What is Integrated Structural Modeling?
Bentley’s Integrated Structural Modeling (ISM) is a technology for sharing structural engineering project information among structural modeling, analysis, design, drafting and detailing applications. ISM is similar to Building Information Modeling (BIM), but focuses on the information that is important in the design, construction and modification of the load bearing components of buildings, bridges and other structures.
Purpose
There are two related purposes for ISM:
- The transfer of structural information between applications.
- The coordination of structural information between applications.
To provide for the first purpose (transferring information), ISM provides a means of defining, storing, reading and querying ISM Repositories.
To provide for the second purpose (coordination of information), ISM additionally provides capabilities to detect differences between ISM Repositories and to selectively (based on user selection) update either an ISM Repository or an application’s data to provide a user-controlled level of consistency between the two data sets.
How ISM Works
The process of Integrated Structural Modeling is facilitated through a few important technology pieces. At the core is a free component called iTwin Analytical Synchronizer. iTwin Analytical Synchronizer resides on each user’s desktop and provides the following key capabilities in one application:
- API for applications to access
- Change Management
- Visualization
- Data interrogation
- Storing and retrieving consensus data in/from a file
ISM and Application Data
ISM is not intended to store all of the information that all of its client applications contain. Rather, it is intended to store and communicate a consensus view of data that is common to two or more of its client applications.
ISM client applications continue to hold and maintain their own private copy of the data. Some of the application data will duplicate that of the associated ISM Repository. The application data may even conflict with that in the ISM Repository. The client application (or you as its user) may decide that a conflict gives the best data for the application’s and ISM’s different uses.
An example of an intentional data conflict would be a user giving a concrete beam in an analysis application a special concrete mix with a lower elastic modulus to simulate the reduced stiffness due to cracking. This concrete mix assignment would not be appropriate for the ISM Repository since the special concrete mix was intended solely for this application’s analysis purposes.
Integration between Applications and ISM
Each Application that links to ISM must develop and deploy a Product-ISM Link. This key component may be embedded in the application executable or provided as an independent plugin. Typically these links are delivered together with the specific product.
Each Link enables exporting application models to ISM models and importing an ISM model to the application. This means that transfering data from one application to another is possible. For example, through ISM a RAM Structural System model can be converted to Revit.
There are several product-ISM links already available on the market and not just for Bentley products. Links to Revit, Tekla and Dlubal are currently available. From Bentley RAM Elements, RAM Concept, RAM Connection, RAM Structural System, SACS, STAAD.Pro, RCDC, AutoPIPE, AutoPIPE Vessel, MOSES, OpenBuildings Design and ProStructures are all ISM enabled.
Integrated Structural Modeling Features
Visualization
Shipped with ISM is a state-of-the-art structural viewer to share and distribute to all project participants. The ISM Viewer allows you substantial control for visualization and data interrogation of ISM database. Here is a short list of capabilities included in the viewer:
- Walk and Fly-Through
- Intelligent data interrogation of objects
- Query interface to find objects
- Multiple layer control to turn off and on large groups of data
- 3D Viewing controls/PDF print capabilities
Change Management
A powerful change management tool is provided to manage the changes to data that is coming into and going out of ISM through the project lifespan. This change management tool allows the user to easily identify elements that have been added, deleted or modified since the previous update to or from ISM. Presented with these differences the user has full control to accept or reject those elements which they want to have updated in ISM or in the application they are currently looking to update from ISM. Presented in this screenshot is the standard view of change management:
The change management window is comprised of several different parts but most significantly the added, modified and deleted objects are displayed and color coded in the Objects table:
The items listed in the Objects table are controlled by the filters toolbar:
These buttons control what objects are displayed in the Objects table. It allows the user to filter based on type of member (node, surface member etc.), the state of the object (whether newly added, deleted or modified) or the user decision for that object i.e. whether you have accepted or rejected the changes. Similar property table options are available to filter properties of objects that may have changed between two models.
The visual impact of the changes can also be previewed by setting the state of the object (accept or reject changes) and clicking the preview button. Many other controls similar to those in the viewer are also available to allow data interrogation and to isolate and easily find specific members or groups of members. Data in any project is always changing and ISM was specifically built to handle the dynamic nature of the data rather than working with a static snapshot at a particular point in the project timeline.
Revision History
Integrated Structural Modeling provides the opportunity to tag each update to the ISM model with Major/Minor setting, date stamp, user credentials and description. At any time within the project lifespan each specific change can be identified and interrogated to show exactly what was added, deleted or modified in that session. A rollback capability is also included with ISM to allow the user to return the ISM model to any of the previous states.