Open Source Software for Creating 3D Visuals

An open Source Software for creating 3D Visuals and example for possibility of using Smartphone for Physics Education

Abstract

There are many students who cannot understand concepts and ideas in physics only with plane static diagrams. The understanding of processes, dynamic phenomena or geometric relations can be enhanced with the use of computer animations POV-Ray is a freely available 3D rendering open source package which has the potential of creating animations not only for physics education but in general for science and technology education. The focus of this paper is the use of POV-Ray to create 3D animations and 3D static illustrations to visualize the packing arrangements, voids and crystal structures which are compulsory in solid state physics curriculum in undergraduate physics and explore the possibility of introducing them to use in smartphones.

1. INTRODUCTION

Computers today play an important role in acquiring and applying scientific knowledge, facilitating the learning process. There has been growing research interest in studying the impact of ICT on educational processes, in parallel with the expansion of easy access to many learners around the world [1-4]. Animation plays a major role in ICT based education and it has been demonstrated that animations serves several instructional roles such as attracting and directing attention; simulating dynamic processes and complex phenomena [5,6].As many students are not able to understand 3D environment properly, it very common, crystal structures are explained using commercially available plastic models in many classrooms. Solid State Physics (Condense Matter Physics) course which is compulsory for physics students throughout the world, one of the learning outcomes is underrating crystal structures. Students often fail to understand close packing arrangements, shape and nature of the existing voids, number of atoms around and separation of layers by looking at a plane static diagrams accommodated in text books. These particular animations have been chosen not just because of their solid state physics curricular interest, but also to highlight the potential of integrating the POV-Ray rendering package for physics education and science education.

As the smartphones are no longer unaffordable luxury gadget for the students, educators embrace the smartphonesto engage with their students and encourage new learning strategies[7-9].The smartphones users are rapidly growing among Sri Lankan undergraduates 3D visual created in this study were checked on smooth playing on smartphone with the intension of distributing among the students in the future.

1.1 POV-RAY OPEN SOURCE

POV-Ray stands for the Persistence of Vision Ray-tracer, a tool for producing high-quality computer graphics[10].Ray-tracing is a rendering technique that calculates an image of a scene by simulating the way rays of light travel in the real world. In the real world, rays of light are emitted from a light source and illuminate objects. The light reflects by the objects or passes through transparent objects. This reflected light can form images in human eyes or in a camera.

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The user specifies the location of the camera, light sources, and objects as well as the surface texture properties of objects, their interiors and environment. POV-Ray scenes are created in a special text language called a “scene description language (SDL)”.

POV-Ray can be used for animation too. Computer animation is the process of drawing objects on a computer screen, that then appearto move around the screen. It can be done displaying a series of stationary scenes with very short time between two scenes.

2. METHOD

The production of a 3D images has mainly two stages; writing and debugging source files and rendering. One has to choose the positions to locate the required objects, light source to illuminate the scene and appropriate camera position to capture, more technically called render,the scene. POV-Ray uses a simple Cartesian coordinate (Fig 1) system making easy to identify the suitable location.

Figure 1. Pov-ray coordinate system (+Z axis into the computer screen)

There are simple Pov-Ray SDL codes to generate almost all geometrical objects such as, box, sphere, and cylinder etc. The object “sphere” is the most appropriate object to represents the atoms while “cylinders’ to represent the atomic link.For the creation of scenes and animation described in this paper, exact coordinates of the object locations were simply calculated considering the dimension of the objects. Positioning light source to illuminate the scene, camera was located to get the suitable view. As an example following codes capture the scene, locating the camera at <20, 20, 10> looking at origin, <0,0,0>.

camera {

location <20,20,10>

look_at <0,0,0>}

Animations were created generating series of scenes, called frames, looking at the scene from various angles. Movie maker software such as Windows Film Maker, VirtualDub etc.can be used to play the frames continuously to make animation. Animation can be created as either animated jip or as AVI movie.A basic illustration of the process is shown below (Figure 3).

