CPD 11 2018: Virtual desktop infrastructure

INTRODUCTION

There are many reasons why a growing number of companies are moving over to virtual workspaces, also known as the “digital workspace”.

Factors for consideration include the ease of managing the system, lower running costs, a better use of resources and streamlined operations and mobility. In recent years, many of the issues that previously held back an enterprise from moving to the digital workspace have been addressed as the technology has matured.

瘦客户机——有效地集中管理的计算机，没有硬盘或磁盘驱动器——现在能够处理高级图形、Internet协议语音和视频流等元素，使它们更好地适应作为企业资源运行。

However one of the major drivers for virtual desktop technology within the architecture, engineering and construction industry is the growing shift to Building Information Modelling (BIM) models, primarily although not exclusively through the use of Autodesk Revit. AutoCAD drawings historically used many smaller files to create a tiered CAD project model.

WHAT IS REVIT?

Revit is a single application built for BIM with features for architectural design, MEP (mechanical, electrical and plumbing) and structural engineering and construction.

However, Revit is not BIM. Revit is built for BIM. Revit and other applications made for BIM help designers to design, simulate, visualise and collaborate in order to capitalise on the advantages of the interconnected data within a BIM model.

The key word in BIM is “information”. BIM is centred on models made up of objects. Revit creates these objects, which consist of data, which designers can see in different views – 2D drawings, 3D models and schedules, or lists. When one piece of data changes in one view, it is updated in all other views automatically by Revit because each view is displaying the same data.

对象也可以与其他对象相关。同样，如果一个对象发生了变化，任何相关的对象也会反映这些变化。

SHIFT TO BIM

The move to BIM allows different disciplines to work on their specific specialist areas independently. With BIM and Revit files, the numerous and unique disciplines are combined into a single multi-layered file.

However, just the sheer size of these creates problems for IT infrastructure, and when different companies need to collaborate on a project and share files, it can clearly be seen that BIM adoption has led to a variety of technical challenges.

Fortunately, the timing of Virtual Desktop Infrastructure (VDI) coming to maturity has coincided with BIM Level 2 adoption, therefore providing an answer to the file handling challenges.

The general industry consensus is that CAD is moving from 2D to 3D, with 4D (time analysis), 5D (cost management) and finally 6D (facilities management) being not too far in the future. As BIM models grow in size due to the increase in content the technical challenges will continue to mount up on companies using traditional IT desktop infrastructures.

BIM collaboration is fast becoming a major driving force behind enterprise purchasing decisions, and a virtual workplace is well suited to accommodating this trend.

A virtual workflow is able to follow a user around, allowing tasks to be performed wherever they are located without losing the thread of what they were working on and without having to wait for a system to boot up. Users are then able to search the cloud for those files that they had open on their regular PC.

Coupled with an access control token or single sign-on (SSO) solution, a simple touch of the wrist or swipe of a card will almost instantly open the user’s profile, revealing what they were working on last time they tuned in.

ADDITIONAL BENEFITS

In addition to these collaborative benefits, the government’s 2011 Construction Strategy defined four levels of BIM and mandated in the 2016-2020 revision that any company working on government projects is contractually obliged to adopt BIM Level 2, if projects are centrally funded.

The long-term strategy for the UK is set out in the Construction 2025: industrial strategy document, published in 2013, and sets a forward-looking view of how the industry and government will collaborate in order to put the UK at the forefront of global construction.

Numerous references to “Digital Built Britain” within the various documents that make up the stages of BIM adoption state a target for “increasing maturity of BIM level 2 to a point that supports development of BIM level 3 at a later date” by 2020.

Reading between the lines, industry consensus is that the mandated adoption of BIM Level 3 is targeted for 2025. Level 3 BIM represents full collaboration between all disciplines by means of using a single, shared project model that is held in a centralised repository, allowing all parties to access and modify the same model, removing the final layer of risk for conflicting information.

This is commonly known as “Open BIM”. Current nervousness in the industry around issues such as copyright and liability are intended to be resolved – the former by means of robust appointment documents and software originator/read/write permissions, the latter by shared-risk procurement routes such as partnering.

The Construction Industry Council’s BIM Protocol makes provision for these. The adoption of BIM Level 3 is significant since it will implement a markedly different process of project participants updating a single, shared integrated building model in real time. As things stand today the only way to deliver this solution with the technical performance required to drive a multitude of very large files is VDI.

ENVIRONMENTAL CONSIDERATIONS

Virtual workplaces are also better for the environment, with market analysts at research firm Gartner estimating that the IT industry contributes a 2% share of total global CO₂emissions. Recent studies conducted by the Fraunhofer Institute for Environmental, Safety and Energy Technology in Germany revealed that a combination of IGEL thin clients and virtual desktops based on VMware View software (a commercial desktop-virtualisation product) proved to have 47% less environmental impact than a similar, PC-based environment.

Furthermore, a virtual desktop infrastructure created especially for BIM users is far cheaper to purchase and run than a high-end CAD modelling workstation environment, with thin clients costing substantially less than their “fat” counterparts, and running at as little as 1 watt of power when idle.

瘦客户机的耗电量平均比PC少61%到77%，相比之下，瘦客户机的成本平均比“胖”PC低30%到50%——这还没有考虑到虚拟环境的较低总成本。

ADDITIONAL DATA

Revit models support up to eight users working in the same BIM model – VDI provides the ability to deliver this access to subject matter, experts and various other types of CAD user located across different physical locations with ease.

Revit requires low network latency, so the workstation needs to be on the same Local Area Network (LAN) as the BIM data. VDI is the only answer to many of these issues, since if users are to collaborate from all parts of the world, they all need to be accessing Revit applications on the same LAN as the actual BIM data.

建议VDI客户端与保存虚拟桌面和BIM数据的数据中心之间的延迟时间为180 ~ 200毫秒。

A typical VDI client uses 300Kbps of bandwidth to deliver comparable high-end workstation performance and seamless adoption.

VDI的最佳实践是使用1:4的物理CPU和虚拟CPU，这意味着四个虚拟桌面可以共享一个物理CPU，这再次节省了成本。