CN112784341A

CN112784341A - BIM (building information modeling) model attribute determination method and device, computer equipment and storage medium

Info

Publication number: CN112784341A
Application number: CN202110125535.1A
Authority: CN
Inventors: 李凡坤
Original assignee: Glodon Co Ltd
Current assignee: Glodon Co Ltd
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2021-05-11
Anticipated expiration: 2041-01-29
Also published as: CN112784341B

Abstract

The invention provides a BIM (building information modeling) model attribute determination method, a BIM model attribute determination device, computer equipment and a storage device, wherein the method comprises the following steps: acquiring a first BIM model; analyzing the first BIM model to obtain data information in the first BIM model, wherein the data information comprises three-dimensional shape information and first attribute information, the three-dimensional shape information is used for representing the geometric shape of the first BIM model, and the first attribute information is attribute information defined when the BIM model is created; determining a target class of the first BIM model based on the three-dimensional shape information; acquiring second attribute information corresponding to the target category; the second attribute information is standardized attribute information corresponding to the target category; determining target attribute information of the first BIM model based on the first attribute information and the second attribute information.

Description

BIM (building information modeling) model attribute determination method and device, computer equipment and storage medium

Technical Field

The invention relates to the technical field of BIM models, in particular to a BIM model attribute determination method, a BIM model attribute determination device, computer equipment and a storage medium.

Background

BIM models play an increasingly important role in building engineering. For the BIM model, the attribute information may describe features of the model from different dimensions, such as size, material, color, etc., and thus the attribute information is an important component of the BIM model. Currently, for each building engineering project, a designer usually draws a new BIM model for each building component, which is very labor-consuming and material-consuming. Even BIM models of the same component often have different attribute information based on different drawing habits or different application scenarios. Under the condition, the BIM model is difficult to smoothly circulate in the building project, and the model value is difficult to effectively exert.

Therefore, how to perform normalized management on the attribute information of the BIM model to improve the universality of the BIM model becomes a problem to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide a technical scheme capable of managing attribute information of a BIM in a standardized manner so as to solve the problems in the prior art.

In order to achieve the above object, the present invention provides a method for determining attributes of a BIM model, comprising the following steps:

acquiring a first BIM model;

analyzing the first BIM model to obtain data information in the first BIM model, wherein the data information comprises three-dimensional shape information and first attribute information, the three-dimensional shape information is used for representing the geometric shape of the first BIM model, and the first attribute information is attribute information defined when the BIM model is created;

determining a target class of the first BIM model based on the three-dimensional shape information;

acquiring second attribute information corresponding to the target category; the second attribute information is standardized attribute information corresponding to the target category;

determining target attribute information of the first BIM model based on the first attribute information and the second attribute information.

According to the attribute determining method of the BIM model provided by the present invention, the step of determining the object class of the first BIM model based on the three-dimensional shape information includes:

comparing the first BIM model with a plurality of candidate BIM models for similarity; wherein the candidate BIM models have been pre-labeled with corresponding categories;

and taking the category of the candidate BIM model with the highest similarity as the target category of the first BIM model.

According to the attribute determining method of the BIM model provided by the present invention, the step of comparing the similarity of the first BIM model with the plurality of candidate BIM models includes:

selecting a plurality of different viewing angles, and respectively acquiring first image characteristics of the first BIM model under each viewing angle;

respectively acquiring second image characteristics of the candidate BIM model under each view angle;

and calculating single similarity between the first image feature and the second image feature at each view angle, and weighting and summing the single similarities at all the view angles to obtain comprehensive similarity.

According to the attribute determining method of the BIM model provided by the present invention, the step of determining the target attribute information of the BIM model based on the first attribute information, the second attribute information and the constraint relationship information includes:

comparing all the attribute names contained in the first attribute information with all the attribute names contained in the second attribute information to obtain the same attribute name and different attribute names;

determining an attribute name to be reserved from two same attribute names according to a preset priority rule;

taking the attribute name to be reserved and the different attribute names as target attribute names in the target attribute information;

and acquiring a target numerical value corresponding to the target attribute name.

According to the attribute determining method of the BIM model provided by the invention, the step of determining an attribute name to be reserved from two same attribute names according to a preset priority rule comprises the following steps:

judging whether a geometric driving relation exists between the same attribute name and the first BIM model;

if so, taking the same attribute name in the first attribute information as the attribute name to be reserved;

and if not, taking the same attribute name in the second attribute information as the attribute name to be reserved.