Figure 3. Schematic Diagram of Software used to Create Animations

3. SAMPLE CREATIONS

The first example portrays the hexagonal close packing (HCP) arrangement of spheres in the space (Figure 4.a). Hexagonal and cubic close packing arrangement (CCP)are explained to the student with the help of static plane diagrams. Many students are failed to understand these arrangements clearly. Even if they are able to explain the nature of alternative layering of the two arrangements, HCP and CCP, few students understand the nature of the voids available in such arrangement. This is valid for any average student, but of cause there may students who can understand those arrangements without any visual aid. The visual are made not for the aforementioned few students but for the majority to strengthen the understanding.

These particular animations have been chosen not just because of their curricular interest, but also to highlight some of the features of the POV-Ray rendering package. The first example portrays the hexagonal close packing arrangement (figure 1). As the arrangement is slowly rotates about the vertical axis which passes through the central sphere axis shown, the viewer can interactively explore the symmetry and geometric details for these configurations.

(a)(b)

Figure 4. Side view of HCP arrangement (b) Top view CCP arrangement

Visuals below (Figure 5) illustrate, Body Centered Cubic unit cell (a), and diamond type structure (c)and NaCl structure respectively. These creations are also possible to view from different angles, facilitating to learner to explore the structures.

1. (b)(c)

Figure 5: (a) Body Centered Cubic unit cell (b) diamond type structure (c) NaCl structure respectively.

Figure 6 shows an interstitial atom which is at an octahedral site, scenes were generated from different visual angles.

Figure 6 : An interstitial atom which is at an octahedral site

Author has introduced these animations for university undergraduate’s and received positive feedback. Introducing the animations for smartphone users have many advantages than using them only in computers (8). Student can use them freely, anytime any place with their own desire rather using computers.

4. CONCUSION

Since 3D visual aid transcends the limitations of static diagrams, it is promising tool to strengthen the understanding of various crystal structures. The animation examples that have been created in this work demonstrate that it is possible to create high quality 3-D animations using open source POV-Ray. POV-Ray visualization provides free access to sophisticated 3-D graphics rendering that could cost thousands of rupees commercially. It is worth explore the potential of Pov–Ray to simulate other complex concepts in physics to make the process of learning more independent and , student oriented. It has been confirmed that there is no any technical incompatibilities embedding these creation on smartphones. The evolution of the modern technology has to be integrated to physics teaching and make learning process more attractive.

5. REFERENCES

1. Muller,D.A, Designing Effective Multimedia for Physics Education (2008), Ph. D thesis
2. Michael R. Gallis, Ping Wang, Proceedings of the 2004 American Society for Engineering Education Annual Conference & Exposition, American Society for Engineering
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5. Park, O. C., & Gittelman, S. S. (1992). Selective use of animation and feedback in computer-based instruction. Educational Technology, Research, and Development, 40 (4), 27-38.
6. Park, O. (1998). Visual Displays and Contextual Presentations in Computer Based Instruction. Educational Technology Research & Development, 46 (3), pp. 18-32.
7. Woodcock, B Middleton, B and Nortcliffe,AConsidering the Smartphone Learner: an investigation into student interest in the use of personal technology to enhance their learning, Student Engagement and Experience,, Journal Volume 1, Issue 1 (on line journal)
8. JISC,Multimedia learning with mobile phones. Innovative Practices with E-learning. Case Studies: Anytime, Any Place Learning. [Online] Online at: http://www.jisc.ac.uk/uploaded_documents/southampton.pdf
9. Coca, D,M and Slisko, J. Software Socrative and Smartphones as Tools For Implementation of Basic Processes of Active Physics Learning in Classroom: An Initial Feasibility Study With Prospective Teachers, European J of Physics Education,Vol.4,Issue,2,2013

10. Wikipedia,http://en.wikipedia.org/wiki/Pov_ray