory of the user&#39;s computer. This way it is possible to know quickly that the encrypted car  6  and its generic key  21  associated to ID 1  are located in location L 1  of the user&#39;s hard drive, and a stone  23  and its generic key  25  (different from the generic key  21 ) associated to IDN are located in location LN of the user&#39;s hard drive. 
     Thus, when the second user receives ID 1  that identifies the car  6 , he can read table  30  and find location L 1  of the car in the memory of his computer. Then he can locate the generic key  21  associated to the car  6 . 
     The table  30  is updated each time the user acquires or uses a new encrypted object and stores it in the memory of his computer. The table may not be the same from one user to another, the user being free to choose the location of a new object in the memory of his computer. 
     In an alternative embodiment, after having read the identifier ID 1  of the file  10 , the second user does not decipher the encrypted data  10 . 3  with the generic key  21 . Instead, the second user replaces the encrypted object  6  of the view by the encrypted object  6  located in the library of his software. In this embodiment, the encrypted data  10 . 3  may be excluded from the file  10 . This embodiment may be useful if no modification has been made to the encrypted object  6  by the first user. 
     The piece of software according to the invention can be stored on a physical support which can be any support able to store data, for instance an optical disk (CD, DVD), or a USB device, or a card, or it can be sent to the end user via a communication network such as the Internet.