According to the attribute determination method of the BIM, the data information further comprises constraint information, and the constraint information is used for representing a constraint relation which needs to be met by the first BIM;

after the step of obtaining the target value corresponding to the target attribute name, the method further includes:

checking the target value based on the constraint information to determine whether the target value is within a reasonable range;

and sending out prompt information under the condition that the target numerical value is not in a reasonable range.

According to the attribute determination method of the BIM model provided by the present invention, the step of checking the target value based on the constraint information to determine whether the target value is within a reasonable range includes any one or more of the following steps:

checking whether the target value meets the geometric constraint relation between the first BIM model and other BIM models;

checking whether the target numerical value meets a preset formula constraint relation;

and checking whether the target value meets a preset driven parameter constraint relation.

In order to achieve the above object, the present invention further provides an attribute determining apparatus for a BIM model, including:

a model acquisition module adapted to acquire a first BIM model;

the analysis module is suitable for analyzing the first BIM model to obtain data information in the first BIM model, wherein the data information comprises three-dimensional shape information and first attribute information, the three-dimensional shape information is used for representing the geometric shape of the first BIM model, and the first attribute information is attribute information defined when the BIM model is created;

a category determination module adapted to determine a target category of the first BIM model based on the three-dimensional shape information;

the standard attribute module is suitable for acquiring second attribute information corresponding to the target category; the second attribute information is standardized attribute information corresponding to the target category;

an attribute determination module adapted to determine target attribute information of the first BIM model based on the first attribute information and the second attribute information.

To achieve the above object, the present invention further provides a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the above method when executing the computer program.

To achieve the above object, the present invention also provides a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the above method.

The BIM attribute determination method, the BIM attribute determination device, the computer equipment and the readable storage medium can realize online standardized editing of the attribute information of the BIM. On one hand, the invention obtains the custom attributes added by the user when the BIM is created, on the other hand, the invention obtains the corresponding standardized attributes according to the classification of the BIM, and finally determines all attribute information contained in the BIM by integrating the custom attributes and the standardized attributes. Furthermore, the attribute information editing process can be directly carried out in the cloud through a browser, and client software does not need to be installed, so that light-weight editing can be realized. The invention is beneficial to improving the standardization degree of the BIM model, saving the workload of manually editing the model and accelerating the circulation efficiency of the BIM model in different stages of the engineering.

Drawings

FIG. 1 is a flowchart of a first embodiment of a BIM attribute determination method according to the present invention;

FIG. 2 is a schematic flow chart of calculating similarity according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart diagram illustrating the determination of target attribute information in accordance with one embodiment of the present invention;

FIG. 4 is a schematic diagram of a program module of a first embodiment of an apparatus for determining attributes of a BIM model according to the present invention;

fig. 5 is a schematic diagram of a hardware structure of a first embodiment of the attribute determining apparatus according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

Referring to fig. 1, the present embodiment provides a method for determining an attribute of a BIM model, including the following steps:

and S100, acquiring a first BIM model.

The embodiment is suitable for a remote server, and the server is used for receiving, storing and managing various BIM models uploaded by different users in engineering projects. Wherein, the user can upload the BIM model through the page on the browser. It will be appreciated that for ease of transmission, the first BIM model received at the server side is typically in a compressed file format.

S200, analyzing the first BIM model to obtain data information in the first BIM model, wherein the data information comprises three-dimensional shape information and first attribute information, the three-dimensional shape information is used for representing the geometric shape of the first BIM model, and the first attribute information is self-defined attribute information of a user when the BIM model is created.

In this step, the server analyzes the received first BIM model based on a preset format to obtain corresponding three-dimensional shape information and first attribute information. The three-dimensional shape information is a digital representation of the three-dimensional shape of the model, and the specific spatial composition of the first BIM model, for example, the three-dimensional shape formed by the superposition of patches, can be determined by the three-dimensional shape information. The first attribute information is a series of features included in the first BIM model that define the BIM model from multiple dimensions, such as geometric attributes that define the model from a geometric parameter perspective, material attributes that define the model from a composition material perspective, color attributes that define the model from a color perspective, and the like. It can be understood that different BIM models may include different attribute information, and the same BIM model may also include different attribute information in different application scenarios, which is not limited in this embodiment.

And S300, determining the target class of the first BIM model based on the three-dimensional shape information.

