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By Protim Banerjee, August 20, 2012
GRAITEC is a major software developer in the AEC domain, with a global presence and a position strengthened by the spate of acquisitions it made over the last decade. The company offers software for structural analysis and design, structural steel modeling and detailing, and concrete modeling and detailing. Like other AEC software developers, GRAITEC in recent years also have been actively promoting its BIM (building information modeling) capabilities. GRAITEC’s BIM product suite is named GRAITEC Advance, and is the subject of this review.
To facilitate BIM, data is exchanged - imported and exported - between applications using GRAITEC’s own transfer file format (*.gtc files), as well as through industry standard formats, such as IFC and SDNF. (See figure 1.)
Figure 1: GRAITEC’s BIM workflow
To exchange model data to and from Revit Structure using GTC format, a free Revit add-on is available for download from the GRAITEC website, following email registration. The Revit add-on generates GTC files for import into GRAITEC applications. Two-way exchange works with the same Revit add-on, and a comprehensive set of supported items is listed by the GRAITEC Web site as a quick reference.
The Revit add-on allows model synchronization, a tool very useful for comparing the original model with updated ones. The changes that are alerted include member additions (appended), member modifications (modified), and member deletions (deleted); the alerts are made by color coding and by tabulating them in the synchronization dialog. You can review the changes, and then decide whether to accept them.
Links to Tekla and Staad Pro are available only from GRAITEC’s Advance Steel software. In this case, model data exchange is done with the CIS/2 and STD formats, respectively.
After reviewing the impressive amount of information presented by GRAITEC’s Web site, I downloaded the Revit add-on, which is approximately 100MB in size. I installed it on Revit Structure 2012, where the add-on appears as a Revit extension in the Add-Ins tab (External Tools).
I then set about exporting a number of Revit models into GTC format, and imported each one into GRAITEC applications. To test the add-on thoroughly, I carried out the following scenarios:
I randomly selected five Revit Structure models from my collection, as long as they had both structural steel and concrete elements. I was able to export three of the five models without problem. But the Revit add-on declined to export the other two, popping up an error message that said, “Sorry for the inconvenience.” It would be very useful if GRAITEC could detail the export problem so that we could take corrective actions, or work at a workaround.
Additionally, I created new Revit Structure 2012 models to review specific features.
The GTC file exported from Revit can be imported into Advance Design using the Import GRAITEC BIM option. (See figure 2.) Advance Design automatically maps the Revit cross sections (families) based on the country code used.
Figure 2: Model exchange with Advance Design 2012
A dialog appears when Advance Design cannot map cross sections automatically. In such cases, I needed to create new cross sections, or else select one from the cross section library included with Advance Design. (See figure 3.)
|Figure 3: Cross section mapping dialog in Advance Design 2012|
To aid cross section mapping, the cross section profile carried over from the Revit family is displayed in the top left hand corner of the dialog box. I found the cross section mapping very user-friendly. Any cross sections I mapped were remembered when I re-imported same GTC file to Advance Design.
The overall cross section mapping system is well designed, and so I expected this dialog box to appear for user-defined Revit Structure families only. A problem I found here was that the standard cross section families installed with Revit are not mapped automatically, such as the UKC sections shown in the figure above. In the current version of the GRAITEC add-on, you can expect to spend some time mapping cross sections, and then reacting to messages generated for different section sizes - even those belonging to same cross section type, such as UKC 152x152x51 and UKC 203x203x71.
When the model is transferred between applications, the position of its elements is based on the analytical line position in Revit Structure. I found that vertical eccentricities and member orientations were imported, but not lateral offsets. (See figures 4 and 5.)
Revit Structure 2012
Advance Design 2012
|Figure 4: The 3D representation of the model used to review member alignment and rotation|
|Figure 5: Member alignment after exporting the model from Revit Structure to Advance Design|
Another case I tried was one with asymmetric cross sections. Again, member orientation was not consistent with standard Revit cross section families. For example, figure 6 below shows the channel sections brought in properly, but the angle section is rotated by 180 degrees.
When I reported the issues affecting section mapping, offset, and rotation to GRAITEC, they informed me that they are fixed in the latest release, v3.0.28 (dated 25/07/2012), as is reported at their Web site www.graitec.com/en/revit_history.asp.
The report generated during the export does not highlight the above anomalies. Therefore, I found I had to carefully audit the structure to ensure cross sections alignments were set up properly.
