Every architect, contractor, engineer, and service provider in a construction project will refer to BIM shop drawings at some stage of the project. These drawings are a detailed blueprint and pictorial representation of the details and specifications in the architect’s and engineer’s designs for the building. They reflect the location and design for prefabricated components, including elevators, structural steel, air vents, and millwork, as well as mechanical, electrical, and plumbing (MEP) systems and plans. BIM shop drawings typically are more detailed than architectural renderings, as they include details that different subcontractors and building trades will refer to during the construction and installation of their systems.
Architectural, engineering, and construction (AEC) companies that had previously prepared BIM shop drawings internally are increasingly outsourcing this function to BIM shop drawing specialists. Those specialists prepare drawings in a shorter period of time and use specialized software and technology that would be too expensive for AEC firms to use and maintain internally. Outsourced BIM shop drawings are also standardized across several projects. Drawing standardization eliminates misinterpretations and simplifies MEP installation and other services by subcontractors that will no longer need to interpret different types of BIM shop drawings from project to project.
BIM shop drawings are most commonly prepared after the final review and approval of a building project. Preparation of a complete set of BIM shop drawings via in-house AEC company draftsmen can delay the start of the project by several weeks. The outsourcing service provider will shorten that time and retain accurate and complete records that simultaneously provide a complete data and audit trail with indexes that simplify drawing references for all parties that need to refer to the drawings. The service provider will also maintain a drawing log and a record of all approvals and will act as a central contact point for collaboration among service providers and as a source of answers for frequently-asked questions.
Outsourcing BIM shop drawings will require AEC firms to consider at least seven different aspects of a project.
- Comparison Information
As noted, BIM shop drawings include more detail than basic architectural drawings. That detail should include information to allow architects and engineers to compare a subcontractor’s and fabricator’s specifications for the project to the architect’s and engineer’s version in the overall building specifications. Material and system specifications from a manufacturer, and references to different phases in the construction of the project are particularly important for proper comparisons and verifications.
- Change Order Notations
No building project is completed without a number of change orders and revisions to different systems and specifications. BIM shop drawings will evolve with each change order. The BIM shop drawing outsourcing firm should generate a new set of drawings with each change order, and each new drawing set should include notations with references to specific change orders.
Fabricators of specific building components, including metal grillwork, millwork, and claddings, will use BIM shop drawings as references for dimensions, manufacturing standards, and special instructions. AEC firms should include as much fabrication detail on BIM shop drawings as is possible to reduce or eliminate miscommunications and errors.
- Job Site Dimensions
Even the best construction drawings will include variances between drawing and actual job site dimensions. BIM shop drawings should include specific notations for all potential variances to reduce the need to modify prefabricated systems and components at a job site. Job site dimensional variance notations on a BIM shop drawing will alert a subcontractor or fabricator to verify dimensions at the actual job site before starting any offsite fabrication.
- Placement and Installation
No components or systems are installed in a vacuum. Systems need to be connected to or combined with other structures. The BIM shop drawings should give subcontractors enough information, including (as necessary) lists of materials, proximity to other systems and clearances, and temporary access points to facilitate the most efficient installation of any individual system.
AEC firms frequently distribute samples of finishes or products that they have specified for installation in a new project. Samples can still be distributed with BIM shop drawings, and a BIM shop drawing outsourcing firm can scan and deliver 3D images of those samples for easy reference.
Conflicts between installations of major building systems are not uncommon in large building projects. BIM shop drawing specialists can prepare drawings that reveal, for example, the various stages of an HVAC system installation, and how that installation might impinge plumbing or electrical systems. BIM shop drawing specialists use advanced software, including Autodesk’s Revit family of applications, to coordinate MEP installation efforts and to predict and minimize conflicts between MEP subcontractors.
Once these aspects are taken into consideration, an AEC firm can turn to the specific types of BIM shop drawings that will best suit the needs of the construction project. All subcontractors and fabricators will benefit from 3D axonometric BIM shop drawings that show the entire construction project and how the individual subcontractor’s components or systems fit into the project. These drawings can clarify features such as complex or unusual rooflines and exterior walls and corners that may be at odd angles. Architects had previously built small 3D models to show these features. 3D BIM shop drawings accomplish the same purpose and more by integrating an overall rendering of the project with a subcontractor’s contribution.
BIM shop drawings can also include orthographic projections that show the front, side, back, and top-down views of the project. These perspectives help subcontractors to understand how the project occupies a building site as well as the footprint of the project on that site.
Cross-sectional BIM shop drawings will be useful to reveal the interior interactions of various systems in a building project. Individual systems can be segregated out of these sectional views into separate exploded assembly views that highlight specific component parts of larger systems on separate BIM shop drawings. The level of detail on these drawings will be determined by the needs and requests of the subcontractors.
The advantage of outsourcing the BIM shop drawing function to a specialist firm become most apparent when the need for these different types of drawings is considered. BIM shop drawing specialists, for example, can use advanced software technology to prepare separate sets of drawings that include system dimensions and installation tolerances at the actual building site. Few AEC firms have the expertise or manpower to maintain this ability and technology internally. Even if they do have the expertise, any drawing system that is specific to one AEC firm forfeits the benefit of standardization and consistency that subcontractors prefer.
INDBIM company specializes in providing quality CAD services and BIM shop drawings for AEC firms and all types of buildings, from small standalone structures to large commercial and industrial construction projects. Our services help AEC firms to reduce initial costs and eliminate unexpected cost overruns during project administration. Outsourcing a project’s BIM shop drawings and other drawing needs will allow AEC personnel to focus on the actual construction and operation of a building apart from the distractions that often arise from attempting to manage an in-house team or draftsmen. We provide the quickest turnaround time in the industry and offer the BIM shop drawing technology and expertise that you need to take your next building project from concept to reality.