Virtual, Augmented and Mixed Reality for Homebuilding Visualisation

Posted by Kuldeep Bwail on March 29th, 2017

There is a paradigm shift in the way homebuilders plan, design, construct and market their houses. residential architectural 3D rendering not only helps for the marketing and presentation process, it also streamlines the planning process, improves design communication, accelerates construction and enables informed decision making.

Typically, photorealistic images are rendered from a virtual 3D model and exported to a rendering software to bring life to the model by adding features such as textures, material, lighting and landscape to make the image photo-realistic. While photo-realistic images are still preferred, many homebuilding teams are embracing new immersive technologies to provide a tactile experience.

In large homebuilding teams, there are many stakeholders and the benefits of an engaging experience are not limited only to end users or buyers, it is also extended to the large team of builders, architects, designers, contractors and other stakeholders involved in materialising a project.

While architects and designers are responsible for home design which includes roof design, floor plans, elevations and room layouts, a larger team of contract staff is also employed to help with other building tasks such as HVAC and MEP (M&E) installation, groundworks, landscaping and decorating.

With the introduction of new technologies, virtual experiences are now designed to simulate the real world more realistically and enable the large team of builders coordinate, design, plan and implement efficiently. There is a shifting trend in architectural visualisation, from 3D residential architectural rendering to pre-rendered virtual reality and augmented reality models.

Behind the Scenes of Virtual Reality and Augmented Reality

On one side is the real world, on the other is virtual reality (VR) and in the middle, is augmented reality (AR) and mixed reality (MR) experiences. A combination of VR and AR enables the team of builders, architects, engineers, MEP (M&E) professionals, interior and landscape designers to streamline the design review process, identify areas of improvement and fine-tune the construction process.

While homebuilding architectural teams have been using 3D models and residential architectural rendering, the same models can be used to create VR and AR experiences. For architects, VR and AR enable creating a real-world experience of designs in accordance with standards established by clients. VR and AR also help designers showcase designs, floor plans, elevations, roof designs, room layouts and sizes in a real-world environment.

To understand the benefits of immersive technology such as VR, AR and MR, it is important to know how each work behind the scenes.

1. Virtual Reality (VR)

In a traditional 3D environment, applications such as Revit, AutoCAD and 3ds Max, are typically used to create a virtual 3D model. The 3D model is then optimised to be compatible, viewable and navigable in a virtual environment. Optimisation of a 3D model for VR and AR needs adjustment of various settings such as scale, camera placement, frames per second (FPS) and refresh rates typically using a rendering software such as V-Ray. Once the 3D model is optimised, the virtual environment is created using a rendering engine such as Unreal Engine. After these settings are made, pre-rendered VR content of 3D panoramic images and videos are ready for use on VR Head Mounted Displays (HMDs).

There are two types of VR devices available in the market today, tethered devices and mobile devices, that support an interactive VR and a still VR format respectively. To make sense of how it works, there are a few terms associated with VR HMDs that need to be understood:

• Pre-Rendered VR Content - Traditionally, when making pre-rendered VR content, the latlong (latitude-longitude) method was used that had only one seam along the longitude line. However, with higher distortion of latlong images, cubemaps are typically used to create a six-sided, 90-degree FOV image that efficiently represents 360-degree, panoramic images and videos.
  
  
• Field of View (FOV) and Camera Placement – Humans have a FOV of the world that spans around 220 degrees. To provide an immersive experience, HMD VR headsets need to offer a FOV as close to 220 degrees as possible. While a 360-degree image is rendered, to view what someone is likely to see when wearing a headset without turning their head, use a 90-degree FOV image. This will help in understanding where to position the camera in the virtual scene. To setup stereo cameras, V-Ray a rendering and simulation software offers a stereographic helper to adjust stereography parameters.
  
  
• Frames Per Second (FPS) – The number of images displayed per second is known as FPS. The rate at which the device or monitor refreshes is known as refresh rate and is measured in frequency (Hz). Ideally, 90Hz or 90 FPS needs to be maintained to ensure the output is smooth. While 120 FPS is the target for high-quality VR experiences, anything lower than 60 FPS leads to motion sickness as the user experiences considerable lag which is unsettling.
  
  
• Rotational Tracking – HMDscan track the orientation and direction in which the user is looking using motion sensors or gyroscopes,and map the pitch, yaw and roll rotation along all three axes. Mobile VR HMDs usually have rotational tracking with variable FOV of 90 degrees and maximum 60 FPS.
  
  
• Positional and Room-Scale Tracking – HMDscan track the position of users and sense whether the user is standing, sitting, kneeling or leaning forward. With room-scale tracking, HMDs can track the positions of users as they move freely in a fixed, virtual space. The Oculus Rift can track the position of users by monitoring a set of infrared LEDs on the HMD using an external webcam. The HTC Vive provides room-scale tracking using two sensors that are placed diagonally opposite each other in the corners of the room. There are other premium mobile VR HMDs that provide positional tracking with an FOV of 96 degrees and a consistent 60 FPS.

