3D Visualisation made possible with Virtual Reality (VR)
Virtual Reality (VR) is becoming increasing popular as it gives the experience of being fully immersed within an interactive 3D environment. It requires the user to wear a device such as Oculus Rift, Google Cardboard or Samsung Gear. Google Cardboard requires a smart phone to be placed inside the viewer and can fit a range of mobile devices that run either Google Android or Apple IOS whereas Samsung Gear only fits Samsung products. Oculus Rift has its own display built in and requires a connection to a PC for it to run. Microsoft has also released a Virtual Reality device called HoloLens. The key difference between the likes of Oculus Rift and HoloLens lies with the user experience. Oculus Rift makes the user feel as if they are inside a virtual environment where as HoloLens can bring the virtual world to them by placing virtual objects in the real world.
Google Cardboard can display pre-rendered images or videos that are static, with the ability to look around in any direction but from a fixed or controlled point in space. Viewing real-time content is also possible where objects, lighting and reflections are dynamic as opposed to static. This allows for more realistic effects such as parallaxing. Developing content using game engines such as Unity3D or Unreal Engine would allow a user to freely walk around in a virtual environment and not be fixed to a pre-rendered point or path. The benefit Oculus Rift has over Google Cardboard is the ability to display higher quality graphics and better interactivity in real-time. However due to the simple design and setting up of Google Cardboard it is ideal for showing off the latest architectural visualisation.
Google Cardboard displays static content in either mono or stereo format. Mono has no depth and objects will appear very flat inside VR. However it is easily viewable on a PC or mobile device where VR is not an option. But by viewing in stereo format inside VR, the user experiences a level of depth and the environment suddenly becomes more real. Back in 2014 Framestore, the British visual effects company made it possible to take the elevator at Castle Black and then ascend “The Wall” from the popular TV series Game of Thrones. It was created using Oculus Rift and Unity3D combined with a physical cage to stand in and wind blowing around for good measure. For it be as real as possible the computer hardware used to run the VR content was extremely powerful, running real-time 4K content at 60fps.
VR content is now more accessible than ever
Images or videos must be in a specific format to work with VR. One of the most common is a 360° spherical panoramic which shows the entire environment in any direction within a single frame. Some 3D rendering software, for example Chaos Group V-Ray, have been able to produce spherical panoramic renders for some time but there has been little support for viewing a full 360° animation. Since the buzz began about VR it prompted a wave of viewing software such as YouTube who since March 2015 have fully supported the uploading of 360° Videos in mono format and stereo. There is alternative software such as the krpano Panorama Viewer that has a whole range of customisable features for both mono and stereo, such as adding hot spots to move from one content to another just by focusing on an icon within the VR. For example rather than an animation which could take a long time to render, multiple images could be linked together at specific points within an environment. They could be close together allowing the user to navigate stepping stones or they could be further apart for each room within an interior. This can be seen in our demo.
Important factors to consider when opting for VR
It is important to match the content with the user’s Interpupillary distance (IPD). This is the distance between the centre of the pupils and it should match up with the distance between the lenses of the VR viewer. The official Google Cardboard comes with a fixed IPD of 60mm using a 45mm focal length. However Oculus Rift can automatically set the recommended IPD when in use. If the IPD is different it may force the user to look continuously crossed eyed causing a strain on the their eyes. There are 3rd party Google Cardboard alternatives that incorporate adjustable lenses for matching varying IPD’s. These come in either cardboard or slightly up market foam and plastic versions. Also bear in mind the physical size of the mobiles devices display will affect performance. If the lenses are too small it may be difficult to see the entire display.
Another consideration when viewing VR content is the frame rate per second (fps) of which it is played back. Most current mobile devices have a low frame rate causing content to judder as the user pans around. This is because there are not enough frames between looking in one area and quickly looking at another causing latency issues, which can lead to motion sickness for some users. However this will certainly get better as development for mobile devices improves. The benefit of Oculus Rift being plugged into a PC is the increase in frame rate. The current DK2 (development kit) version can reach up to 75fps. The consumer version due to be released in Q1 2016 will support up to 90fps giving a much smoother experience. Sony’s VR headset named Morpheus boasts 120fps and is due to be released in 2016.
Cost effective yet powerful GPU rendering with NVIDIA & V-Ray RT
Due to the increase in render times required to produce VR content, we aim to render all of our Virtual Reality projects using Chaos Group V-Ray RT using NVIDIA CUDA technology. Rendering is completed quicker than traditional CPU rendering as GPU’s are more powerful. Not only is it much faster it can also be more cost effective to render in this way. Multiple GPU’s can be stacked inside a single workstation saving both space and cost with most renderers now having per node licensing in place.
Final thoughts on VR
Google Cardboard offers a simple and cost effective solution for experiencing Virtual Reality. Although it may not offer the same level of quality as Oculus Rift, it does have its advantages. Being flat packed, it is far easier to get content to the end user without the need for a powerful machine and it works with the majority of mobile devices. Not to mention it can be custom branded as Google have made their template available to download for free. As playback on mobile devices improves, the fps will certainly increase providing a much smoother experience.