BIM Collaboration

General Modeling Guidelines

This content is published to provide advance information to parties collaborating with HOK. It addresses some common scenarios that affect the productivity of collaboration using building information modeling. HOK’s approach to BIM has been evolving since 2004. This approach considers the modeled information to be the primary source of truth; therefore, it is expected that content contributed by consultants follow this same logic:

Two-dimensional documentation is to be extracted from the 3D model – the 3D model is NOT to be generated as a parallel effort to 2D drawings.

In general, all content that is depicted on document deliverables according to the acceptable standard of care is to be modeled in an approved BIM program (agreed BIM platforms will be documented in a Project Execution Plan or PxP). For design development and construction documents, modeled elements are to be created to a design level of detail - either generic [LOD200] or specific [LOD300], depending on the requirements of the project.

For project scope that includes new buildings or major alterations, HOK will develop a customized Project Execution Plan (PxP). The HOK PxP template is fundamentally similar to the BIM Project Execution Guidelines developed by Penn State University (, but is more modular to address a wide variety of project sizes and types.


Consultants are expected to share BIM data with HOK and other members of the design team. Models must be uploaded to a project collaboration system on an agreed schedule, set forth in the PxP.

The preferred BIM software application is Revit (Architecture, Structure, or MEP); however, other applications are acceptable such as AutoCAD MEP or Tekla Structures - provided that the document deliverables are still extracted from the 3D model.

Agreement on software applications including versions to be used on the project and data exchange procedures will be documented in the PxP.

Model Element Table

The Model Element Table (MET) is a more detailed specification of the modeling responsibilities throughout a project team. In other words, who will model what, and when. This will become a critical roadmap by which to measure each team member’s compliance with the modeling plan.

Levels of Development:

The Level of Development Definitions are produced by the AIA and have been used here by permission. Copyright © 2011. The American Institute of Architects. All rights reserved.

LOD100 “Estimate it.” The Model Element may be graphically represented in the Model with a symbol or other generic representation, but does not satisfy the requirements for LOD 200. Information related to the Model Element (i.e. cost per square foot, tonnage of HVAC, etc.) can be derived from other Model Elements.

LOD200 “Specify it.” The Model Element is graphically represented within the Model as a generic system, object, or assembly with approximate quantities, size, shape, location, and orientation.

LOD300 “Bid it.” The Model Element is graphically represented within the Model as a specific system, object or assembly accurate in terms of quantity, size, shape, location, and orientation.

LOD350 “Buy it.” The Model Element is graphically represented within the Model as a specific system, object or assembly in terms of quantity, size, shape, orientation and interfaces with other building systems.

LOD400 “Build it.” The Model Element is graphically represented within the Model as a specific system, object or assembly that is accurate in terms of size, shape, location, quantity, and orientation with detailing, fabrication, assembly, and installation information.

LOD500 “Operate/maintain it.”

More information about level of development can be found in the LOD Specification for Building Information Models. (

Shared Coordinates

In the collaborative process of sharing information via linked models, the coordinated positioning of each model is of paramount importance. Agreement on a common coordinate system and origin must be included in every PxP to ensure accuracy in model alignment and compliance with client requirements.

How does it work?

Usually, a survey plan or 3D topographic model will be provided by a civil engineer. This data will be referenced into the main architectural model within which the Shared Coordinates system will be established.

The main architectural model will then be linked into all other consultant models; the linked model can be placed as the consultant desires; and then the shared coordinates will be acquired from the linked architectural model.

Once all project models have acquired the shared coordinates from the designated architectural model, all exports for CAD, Navisworks, IFC, and so on, will possess the correct coordinate parameters.

Model-Based (3D) Coordination

At specific project stages (depending on the details of the PxP), it will be the responsibility of a multi-discipline firm to be self-coordinated BEFORE transmitting the models to HOK. For example, mechanical, electrical and plumbing models being prepared by one engineering firm must be coordinated with each other before integration with the architecture and structure models.

Subconsultants using Revit will be responsible for creating a Navisworks export, to be delivered with the original Revit files, according to the collaboration schedule set forth in the PxP. This requirement ensures that the Subconsultant retains responsibility for the model content exchanged from one platform to another.

About HOK’s template clash tests

HOK’s buildingSMART team has developed a series of template clash tests in Navisworks to facilitate 3D Coordination during design phases.

Within the HOK PxP template, the design team will agree to the clash tests to be conducted during the design phases. This will set the expectations for any other recipient of the design models, such as the builder or client.

In the example table below, note the Status column to the left. Each test is indicated with an “R” if it is required by HOK’s BIM Certified program, and/or “D” if the test is to be conducted within a discipline as mentioned above. If the test is not a required or intra-discipline test, the status will indicate either yes (Y) or no (N).

Clash Resolution

It is the responsibility of the Architect to supervise the 3D Coordination process; however, each Subconsultant must participate in the resolution of clashes in order to achieve the stated quality control goals of the project.

In addition to participation in inter-disciplinary clash resolution, Subconsultants are responsible for performing self-checks (intra-discipline) on model content BEFORE the models are transmitted to HOK. This means that there should be no clashes in testing structure versus structure; and HVAC versus HVAC; and so on.

Collaboration Technology

HOK employs several technologies to support an advanced level of collaboration with our extended design teams as well the owners and builders to whom we provide services.

Newforma Project Center

HOK utilizes Newforma Project Center and InfoExchange for all project management and collaboration. All design data artifacts are transmitted via the HOK InfoExchange site.
If your firm also utilizes Newforma Project Center, there may be opportunities to streamline the connection with an HOK project team via automatically synchronized project folders. Please contact the HOK Project Manager for more information.

Citrix XenApp

Most of HOK’s major offices maintain hardware that supports Citrix XenApp - a system that offers extended design team members on-demand secure access to enterprise applications. This tool eliminates the need to send large design files over the Internet. Instead, remote users can run software such as Revit via a web-browser without ever moving a file off the project server.

While this platform is not used on every project, it has proven to be extremely effective on large projects with design team members in various remote locations.


HOK’s enterprise solution for web-based conferencing is WebEx by Cisco. Project meetings can be conducted with many constituents with the options to use toll free phone access or the microphone and headset connected to the computer. Meetings can be recorded for future reference and played back with a free player available from the WebEx website.

For additional information, please contact
Modified Aug 4, 2014