STRATUS: A Private Cloud Server Technology for Revit

Des Pudney
CIO, Stephenson & Turner New Zealand Ltd, Architects and Building Services Engineers

Introduction

Stephenson & Turner (S&T) is a medium-sized, multi-disciplinary, Architectural and Building Services Engineering practice based in New Zealand, with offices located in Auckland and Wellington.  Originally established in Australia in 1920, S&T has been part of New Zealand's business community for more than 50 years. During that time, the company has helped shape New Zealand's architectural landscape, with an extensive portfolio of successfully completed projects.  S&T now works with clients and associates on a wide range of projects throughout New Zealand and the Asia-Pacific, including a steadily increasing number of BIM-based projects.

S&T has developed and implemented a Private Cloud-based technology named STRATUS for the delivery of Autodesk Revit as an online service (see Figure 1). STRATUS has been operational for the past 12 months, with immediate and tangible benefits for the company and its clients.  This article describes the background and rationale for S&T’s STRATUS development, and discusses additional details including the technology’s features and the benefits afforded by STRATUS to the firm.

Background of STRATUS Development

The development of STRATUS can be traced back to 2006, when S&T successfully applied to the New Zealand government for a “Foundation for Research, Science and Technology” funding grant.  This funding module enabled the company to embark upon a research program that was focused on supporting S&T’s implementation of BIM. This research included the evaluation of remote computing technologies to assist with the rapid deployment of Autodesk Revit over LAN and WAN connections.  The company’s 2006 studies highlighted that 3D-Graphics remote computing was not a feasible option due to the relatively poor performance of remoting protocols available at that time.  The company made the decision to shelve further research in this area until these technology barriers could be overcome at some point in the future.

In 2009, the company’s remote computing initiative was reinstated. Various emerging developments in 3D-Graphics remote computing technologies prompted this move, including developments by Calista Technologies (since acquired by Microsoft) and Teradici (now in a co-development agreement with VMware).  The options explored included technology packages from VMware, Citrix, Quest, HP and Microsoft.  The technology from Microsoft soon emerged as the leading contender and was promoted to the level of a proof-of-concept study, at the conclusion of which the firm’s owners decided to invest in the development of STRATUS to support the Revit team production environment. 

Some of the technical challenges and IT-related issues that needed to be overcome for the STRATUS Cloud development were:

• Disparate locations: The key to the STRATUS project from an IT perspective was ensuring that all remote Revit users could successfully access the Revit applications and Revit project files from their location.
• Security: Due to commercial sensitivity of the Revit projects that would be hosted by the STRATUS Cloud, best practice security measures had to be implemented.
• Authentication: As there would be many remote Revit users accessing the same STRATUS resources, authentication would need to be centrally managed.
• Resiliency: STRATUS had to be resilient as any downtime would be extremely disruptive to the remote Revit user’s project time frames.

Within a few weeks following the implementation of STRATUS, it was driving all of S&T’s active Revit projects. The STRATUS deployment quickly expanded to include a number of multi-office collaborative Revit-based projects being run over WAN links.  Early 2011 saw a quadrupling of the company’s STRATUS capability in order to address the burgeoning increase in S&T’s demand for Revit-based remote computing.

Data Center Infrastructure

The STRATUS Private Revit Cloud is hosted on multiple servers located in Auckland and Wellington data centers.  These servers are configured in high-availability farms so that should one server go offline, the other servers will still allow connections. The Auckland and Wellington data centers are linked by dedicated high-speed VPN tunnels, and have been designed as fully redundant failover systems. The STRATUS Cloud architecture is illustrated in Figure 2.

Access to the STRATUS Revit Cloud is controlled and load-balanced by the STRATUS Broker, shown in Figure 3.  The primary role of the Broker is to ensure that Revit users do not consume an excessive level of STRATUS system resources to the detriment of the other concurrently connected Revit users.  When a Revit user connects to STRATUS, the Broker connects the Revit user to the STRATUS server that has the least number of live connections.

STRATUS has been designed to be completely modular and scalable. By simply adding additional servers into the STRATUS farm, the Private Cloud infrastructure can be scaled to accommodate any increase in the number of remote Revit users.  The STRATUS infrastructure presents a “virtual pool” of system resources (see Figure 4), comprising multi-threaded dual Hex-Core CPUs with multiple gigabytes of RAM and GPU. This virtual system resource pool ensures that any STRATUS Revit user can confidently work with large Revit project files in the Cloud without the risk of system failure.

As STRATUS is a data centre based infrastructure, S&T’s Cloud investment has become a highly utilized computing asset that is leveraged across the entire organization, helping to deliver a significant return on infrastructure and licensing investments.  Moving forward, investment in S&T’s desktop computers will be at a significantly reduced cost as the desktop computer in effect becomes a thin-client interface between the Revit user and the Cloud.

Remote Application Delivery

The STRATUS Revit applications are accessed via a secure HTTPS website, meaning that Revit users only need connectivity to port 443 (HTTPS) to allow a connection. The STRATUS website permits Revit applications to be launched from the Revit user’s web browser on their local computer.  All published Revit versions are controlled by security permissions to ensure that only the correct version and build of Revit is presented to each Revit user according to their specific Revit project requirements. The STRATUS website sign-in screen is shown in Figure 5, and all of the applications that a particular user has access to after logging in are shown in Figure 6.

