UNIT-3 SOFTWARE TECHNOLOGIES ||LONG QUESTION ANSWER ||AR & VR AKTU NOTES

 LONG QUESTION ANSWER

Q1. What is the use of Lights and Cameras in VR environment?

Ans.Lights- In the real world, lights provide illumination so that you can view objects. If a scene graph does not contain any lights and you’re using the phone lighting, the objects are in darkness and cannot be seen. Just as the real world provides a variety of illumination types-light bulbs, the sun, theatrical spotlights as many like inventor provides different classes of lights for you to use in your scene.
Cameras- Cameras are our “eyes” for viewing the scene. Inventor provides a class of camera with a lens that functions just as the lens of a human eye does, and it provides additional cameras that create a 2D “snapshot” of the scene with other kinds of lenses.
During filming, stereoscopic VR utilises 2 lenses for each angle as apposed to 1. The 2 lenses represent the human eyes and they capture similar information.Using the VR Camera to mimic human eye positions, stereoscopic VR creates a sense of 3D depth in 360 videos, with objects appearing nearer or further away.

Q2. What is Hardware control?

Ans.The VR hardware accomplishes this by using sensors for tracking motions of user such as button presses, controller movements, eye and other body part movements. It also considers the physical surrounding world because only engineered hardware and software does not constitute the complete VR system. The organism (users) and its interaction with the hardware is equally important.
VR hardware constitute of sensors which act as transducer to convert the energy it receives into a signal from an electrical circuit. This sensor has receptor to collect the energy for conversion and organism has sense organs such as eyes and ears for the same purpose. As the user moves through the physical world, it has its own configuration space which are transformed or configured correspondingly.

Q3. Write short note on:

1. Geometery
2. Position/Orientation
3. Heirarchy
4. Bounding Volume

Ans. Geometry:A geometric shape is the geometric information which remains when location scale, orientation and reflection are removed from the description of a geometry object. Such shapes are called polygons and include triangles, squares and pentagons. Other shapes may be bounded by curves such as the circle or the ellipse. Objects that have the same shape as each other are said to be similar. If they also have the same scale as each other, they are said to be congruent.
Position/Orietation:Position is defined with respect to where the object or tool (rigid body) is located in space. Whereas, Orientation is how it is oriented e.g. Whether inclined with respect to something or maybe aligned with it, maybe rotating with respect to a reference frame (RF0) and now generating a new reference frame (RF1) due to rotation.
We can understand both position ,orientation with an example which is: Imagine a coordinate system placed in front of you with x-axis in red, y-axis in green and z-axis in blue(imagine you are in Virtual Reality). Now the origin of the coordinate system is placed at about 1 meter from the center point of your eyebrows with its x-axis pointing towards you. Now, when you ask for the position or orientation of this frame, it has to be always with respect to some other reference frame, normally referred as inertial frame of reference. In our case imagine a reference frame at the center point of your eyebrows with its x-axis pointing towards. So, the position of the first frame is the distance of its origin from the reference frame which is 1 meter and the orientation how it is rotated with respect to the reference frame, which in our case is 180 degrees rotation about z-axis.
So, always remember that position and orientation are the properties of a frame (coordinate system) associated with any rigid body (an object).
Hierarchy:

• Comfort-Comfort encapsulates some very basic requirements, many of which concern the accurate rendering of the simulated environment in immediate response to head and bodily movements. This level is all about meeting our deeply unconscious expectations about the nature of our sensory inputs, and how they interact with our actions. It is largely the responsibility of the VR hardware such as the HMD and graphics processor, as well as the engines used to author and render the content or application.
• Interpretability-Interpretability describes our need for the simulated environment to make sense. VR can certainly bend some of the rules of physics: we can fly, exhibit super-human strength, and even warp time and space. But these enhanced experiences must be quantitative and metaphorical extensions of normal life, rather than completely de novo creations.
  Another way to think about Interpretability is that, of all the stimuli that we can create with VR systems, only a vanishingly small fraction of them will make any sense at all to our perceptual systems. The better we understand the rules that govern these constraints, the more efficient e’ll become in creating immersive environments
• Usefulness - Usefulnessis a highly application-specific concept, but it really comes down to value: did the VR experience deliver on its basic value proposition? Did the movie tell a story that made sense? Did the tele-presence session enable rich, high-fidelity communication?
• Delight- Delightis the realm of artistry. Did the movie leave you thinking for days afterward? Was the tele-presence session almost as good as visiting with family in real life? We earn the right to strive for Delight by first conquering the lower-level needs through engineering, craftsmanship, and attention to detail.

Example: As take the example of Hierarchy to do Manipulation task: Step 1 : Navigation
Step 2 : Selection
Step 3 : Set a Position (Direction)
Step 4 : Manipulate an object

Bounding Volume: A bounding volume for a set of objects is a closed volume that completely contains the union of the objects in the set. Bounding volumes are used to improve the efficiency of geometrical operations by using simple volumes to contain more complex objects. Normally, simpler volumes have simpler ways.

Q4. Explain all the VR devices in Hardware and Software both?

Ans: VR devices-VR devices are the hardware products used for VR technology to perform the task. The different key components of VR system are discussed below. The figure (number) shows the high-level view of Virtual World Generator (VWG). The inputs are received from the user and his surroundings and appropriate view of the world are rendered to displays for VR experiences.