GRAITEC Advance Design
|Figure 6: Member orientation problem in Advance Design|
Out of curiosity, I imported an Advance Design model into Revit Structure to check if the above anomalies occur in the reversed workflow. For this purpose, I created a new Advance Design model to review various cases, using the default member eccentricity options provided by Advance Design. Again there were inconsistencies in the imported Revit Structure 2012 model, as shown in figure 7 below.
|Figure 7: Member alignment– Exporting model from Advance Design 2012 to Revit Structure 2012|
Levels from Revit Structure are imported into Advance Design, and are populated in the GRAITEC project explorer tree, known as “Pilot.” This feature is handy for managing big projects.
As well, Revit’s loads and supports are imported into Advance Design. I feel a structural engineer would be more comfortable doing the modeling of loads and supports in Advance Design (rather than Revit Structure), hence I did not spent much time reviewing them.
For Advance Steel, I used the same set of GTC files that I used earlier for Advance Design. The import process was smooth, and the results were almost similar to that of Advance Design. Concrete cross sections were brought in as ACIS volumes, and the structural steel cross sections were mapped to the standard Advance Steel cross section library. The cross section mapping dialog is, however, different from that of Advance Design; it would be helpful if the Advance Design cross section library were used, as it is more versatile than the one included with Advance Steel. (See figure 8.)
Figure 8: Cross section mapping dialog in Advance Steel 2012
I came across a problem when I accidentally configured a wrong cross section, and then could not change the setting. Be careful when doing mappings!
As I expected, Advance Concrete imports only concrete elements. Structural steel cross sections are identified automatically and ignored. The problem, however, is that sometimes structural steel elements are not identified as such by Advance Concrete, and so I was forced to choose equivalent concrete sections. After I importing the model, I deleted these sections; an option to ignore these sections would be very useful - as found in Advance Design.
The cross section mapping dialog is different than those used in Advance Design and Advance Steel. (See figure 9.)
Figure 9: Cross section mapping dialog in Advance Concrete 2012
The elements of structural models are transferred as 3D solids and can be directly used for reinforcement detailing in Advance Concrete. The Revit Structure levels are identified and are populated in GRAITEC Pilot.
Any changes done to the model in Advance Design, Advance Steel, or Advance Concrete can be synchronized back to Revit Structure. I had the option to accept, ignore, or delay the changes. A filter is available to categorize changes according to the type of structural element, the change, or the status of the change. I could save reports on the updates as *.DOC files, which is a good tool for tracking revision history.
I think it would be useful if this synchronization were available as a superimposed graphical model (as with Revit’s copy monitor option). Otherwise, it becomes tedious to identify and locate changes in complex building structures.
The GTC file format is used also to transfers models between GRAITEC products: Advance Design, Advance Steel, and Advance Concrete. For example, after completing the structural analysis in Advance Design, I exported the model to Advance Steel for creating structural steel drawings, and then to Advance Concrete to create reinforcement detail drawings.
The concept works fine, and I found just one problem: I was prompted for cross section size mapping while importing the GTC file. I expected that model exchange between GRAITEC products would map cross sections automatically using a common GRAITEC library. GRAITEC informed me that there is an option to use the Advance Steel library, but that is not set by default due to certain legacy issues.
Once cross sections are mapped, the information is stored. As before, take care while doing the cross section mapping, because once a wrong cross section is mapped it cannot be removed from memory.
Advance Design has a feature called “dynamic reinforcement,” which is meant to be used as a post-processor (after analysis) to apply reinforcement cages and meshes to reinforced concrete elements, such as columns, beams, walls, and slabs. After performing my structural integrity checks, I tried to model this reinforcement in a simple slab structure and thought it would take the redesigned reinforcement quantities to Advance Concrete automatically. But it seems to me that the dynamic reinforcement feature is not fully implemented; I could not specify reinforcement in Advance Design. The GRAITEC support team confirmed to me that the dynamic reinforcement feature is still under development.
Fortunately, analysis results can be exported from Advance Design to Advance Steel. This function is useful, because member forces are automatically taken along for connection design in Advance Steel.
GRAITEC has carefully conceived the overall BIM process with the use of its GTC file format. The concept of cross section mapping and synchronization of changes is certainly very innovative. GRAITEC scores good points when it comes to the software design.
There are, however, still a few gaps in the implementation, as I highlighted with the cross section mappings, member alignment, member rotation, and transfer of member forces. A detailed report on member import and export information would be helpful in troubleshooting in those cases when the exchange fails.
The GRAITEC Advance Suite of products covers all aspect of structural BIM workflow. It does require some amount of training to make the best use of available functions. Users should find GRAITEC's suite of products useful for large projects with the fixes available in the latest release of their Revit add-on.
|Protim Banerjee has 15 years of experience in construction management, structural engineering and AEC software development. He is actively involved in developing desktop, enterprise and mobile software products in the AEC domain. He has a degree in civil engineering. More…|
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