STRATUS delivers Revit to the user as a Remote Application. This remote application consumes the system resources of the STRATUS Cloud servers, not the resources of the Revit user’s local computer. The STRATUS Revit Cloud presents an opportunity to re-provision any low end computing hardware as a STRATUS thin-client computer that can be deployed for the purposes of modeling large and complex Revit projects. 

The current STRATUS development is optimized for any remote Revit user with an Internet connection utilizing a local computer running Windows 7, Windows Vista, or Windows XP Pro operating systems.  STRATUS has also been successfully demonstrated on Apple’s iOS iPhone and iPad devices (see Figure 7), and a deployment capability to support Apple Mac OS is planned for 2011.

Geographically Distributed Revit Modeling

Geographically distributed Revit user teams can easily and securely collaborate over the public Internet using the STRATUS Private Cloud. The available bandwidth and latency of a remote user’s WAN connection will dictate the number of concurrent STRATUS users at the remote office.  S&T has found that 100-400 kbs of bandwidth is required for each connection depending upon the specific activity of the remote Revit user. Latency between the remote user’s office and the STRATUS data center should ideally be less than 50ms to ensure that the Revit remote-application response time remains unobtrusive to the remote user’s experience.

Australian-based STRATUS test sessions have been conducted back to the New Zealand-based STRATUS Cloud without any significant performance degradation.  STRATUS has demonstrated the capability to deliver Revit modeling access to a geographically distributed and mobile Revit-based workforce.

Comparing S&T’s STRATUS Cloud with Autodesk’s Revit Server

With S&T’s STRATUS Cloud, the Revit application and the Revit files both reside in the STRATUS Cloud data center. Remote Revit users connect to the STRATUS Cloud to access their Revit applications and Revit files, irrespective of their physical location, assuming the minimum requirements for WAN bandwidth and latency are met. The STRATUS-based Revit applications consume the system resource of the STRATUS Cloud servers, which far exceed those of any typical personal computing hardware. The Revit files remain secure in one location, supported by a comprehensive disaster recovery plan with fully redundant failover systems. 

In contrast, Autodesk’s newly introduced Revit Server uses Revit applications installed on the Revit user’s personal computer, consuming the relatively finite system resources of the user’s local machine. The Revit model files do not reside on one file server; rather, with Revit Server, several offices are connected together with Revit Server responsible for replicating central files to each office and keeping them coordinated.

Well before Autodesk released Revit Server, S&T had already deployed STRATUS Private Cloud for Revit. While S&T had 2 offices that needed to access the same Revit models, their needs had also evolved to remote and mobile access for S&T staff, consultant access, and several other situations where access to Revit files was needed by people in all kinds of locations. Now, any of S&T’s STRATUS users can access their Revit application and Revit models from any device that is connected to the Internet.  The author has personally accessed 500+MB Revit models from a laptop, iPad and even an iPhone. The challenge is that the needs of S&T’s Revit users keep evolving, so the agile technology of the STRATUS Private Revit Cloud enabling a remote and mobile Revit workforce is a significant advantage.

Depending on your company’s situation, Autodesk’s Revit Server may very well cover your requirements. If your requirements go beyond Revit Server, then a Private Revit Cloud project like STRATUS might well be on your company’s IT strategy roadmap.

Conclusion

The benefits of STRATUS to S&T’s Revit users in the production environment have been both immediate and compelling. Since the introduction of STRATUS, S&T’s Revit users have been able to work from any New Zealand Internet-capable location, modeling large Revit files with 100% application stability and with significantly faster processing speeds irrespective of file size.  Further benefits continue to be uncovered as S&T continues to refine its STRATUS development, particularly in response to feedback received from their Revit users. 

S&T’s development and deployment of the STRATUS Private Revit Cloud has been a positive game-changer for the company and has completely redefined their thinking and approach to the delivery of Revit to their project teams. The STRATUS team is in the process of developing the next version of this technology to ensure that S&T remains at a leading edge in their use of Private Cloud technology to underpin their BIM capabilities.

In conclusion, S&T’s experience has shown that numerous business benefits can be afforded to a firm by the implementation of a Private Revit cloud. These include the ability to work effectively with large Revit files, with higher levels of application performance and stability, and the enablement of remote and mobile workers. S&T seized the opportunity to develop this technology for the firm’s private use. It was fortunate to have the in-house knowledge and skill to do this. This type of do-it-yourself innovation approach is typical of many New Zealand organizations. For those AEC firms that wish to take advantage of the benefits of Private Cloud but lack the in-house skills and capital budget required to build this capability themselves, they could explore the services provided by private Cloud-hosting firms.

About the Author

Des Pudney is the CIO for Stephenson & Turner New Zealand Limited and is based in Auckland, New Zealand. He has specialized in Information Technology for the last decade and has been actively involved in the Architecture and Engineering consulting sector for over 20 years.  Prior to becoming CIO at S&T, Des has held ICT and CAD Manager positions.

As CIO of S&T, Des leads the firm’s ICT strategy, planning, and operations.  He also works with clients and other design consultants to ensure their technologies successfully interface with those of S&T to facilitate a streamlined collaborative BIM environment.

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