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JAN 04
2012

Exporting SDS/2 Models for BIM

With so many projects now requiring a BIM model for coordination and life cycle management, it's crucial to understand the capabilities of your software when it comes to collaboration and file sharing. What's most important to know is this: SDS/2 can create the file types you need to transfer your manufacturing model to software products like Autodesk® Revit® Structure and Navisworks.

This article will give you the information you need to conquer your next BIM project, including the most commonly used file types, such as DWG and CIS/2, and their benefits and drawbacks. You'll also learn about the latest file transfer option, the direct Revit import/export available in SDS/2 Connect.

What Is BIM, Anyway?
First, the basics: BIM is NOT any single software or file type; it is the model that contains and can communicate information through various file types.This information can be exported by selection from the model.

When working on a project with BIM requirements, your life will be infinitely easier if you know the model origin point before you start your model. While models can be relocated and reoriented through the model transfer process, it's easier to start with the correct point than change it later. Finally, communication that starts early and occurs often on the project will contribute just as much to the success of the project as will the right file type. Kick-off meetings are a great example of this.

U3D and VRML Files
The U3D and VRML file formats provide users with a great tool for visually representing a project. U3Ds are typically embedded in PDFs and are meant for communicating RFI information; VRMLs are generally used to generate 3D objects in the digital model. In SDS/2 v7.214 and higher, users have the ability to rotate the model, show insertion point, and include welds, holes or bolts when generating VRMLs.

However, it must be understood that these file formats are not designed for transmitting key information on a project.

"Many SDS/2 users typically provide VRML because it is free. However, VRMLs are meant to be just a simple visual representation of the model; they are not meant to carry intelligent information," according to Advisory Board member Brian Cobb.  "I've spent a lot of time discussing SDS/2 models at trade shows and GC (general contractor) forums, and any opposition I meet usually revolves around two things: uneducated users and VRML models being used incorrectly."

In other words, if you want to simply show what the model looks like, VRML and U3D are good options. For clash detection purposes with products like Navisworks, there are file types available that will provide better results.

Besides U3D and VRML files, SDS/2 also features additional exports that are a part of the optional ModelLINK package, including DXF, DWG, IFC and CIS/2.

DXF and DWG Files
In older versions of SDS/2, DXF files were the only Autodesk native file type that could be exported from SDS/2.  Typically, 3D DXF files become very large and can be cumbersome for import to collaborative models, when compared to the other available options. The DXF file had its uses, but technology has progressed, and this export is used less and less. 

A DWG, available in SDS/2 v7.220 and higher, is a more useful Autodesk native file type to send to Navisworks. For clash detection purposes in products like Navisworks, the DWG format provides simple, necessary information. In Revit Structure, DWGs can be used to bring in miscellaneous steel as its own layer for clash detection as well. Also, DWG files in SDS/2 v7.243 and higher have the ability to export color-coded members from status display settings.

Both the DWG and the DXF provide several export options, including rotation and translation. These options allow users to move the model if the point of origin is not in the correct location.

CIS/2 Files
The CIS/2 format contains very good information in relation to transferring engineering models from programs like RISA, RAM, and Intergraph’s SmartPlant 3D into SDS/2. SDS/2 also exports a robust CIS/2 file with options to define the type of model (analysis or manufacturing) and include attachments like CNC or drawings. It also provides options that make the CIS/2 file better suited to the software it is exporting to, such as unique settings that have been created for SmartPlant 3D.

While CIS/2 files are extremely data rich concerning structural steel, they lack the data for material types such as concrete. Additionally, it includes much more information than is necessary for clash detection. Due to the focus on steel design, CIS/2 files are more suited to communicating steel design information rather than clash detection information.

Until recently, AISC had endorsed the CIS/2 file format for structural steel. In October, the AISC released an article outlining the future for model transfers as they work with the buildingSMART Alliance to integrate the same level of steel information that exists in the CIS/2 format into the IFC file format. Click here to read the AISC article.

IFC Files
While IFC, along with DWG, is one of the most common of the file types used in BIM, understand that it is not BIM, nor is this file format required to be used in BIM. This is just one of the options. The IFC file format is useful for collaborative models because it is very wide, meaning that you can have a miscellaneous item like a door knob or a tree; however, it currently lacks the depth of information required for structural steel. IFC v2x4 is expected to improve upon that, and AISC will be putting efforts toward improving this in the future.

In general, an IFC allows you to communicate a large amount of information. SDS/2 has even fit some of its more detailed information into the IFC, in a way that couldn’t be done with CIS/2. For example, you can export status information with your IFC that can color code the Navisworks model to show the GC the state of approval or completion for your model. You can also store and export the GC’s steel related tasks and scheduling information in the SDS/2 model, which can be updated and exported via IFC.

SDS/2 Connect: Direct API File Transfer to Revit Structure
Design Data’s newest file exchange is completed through the $1,500 SDS/2 Connect add-in for Revit Structure. The import/export capabilities to interface with SDS/2 Connect are included for FREE in SDS/2 Detailing versions 7.241 and higher. Programmed with the Revit Structure API, SDS/2 Connect makes round-tripping between SDS/2 and Revit Structure possible. If you need to get your SDS/2 model into Revit Structure, SDS/2 Connect can allow you to do so, and bring system-designed connections with the model.

Rather than a universal file type, Design Data has worked directly with Revit Structure. The export capability actually takes your model and creates an XML file that then can be imported by the SDS/2 Connect add-in for Revit Structure. Through this add-in, SDS/2 users can send member-by-member updates to the engineer’s Revit Structure Model and vice versa. (Click here to view a video of this process.) Through SDS/2 Connect, engineers can also include some of your fabricator and job set-up options from SDS/2 to improve the design of the model and drive their models back downstream to SDS/2 detailers and fabricators.

SDS/2 Connect allows engineers to design connections inside Revit Structure if they wish, or they can simply import models from SDS/2 after the fabricator/detailer has designed the connections. This connection material will ONLY be sent between Revit Structure and SDS/2. This adds value to your model and can enhance accuracy and communication on BIM projects.

If you are planning to collaborate within Revit, or your deliverable is a Revit Structure model, it is possible that the SDS/2 Connect add-in can provide better information. For the price, SDS/2 Connect is a great way for engineers or GCs to get connection material into Revit Structure.

The New Norm is BIM
BIM-compliant models as a deliverable are becoming a necessity. More and more BIM projects are being bid every day, and you will find yourself with fewer opportunities for work if you cannot provide required BIM data. Arm yourself with the right tools to provide the best deliverable to your client. If that means they need a DWG and it’s not free, try to absorb the cost into your bid.

As detailers or fabricators, your best bet is to educate yourself on the types of files you can provide—be an expert and your business will reap the benefits. Follow us on Twitter and Facebook to receive tech tips and savings on ModelLINK transfers.