• Hardwares :
  • Personal Computer (PC)/Console/Smartphone-

    Computers are used to process inputs and outputs sequentially. To power the content creation and production significant computing power is required, thereby making PC/consoles/smartphones important part of VR systems. The VR content is what users view inside and perceive so it is equally important as other hardwares.

  • Input devices:
    Input devices provides users the sense of immersion and determines the way a user communicates with the computer. It helps users to navigate and interact within a VR environment to make it intuitive and natural as possible. Unfortunately, the current state of technology is not advanced enough to support this yet. Most commonly used input devices are joysticks, force Balls/Tracking balls, controller wands, data gloves, trackpads, On-device control buttons, motion trackers, bodysuits, treadmills and motion platforms.
    
    
    
    
    

  • Output devices:

    Devices that each stimulate a sense organ. Output devices are used for presenting the VR content or environment to the users and it is utmost devices to generate an immersive feeling. These include visual, auditory or haptic displays. Like input devices, the output devices are also underdeveloped currently because the current state-of-art VR system does not allow to stimulate human senses perfect ideal manners. Most systems support visual feedback, and only some of them are enhanced it by audio or haptic information.

• Softwares :

  Apart from input, output hardware and its coordination, the underlying software is also equally important. It is responsible for the managing of I/O devices, analyzing incoming data and generating proper feedback. The whole application is time-critical and software must manage it input data must be handled timely and the system response that is sent to the output displays must be prompt in order not to destroy the feeling of immersion. The developer can start with basic software development kit (SDK) from a VR headset vendor and build their own VWG from scratch. SDK usually provide the basic drivers, an interface to access tracking data and call graphical rendering libraries. There are some ready-made VWG for particular VR experiences and has options to add high-level scripts
  Audio - Virtual reality audio may not be as technically-complex as the visual components, however, it is an equally important component to stimulate a user’s senses and achieve immersion. Most virtual reality headsets provide users with the option to use their own headphones in conjunction with a headset. Other headsets may include their own integrated headphones. Virtual reality audio works via positional, multi-speaker audio (often called Positional Audio) that gives the illusion of a 3-dimensional world. Positional audio is a way of seeing with your ears and is used in virtual reality because it can provide indications to gain a user’s attention, or give them information that may not be presented visually. This technology is already quite common and often found in home theater surround sound systems.

Q5. What is VR toolkits?

Ans. VRTK: VRTKis a collection of useful, reusable solutions to common problems found when building for virtual reality. VRTK aims to help productivity by speeding up the creation process from prototyping ideas to building complete solutions.
VRTK is an open source codebase that allows users to drag and drop functionality. By being able to drag and drop Assets into Unity 3D, with a few configurations, they can immediately open example scenes with ready-set fully functional essential gameplay mechanics such as locomotion, a variety of user interfaces, and physical interactions around which you can start building your game.
The major benefits to this toolkit are that it’s the only one of its kind that is readily adaptable to any hardware on which you plan to develop: Oculus + Touch controllers, HTC Vive, mixed reality (MR) headsets, mobile VR headsets. Because hardware accessibility can be a barrier to many aspiring or new VR creators, the default of its use includes a VR simulator.
The most important piece of a virtual reality kit is the headset, a device like a thick pair of goggles that goes over your eyes. The more expensive, higher quality headsets need to be connected to a computer to run apps and games, while some cheaper ones use a cellphone clipped to the front of the headset.
There are some VR tools are as below:

DESKTOP TOOLS:This is a collection of tools VR developers are using to create native application experiences, typically for Windows machines.

• Unity 3D

  Unity is by far one of the most ubiquitous of tools being used today for VR development. At its heart, it’s a game engine. It has a direct VR mode to preview your work in an HMD (Head Mounted Display) which can really boost productivity by designing for VR within a virtual environment.

• Unreal Engine (UE4)

  One of the main competitors of Unity 3D, Unreal Engine is also a gaming engine with VR integrations, an asset store, and great documentation. The graphics are debatably more advanced and realistic and the learning curve is similar to Unity. Many of the VR demos built with UE4 are much more life-like and smoother to navigate within.

• 3DS Max & Maya

  These are Autodesk products for modeling, animation, lighting, and VFX. They don’t have VR support by default but through pricey plugins instead. AutoCAD and 3DS Max are long-time standards in the architectural design industry and have some of the most precise tools in their UI.

• Blender

  Blender is quickly becoming a favorite modeler for many VR developers. It’s free and open source software written in Python and is available for Windows, Mac, and Linux. There’s a huge community of people devoted to this software and its use. Many websites provide tutorial videos, forums, and documentation

• SketchUp

  Google’s SketchUp is a basic modeling application with a very low learning curve that can get anyone up and running in a short amount of time. The tutorials on the website are excellent, not only teaching the basics of the software but also as introductory lessons to basic 3D modeling concepts.

Q6. What is LODs, Cullers and Occluders?

Ans. LODsVirtual reality systems often employ various performance optimization techniques. One of the most popular methods is using geometric models with different “Levels of Detail (LOD)”.
Occluders-Occlusions limit what the user can see from a given location, and the user has to navigate the viewpoint around occluders to gain line of sight to the hidden parts of the scene.