The category in the present embodiment refers to the minimum range unit to which the component corresponding to the BIM model belongs. For example, the building elements can be classified into heating and ventilating elements, building elements, electrical appliance elements, etc. according to their specialties, the building elements can be further classified into shear walls, beams, columns, etc., and if further classified, the columns can be further classified into side end columns, hidden columns, etc. In short, the components can be divided into multiple classes according to national standards or other preset rules, and each BIM model can determine the class according to the corresponding component. In one example, a category may include a name of a component.

The object class of the first BIM model may be determined in a number of ways. For example, the first BIM model is compared with candidate models of determined classes in a preset model library, and the class to which the candidate model with the highest similarity belongs is used as the target class of the first BIM model. For example, the trained machine learning classification model is used, and the first BIM model is used as input data, so that output class data is obtained. Specifically, the training process of the machine learning classification model may include: acquiring a large amount of sample data, wherein the sample data comprises training BIM models and corresponding classifications of each BIM model; constructing a function expression between a training BIM model and the classification; and taking the training BIM model as input, and taking the corresponding classification as output training classification model, thereby determining the weight coefficient in the function expression. The machine learning classification model may be based on an artificial neural network model or any other machine learning model, which is not limited in this embodiment.

S400, acquiring second attribute information corresponding to the target category; the second attribute information is normalized attribute information corresponding to the target category.

Based on each determined category, the present embodiment sets in advance a series of standard attribute information (i.e., second attribute information) corresponding to the category for defining the features that the member under the category needs to provide. For example, for a member whose category is "door handle", the corresponding standard attribute information includes a size attribute, a material attribute, a color attribute, an attachment direction attribute, and the like. Each standard attribute information in the embodiment corresponds to a normalized code, and the normalized code is favorable for reducing data storage pressure and improving data retrieval speed. Those skilled in the art understand that the second attribute information may be the same as the first attribute information or may be different from the first attribute information.

And S500, determining target attribute information of the first BIM model based on the first attribute information and the second attribute information.

The target attribute information refers to all attribute information stored in the server by the first BIM model. Different rules may be formulated to determine target attribute information for different application scenarios. For example, the target attribute information is determined according to a part of the first attribute information and a part of the second attribute information, wherein the respective proportions of the first attribute information and the second attribute information in the target attribute information can be formulated according to a specific application scenario. It can be seen that, in this embodiment, the process of determining the target attribute information is directly performed at the remote server, that is, the user can perform light-weight online attribute editing on the BIM model stored at the remote server through the browser without installing client software, so as to improve the editing efficiency.

Through the steps, the embodiment can quickly determine and store the target attribute information of the BIM. The target attribute information comprehensively considers the first attribute information customized by a user and the second attribute information formulated by an industry specification so as to ensure that the target attribute information of the first BIM model can have both individual characteristics and common characteristics, and realize the integrity and standardization unification of the BIM model in the aspect of attribute information.

As described above, in the process of determining the target category of the first BIM model in step S300, the first BIM model may be compared with the candidate models of the determined categories in the preset model library, and the category to which the candidate model with the highest similarity belongs may be used as the target category of the first BIM model. Fig. 2 is a schematic flowchart of calculating the similarity between the first BIM model and the candidate BIM model according to the first embodiment of the present invention. As shown in fig. 2, the step of calculating the similarity includes:

s310, selecting a plurality of different visual angles, and respectively acquiring first image characteristics of the first BIM model under each visual angle.

The plurality of different viewing angles in this embodiment may be set according to specific needs, for example, a front view viewing angle, a viewing angle in which the front view is shifted by 10 ° to the right, a viewing angle in which the front view is shifted by 30 ° to the left, a top view viewing angle, and the like, which is not limited in this embodiment. The first image feature may be a two-dimensional image directly obtained at each viewing angle, or may be a texture feature, a color feature, a shape feature, or other features extracted from the two-dimensional image, which is not limited in this embodiment.

And S320, respectively acquiring second image characteristics of the candidate BIM model under each view angle.

It should be noted that the viewing angle of the second image feature needs to correspond to the viewing angle of the first image feature. For example, the first BIM model obtains three first image features at the first view angle, the second view angle and the third view angle, respectively, and then the candidate BIM model also needs to obtain corresponding second image features at the first view angle, the second view angle and the third view angle, respectively. It can be understood that the accuracy of the comparison result can be ensured only by performing the comparison under the same viewing angle.

S330, calculating single similarity between the first image characteristic and the second image characteristic under each visual angle, and weighting and summing the single similarities under all the visual angles to obtain comprehensive similarity.

