• Field Notes 24.11.2010

    The previous blog discussed the emergence of BIM and what data architects can include in the models that would have value to the glazing sub. This post will delineate some of the things I see coming regarding how glazing subs can use BIM models, and where this might take the industry down the road.

    Out of the box, most companies will try to use BIM with the simplest of their product lines, be they storefront or pressure wall systems. And after some trial and error, implement BIM to other product lines.

    But first, a couple of assumptions, if I may be so bold:

    1. I’m writing this as if I have my own glazing systems. As a manufacturer, TGP does. It’s recognized most of the glazing subcontractors do not. Instead, they typically buy their curtain wall and window wall products from manufacturers, such as TGP or the myriad of suppliers out there. Most, if not all, of the larger manufacturers are developing BIM models, largely for use of the architects for now. Most of the data suggestions I’m going to make below can either be imbedded in the models available from the manufacturers (through downloads or on CD), or would require some customization by the glazing subs for their individual situations.

    2. It’s highly unlikely that buying the software and opening a BIM model on your computer will make any organization ready to implement BIM across their entire processes, products, and organizations. Just as in the ’80s with the advent of CAD, there’s probably a lot of upfront software and geometry development that must precede or be part of an implementation plan. Some of what went on with the implementation of CAD was creating standard libraries and/or operating procedures, file naming, dimensional standards, etc. I don’t know this for a fact, but my guess is some of that will have to be done for BIM, as well.

    So what useful info to glaziers could be embedded or attached to a typical BIM model? I’m venturing a guess that a lot of what your company has already developed for its standard libraries can be converted to BIM models fairly easily. Take a typical horizontal or vertical detail cut, and attach data to it that includes:

    1. Working point/control point, be it at face of glass or face of cap and where it lays on the framing member centerline.

    2. Profile/part numbers of framing members, exterior caps or pressure plates, gaskets, or any other parts that run full length of the profile:

    • Some background info can be embedded to flag an alert for any part that runs longer than the longest finish or stock length allowed by the suppliers.
    • Finishing information can be attached to each part. Weights and exposed / finished surface perimeters can be added, as well.
    • Section properties can be added, especially if the part later is going to have to be analyzed for calculation purposes.

    3. Glass edge, in relation to the working point/control point mentioned above.  This will eventually establish glass sizes.

    4. Equally important will be to identify or create models of the glazing infills – be they glass, metal, granite, or other product – by thickness, manufacturer, unit construction (in the case of glass), minimum and maximum sizes, etc.

    For horizontals, information such as the shear blocks and their associated fasteners could be added, or just assembly fasteners say for a unitized wall system. The BIM model would know that for every horizontal, two shear blocks would be required, plus the quantity of fasteners needed to attach the horizontal to vertical.

    For mullions, things such as mullion splices could be added. Also, they would include the stop/start point of horizontals attached to them, so that the horizontal models would know where to start/stop in the model. By selecting that end point information or, better yet, the programming done within the software, the horizontals look for the information in the vertical model and thereby set their own length, “extruding” themselves to that point.

    3D anchors can be developed based on the system they are supporting, and/or the construction of the building frame. If the building structure were concrete, the embed type and size could be attached to the BIM model. For steel structures, the type of connecting fasteners or welding requirements could be added.

    Perimeter details can have information about sealant joint sizes and product data attached to them. Thermal insulation and/or fire-safing can be added to typical details, or as their own stand-alone models.

    For customization or fitting each job’s unique characteristics to the model, special conditions may have to be drawn from scratch, such as at a special coping, soffit, or corner conditions. Any of the attributes mentioned above – such as finish, length, relation to the control pointes, etc. – can be added to these one-off details.

    Once the base system frame system details are developed, they have to be attached to the architect’s BIM model. Using the 3D wireframe is the simplest. By selecting a grid line and associating a BIM-friendly detail to it, the total length of the part can be known based on that wireframe length. Corner mullions, horizontals, jamb details, etc. can all be attached to the model. The horizontal details are smart in that they know to stop at the side wall of the mullion, or can be told that based on the system, they should stop a fixed distance from vertical grid lines. Adding the anchor details at the frame-to-building structure will increase some accuracy of the downstream activities.

    If the glass information (or other glazing infill material) is embedded in the details, then the information from the verticals and horizontals has to close up and make individual lites of glass.

    Whew! So, lots of data can be added to BIM models that applies to glaziers. But, what can you do with all this information? That’s where the real party starts. Borrowing a line from Hollywood, tune in next time for the conclusion …

    Posted by Blogger @ 8:41 am

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