Among tethered HMDs, HTC Vive and Oculus Rift offer rotational tracking and positional tracking with FOV of 110 degrees and 90 FPS. Among the mobile HMD versions, Google Cardboard is suitable to view 360-degree images for entry level experiences. Samsung Gear VR, compatible only with Samsung phones and the recently provide better functionality and VR experience compared to Cardboard. Whereas Oculus Rift, HTC Vive and the recently launched Sony PSVR provide a more holistic VR experience.

For a homebuilding team, VR is very useful in providing a virtual perspective of a space, allowing architects and designers to make faster design approvals and speeding up the design process. VR is also an effective marketing tool, as it provides an immersive experience to buyers, allowing them to experience what a house is likely to resemble even before it is constructed.

Given the ever-evolving trend of using new immersive technologies, virtual reality is widely being adopted to bring 3D residential architectural renders to life by creating a virtual scene of the completed project. By optimising 3D model data to make it compatible with a virtual environment, a virtual experience of a space that is not yet constructed can be visualised. Taking VR a step further for creating immersive experiences, introduces augmented reality (AR) which is another concept that adds a virtual dimension on the existing environment.

1. Augmented Reality (AR)

If VR brings virtual pixels to life, AR adds a dimension of information or virtual computer-generated images over an existing real environment. In the AEC industry, AR application and implementation is still in the nascent stages. For large homebuilding teams, AR helps in better coordination between different stakeholders which needs to happen at the outset to improve design approval by reducing design errors, and therefore avoid delays and ensure lower costs.

AR as a Marketing Tool

AR when used by buyers as a marketing tool, provides a 360-degree view of a completed project overlaid on a 2D elevation drawing or 3D model. The camera of a smartphone is used to scan a 2D drawing, a virtual 3D model or the actual site. Once the camera of the smartphone or device is focused, the app recognises the plan or model and overlays a virtual model of the completed project on the screen. The benefit of providing a potential customer with an AR experience for a home that they are interested in buying can be priceless.

AR as a Project Management Tool

Application of AR technology in the pre-construction phase helps in streamlining the process for designers, architects, contractors and engineers. Architects and designers use AR to simulate design scenarios by interacting with virtual models, making it easier to modify designs and make decisions.

Project managers can use AR headsets onsite through virtual walkthroughs to monitor different building teams such as general contractors, MEP contractors and engineers. With AR technology, it is possible to view the build site virtually with BIM overlays and identify issues. Normally, these issues, clashes or errors are identified in hindsight, leading to expensive rework and renovations.

By using AR headsets such as Microsoft’s HoloLens or Daqri’s Smart Helmet, contractors and consultants can thoroughly scan the building to ensure all facilities are installed accurately and that clashes and errors are avoided before installation. Even after construction of a building, AR is useful in maintenance by enabling workers to identify problems on the go while walking through the real building environment.

1. Mixed Reality (MR)

When VR and AR are combined, what is experienced is a mixed reality. While VR and AR have become mainstream, there is a thin line between the virtual space and the real environment. In mixed reality, there are objects and places blended from the physical world with virtual environments. Mixed reality creates interactive holograms that enable working with digital content in a real-world environment.

MR has transformed the way people work, plan, communicate, coordinate, explore and will ultimately affect the way homes are marketed to the end customer. Responsive holograms enable homebuilders to understand their projects in relation to the real-world environment, making it easier to make smarter decisions, fine-tune design, improve seamless coordination and ensure efficient project management and implementation.

Taking 3D BIM Coordination to The Next Level with VR and AR

Based on current trends, architectural rendering service providers are moving from colour 2D elevations to residential architectural rendering and object-oriented 3D models that are embedded with details and information on objects and the project, known as BIM models.

BIM (building information modeling) models provide geometrical information as well as other data such as the type of material of various objects, system quantity, size, shape, location and orientation, detailing fabrication, assembly and installation information. BIM coordination enables the team of builders with essential information such as HVAC and MEP specifications, lighting settings, cost estimation with the bill of quantities (BOQ), project sequencing and facilities management. While homebuilders are extensively adopting new immersive technology, integration and optimisation of BIM models for VR and AR technology is still being developed.

Based on emerging industry trends, the next decade is likely to see virtual reality and augmented reality become adopted much more widely in the construction industry. By integrating 3D BIM coordination with VR and AR, homebuilders will get a sophisticated marketing tool that will also help architects, designers, contractors, engineers and the entire building team work collaboratively in an efficient manner.

Read more about How VR, AR and Smart 3D Rendering Can Help Homebuilders Make Homes Better in our next article.