For example, if the similarity between the first image feature and the second image feature at the first viewing angle is S1, the similarity between the first image feature and the second image feature at the second viewing angle is S2, and the similarity between the first image feature and the second image feature at the third viewing angle is S3, then the integrated similarity S between the first BIM model and the candidate BIM model may be expressed as:

S＝a1s1+a2s2+a3s3

in the above formula, a1, a2, and a3 represent weight values of different viewing angles, respectively.

Fig. 3 shows a schematic flowchart for determining target attribute information in the first embodiment of the present invention. As shown in fig. 3, step S400 includes:

s410, comparing all the attribute names contained in the first attribute information with all the attribute names contained in the second attribute information to obtain the same attribute name and different attribute names.

The attribute information in this embodiment may include a plurality of attribute names. For example, the first attribute information includes an attribute name 1, an attribute name 2, and an attribute name 3, and the second attribute information includes an attribute name 2, an attribute name 3, and an attribute name 4. By comparing the attribute names, the same attribute name contained in both the first attribute information and the second attribute information and a different attribute name contained in only the first attribute information or the second attribute information can be obtained. In this example, it can be seen that the same attribute name includes attribute name 2 and attribute name 3, and the different attribute names include attribute name 1 and attribute name 4.

And S420, determining an attribute name to be reserved from two same attribute names according to a preset priority rule.

It can be understood that the attribute information of the same BIM model cannot contain two identical attribute names. Thus for two identical attribute names, it is necessary to determine which name needs to be retained and which attribute name needs to be deleted. Different priority rules can be made according to different needs to determine the same attribute name which is preferentially reserved.

In one example, the priority rule may be formulated by determining whether a geometry-driven relationship exists between the same attribute name and the first BIM model. The geometric driving relationship refers to that when the value of a certain attribute name is changed, the change of the geometric shape of the first BIM model is caused. It should be noted that the geometric driving relationship is usually customized by a user, and all the attribute names included in the second attribute information in this embodiment do not set the geometric driving relationship. Wherein the geometric driving relationship is included in the corresponding attribute name of the first attribute information. If the geometric driving relationship exists, taking the same attribute name in the first attribute information as an attribute name to be reserved; and if the geometric driving relation does not exist, taking the same attribute name in the second attribute information as the attribute name to be reserved.

S430, taking the attribute name to be reserved and the different attribute names as target attribute names in the target attribute information.

That is, this step will determine the same attribute name and all different attribute names that remain as the target attribute name for the first BIM model.

And S440, acquiring a target numerical value corresponding to the target attribute name. The target value may be obtained directly from the first attribute information, or obtained based on default data, or obtained based on user input, and this step is not limited.

Further, in this embodiment, the data information obtained after the analysis of the first BIM model may further include constraint information. The constraint information defines a constraint relationship between the related attribute value and the object in the first BIM model, and specifically includes a constraint relationship between the attribute value and other BIM components, a constraint relationship between the attribute value and a preset formula, or a constraint relationship between the attribute value and a preset driven parameter. On this basis, the step of determining the target attribute information in the present embodiment further includes:

s450, checking the target value based on the constraint information to determine whether the target value is within a reasonable range. The method specifically comprises any one or more of the following steps:

and checking whether the target value meets the geometric constraint relation between the first BIM model and other BIM models. For example, the member corresponding to the first BIM model is a door, and the members corresponding to the other BIM models are door frames. It will be appreciated that the target value may be considered to satisfy the above-described geometric constraint relationship only if the specific dimensional value of the door is within the dimensional range of the doorframe; otherwise, if the specific size value of the door exceeds the size range of the door frame, the target value is not considered to meet the geometric constraint relation.

And checking whether the target value meets a preset formula constraint relation. Still taking the component door as an example, assuming that a formula constraint relationship is H (height) >2W (width), the height of the door needs to satisfy a certain value range under the condition of fixed width, otherwise, the formula constraint relationship is not satisfied.

And checking whether the target value meets a preset driven parameter constraint relation. For example, when the first BIM model is a wall opening, the height of the wall opening is necessarily limited by the height of the shear wall, i.e., the height of the wall opening is smaller than the height of the shear wall. At this time, the target value is the height of the wall opening, and the driven parameter is the height of the shear wall.

By checking the constraint relation, the accuracy and the reasonability of the target value can be ensured

And S460, sending out prompt information under the condition that the target numerical value is not in a reasonable range. Therefore, the method is beneficial to the user to find out problems in time and carry out corresponding modification, thereby improving the accuracy of BIM model editing.

