Application of virtual Reality in Landscape Architecture planning and Design and Hierarchical detail optimization - Dr. Xuesong Tian
Abstract: In order to enhance the intuitiveness and authenticity of space vision of designers, in order to better carry out computer-aided design of landscape scene, the digital design application of landscape planning through virtual reality technology is proposed. Firstly, the VRML tool used in virtual reality technology aided design is introduced. Then, the LOD level detail algorithm is used to draw real-time terrain, so as to reduce the number of triangular cracks. Finally, I combined SketchUp and Auto CAD to complete a concrete virtual reality planning demonstration of landscape architecture. The demonstration results show that users can freely observe and experience the virtual garden environment through man-machine interaction.
Keywords: Virtual reality technology; Landscape architecture; Landscape planning; VRML; CAD; SketchUp
1 the introduction
With the continuous progress and development of China's society, the national economy and the quality of life of the public have been greatly improved. People gradually pay attention to environmental protection and the construction of landscape architecture . With the continuous innovation of computer application technology, the traditional landscape planning and design which need to make drawings has begun to fail to meet the needs of The Times. The traditional drawing of design schemes begins to make use of VR (virtual reality) in the space environment and gradually becomes a popular application direction [2⁃3]. The computer-aided technologies used in landscape architecture planning and design can be mainly divided into Auto CAD, Arc GIS and VR . Through the above technologies and software, designers can more quickly and conveniently carry out landscape planning and design work, especially VR technology.
Literature  takes the landscape of the Research center of Beijing Forestry University as an example to carry out the digital practice of landscape architecture planning and design. Literature  takes THE AR system in VR technology as the technical basis and develops the virtual platform APP of landscape design based on the operating environment of iPad. The interactive interface of THE APP is simple and practical, realizing the functions of material acquisition and editing, insertion of landscape elements, real-time acquisition of line grid and so on.
In order to promote the organic combination of virtual reality technology and landscape planning and design, so as to enhance the visual and authenticity of designers in space, so as to better carry out computer-aided landscape scene design, this paper puts forward the digital design application of landscape planning through virtual reality technology. Firstly, the advantages of virtual reality technology in landscape architecture planning and design are briefly analyzed. Secondly, the VRML (Virtual Reality Modeling Language) tool used in the aided design of Virtual Reality technology is introduced. Finally, starting from the actual case, combined with CAD drawing and 3D character modeling, the overall structure of the project, the specific design process and programming methods are given. Finally, SketchUp and virtual reality software are used to build a virtual reality scene of landscape architecture. Through human-computer interaction, users can freely observe and experience the virtual landscape environment, which effectively promotes the innovation and development of landscape architecture planning and design.
2. Landscape architecture planning and design based on VR assistive technology
This paper uses VRML and text information to describe 3d scenes. The 3d scene is transmitted on the Internet and interpreted by the BROWSER of VRML on the local machine. The standard specification of interpretation is VRML specification [8⁃9]. The ACCESS mode of VRML is based on THE C/S mode, in which the server provides VRML files. VRML provides 6+1 degrees of freedom, namely movement and rotation in three directions, as well as hyperlinks to other 3D Spaces. The general framework for VRML applications is shown in Figure 1.
Figure 1. General framework for VRML applications
The overall structure of the system of "Landscape planning and Design of an Urban Landscape architecture" is shown in Figure 2, which is mainly divided into CAD drawing, 3D model building, scene integration and system interaction.
Figure 2 overall structure of the system
3 Case Analysis
3.1 Hardware and Software Platform Parameters
This paper takes "a city landscape planning and design" as a practical case to carry out specific experiments. The hardware configuration of the experimental PC host is: Intel Core I5 ⁃8500 quad-core CPU, the main frequency is 3.0GHz; 8 gb of memory; Nvidia GTX 970 graphics card (4 GB video memory); 500 GB hard disk. The software platform includes: Auto CAD 3d drawing software; SketchUp 3D modeling software; Adobe photoshoppsCS6 2d mapping software.
3.2 Realization of key 3D objects in the project
In the project task of "Landscape Planning and Design of an Urban Landscape Garden", the main three-dimensional objects of the landscape scene are slope grassland, rockery and wide area. The optimization performance curve of VR scene is shown in Figure 3. It can be seen that with the increase of the number of grids, the number of triangular cracks gradually decreases, thus effectively optimizing the visual display effect. We selected Indexed Face Set node to draw the graphs of grassland and wide areas. After calculating and mapping the points of all coordinate point axes, we got the effect of slope and surrounding grassland as shown in Figure 4.
Figure 3 Optimization performance curve of VR scenarios
Figure 4 Slope and surrounding grassland
For the complicated rockery, Elevation Grid nodes are adopted to achieve the final effect, as shown in Figure 5, including the wide area around the rockery.
FIG. 5 Rockery and surrounding floor area
The final operation results show that the landscape architecture design system based on VR technology has good real-time performance and fast operation speed.
This paper proposes to realize the digital design application of landscape planning through virtual reality technology, so as to carry on the computer aided design of landscape scene better. Based on the actual case, combined with CAD drawing and 3D character modeling, the overall structure, specific design process and programming method of the project are given. Finally, SketchUp and virtual reality software are used to build a virtual reality scene of landscape architecture. Through human-computer interaction, users can freely observe and experience the virtual landscape environment, which effectively promotes the innovation and development of landscape architecture planning and design, and enhances the intuitive and real experience sense of designers in landscape planning and design.
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