Continuing to refer to fig. 4, an attribute determining apparatus of the BIM model is shown, in the embodiment, the attribute determining apparatus 40 may include or be divided into one or more program modules, and the one or more program modules are stored in a storage medium and executed by one or more processors to implement the present invention and implement the attribute determining method. The program module referred to in the present invention means a series of computer program instruction segments capable of performing a specific function, and is more suitable than the program itself for describing the execution process of the attribute determining apparatus 40 in the storage medium. The following description will specifically describe the functions of the program modules of the present embodiment:

a model obtaining module 41 adapted to obtain a first BIM model;

the analysis module 42 is adapted to analyze the first BIM model to obtain data information in the first BIM model, where the data information includes three-dimensional shape information and first attribute information, the three-dimensional shape information is used to represent a geometric shape of the first BIM model, and the first attribute information is attribute information defined when the BIM model is created;

a class determination module 43 adapted to determine a target class of the first BIM model based on the three-dimensional shape information;

a standard attribute module 44, adapted to obtain second attribute information corresponding to the target category; the second attribute information is standardized attribute information corresponding to the target category;

an attribute determination module 45 adapted to determine target attribute information of the first BIM model based on the first attribute information and the second attribute information.

The embodiment also provides a computer device, such as a smart phone, a tablet computer, a notebook computer, a desktop computer, a rack server, a blade server, a tower server or a rack server (including an independent server or a server cluster composed of a plurality of servers) capable of executing programs, and the like. The computer device 50 of the present embodiment includes at least, but is not limited to: a memory 51, a processor 52, which may be communicatively coupled to each other via a system bus, as shown in FIG. 5. It is noted that fig. 5 only shows a computer device 50 with components 51-52, but it is to be understood that not all shown components are required to be implemented, and that more or fewer components may be implemented instead.

In this embodiment, the memory 51 (i.e., a readable storage medium) includes a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory, etc.), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, and the like. In some embodiments, the storage 51 may be an internal storage unit of the computer device 50, such as a hard disk or a memory of the computer device 50. In other embodiments, the memory 51 may be an external storage device of the computer device 50, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), or the like, provided on the computer device 50. Of course, the memory 51 may also include both internal and external storage devices for the computer device 50. In this embodiment, the memory 51 is generally used for storing an operating system and various application software installed in the computer device 50, such as the program code of the attribute determining apparatus 40 in the first embodiment. Further, the memory 51 may also be used to temporarily store various types of data that have been output or are to be output.

Processor 52 may be a Central Processing Unit (CPU), controller, microcontroller, microprocessor, or other data Processing chip in some embodiments. The processor 52 generally serves to control the overall operation of the computer device 50. In this embodiment, the processor 52 is configured to execute the program code stored in the memory 51 or process data, for example, execute the attribute determining apparatus 40, so as to implement the attribute determining method according to the first embodiment.

The present embodiment also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory, etc.), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, an App application mall, etc., on which a computer program is stored, which when executed by a processor implements corresponding functions. The computer-readable storage medium of this embodiment is used for storing the attribute determining apparatus 40, and when executed by a processor, implements the attribute determining method of the first embodiment.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A BIM model attribute determination method is characterized by comprising the following steps:

acquiring a first BIM model;

2. The method of claim 1, wherein the determining the object class of the first BIM model based on the three-dimensional shape information comprises:

3. The method of claim 2, wherein the step of comparing the similarity of the first BIM model with the plurality of candidate BIM models comprises:

4. The method according to claim 1, wherein the step of determining the target attribute information of the BIM model based on the first attribute information, the second attribute information, and the constraint relationship information comprises:

5. The BIM model attribute determining method of claim 4, wherein the step of determining an attribute name to be retained from two identical attribute names according to a preset priority rule comprises:

6. The attribute determining method of the BIM according to claim 4, wherein the data information further includes constraint information, and the constraint information is used for representing a constraint relation that the first BIM needs to satisfy;

7. The BIM model attribute determining method of claim 6, wherein the step of checking the target value based on the constraint information to determine whether the target value is within a reasonable range comprises any one or more of:

8. An attribute determining apparatus of a BIM model, comprising:

the model acquisition module is suitable for acquiring a first BIM uploaded by a user;

9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method of any of claims 1 to 7 are implemented by the processor when executing the computer program.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 7.