shadow casting
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2022 ◽  
Author(s):  
Rifqi Irzuan Abdul Jalal ◽  
Md Amin Md Nor ◽  
Hasan Muhamad Abid Hasan ◽  
Mohd Moktar Masban ◽  
Mohd Zaki Bahrom ◽  
...  

2021 ◽  
Author(s):  
xiaojiang li ◽  
Guoqing Wang

Abstract The sky view factor (SVF) that represents the fraction of visible sky on a hemisphere or the percentage of radiation reaching the planar ground in the entire hemisphere’s input radiation is an important parameter for urban climate studies. However, the estimation of a continuous SVF map is very time-consuming, which limits the applications of SVF to small geographical areas. This study proposed to use graphics processing unit (GPU) parallel computing to accelerate the computing of SVF in the city of Philadelphia, Pennsylvania, USA. This study implemented and compared both the GPU-accelerated version and regular CPU version of two major methods for estimating continuous SVF maps, ray tracing-based algorithm and shadow casting-based algorithm based on the high-resolution building height model. Results show that the GPU-accelerated algorithms can reduce the time consumption dramatically and estimate the SVF map for the city of Philadelphia in less than 20 minutes on a personal computer with one NVIDIA GPU. The ray tracing-based algorithm has a much more efficiency increase than the shadow casting-based algorithm on GPU. The proposed method makes it possible to generate large-scale continuous SVF maps using regular personal computers with GPU. The proposed GPU-accelerated SVF estimation methods would benefit urban climate studies.


2020 ◽  
pp. 147807712095754
Author(s):  
Tomohiro Fukuda ◽  
Marcos Novak ◽  
Hiroyuki Fujii ◽  
Yoann Pencreach

Virtual reality (VR) has been proposed for various purposes such as design studies, presentation, simulation and communication in the field of computer-aided architectural design. This paper explores new roles for VR; in particular, we propose rendering methods that consist of post-processing rendering, segmentation rendering and shadow-casting rendering for more-versatile approaches in the use of data. We focus on the creation of a dataset of annotated images, composed of paired foreground-background and semantic-relevant images, in addition to traditional immersive rendering for training deep learning neural networks and analysing landscapes. We also develop a camera velocity rendering method using a customised segmentation rendering technique that calculates the linear and angular velocities of the virtual camera within the VR space at each frame and overlays a colour on the screen according to the velocity value. Using this velocity information, developers of VR applications can improve the animation path within the VR space and prevent VR sickness. We successfully applied the developed methods to urban design and a design project for a building complex. In conclusion, the proposed method was evaluated to be both feasible and effective.


2020 ◽  
Vol 10 (15) ◽  
pp. 5361
Author(s):  
Nabil Stendardo ◽  
Gilles Desthieux ◽  
Nabil Abdennadher ◽  
Peter Gallinelli

In the context of encouraging the development of renewable energy, this paper deals with the description of a software solution for mapping out solar potential in a large scale and in high resolution. We leverage the performance provided by Graphics Processing Units (GPUs) to accelerate shadow casting procedures (used both for direct sunlight exposure and the sky view factor), as well as use off-the-shelf components to compute an average weather pattern for a given area. Application of the approach is presented in the context of the solar cadaster of Greater Geneva (2000 km2). The results show that doing the analysis on a square tile of 3.4 km at a resolution of 0.5 m takes up to two hours, which is better than what we were achieving with the previous work. This shows that GPU-based calculations are highly competitive in the field of solar potential modeling.


2020 ◽  
Vol 10 (10) ◽  
pp. 3533 ◽  
Author(s):  
Sebastian Romuli ◽  
Steffen Schock ◽  
Marius Kounbèsiounè Somda ◽  
Joachim Müller

The drying performance of paddy rice using an inflatable solar dryer (ISD), or also known as GrainPro® Solar Bubble Dryer™, was evaluated and compared to conventional sun drying in Burkina Faso. Drying time was around eight hours. Thermal imaging was conducted to observe temperature distribution in the ISD during drying and mixing. Shadow casting was observed in the ISD due to the round shape of the black plastic film, which reduced the temperature of the paddy rice to about 10 °C. The temperature inside the ISD was up to 13 °C higher than the ambient temperature, whereas the temperature of paddy rice on the top layer was about 5 °C higher than on the bottom. The final moisture content of paddy rice dried in the ISD and under the sun was not considerably different. Under certain circumstances, impurities in paddy rice dried in the ISD could be substantially lower than for sun drying. The aflatoxin level of paddy rice was under the maximum limit of the EU regulation. Drying paddy rice seemed to be effective to remove aflatoxin type AFG2 content. Further adaptation of the ISD design for drying operations on rough surfaces and sandy soils is suggested.


2019 ◽  
Vol 44 (15) ◽  
pp. 3897
Author(s):  
Jorge Tordera Mora ◽  
Xiaohua Feng ◽  
Liang Gao
Keyword(s):  

2017 ◽  
Vol 4 (3) ◽  
pp. 5-37
Author(s):  
G. Terence Meaden

A new survey of Drombeg Stone Circle and accurate analysis of shadow effects beginning at particular sunrises of the calendar year has led to a breakthrough in the understanding of lithic symbolism and the intentions behind the construction of this and other Irish monuments including Knowth and Newgrange that also have astronomical alignments. At Drombeg specific standing stones play critical roles at sunrise for all eight of the festival dates as known traditionally and historically for agricultural communities and as now inferred for prehistoric times following the present observation-based analysis.Crucial for Drombeg in the summer half of the year is the positioning of a tall straight-sided portal stone such that its shadow at midsummer sunrise encounters an engraving on the recumbent stone diametrically opposite. During subsequent minutes the shadow moves away allowing the light of the sun to fall on the carved symbol. It is the same for sunrises at Beltane (May Day), Lughnasadh (Lammas), and the equinoxes when shadows from other perimeter stones achieve the same coupling with the same image, each time soon replaced by sunlight. For the winter half of the year which includes dates for Samhain, the winter solstice and Imbolc, the target stone for shadow reception at sunrise is a huge lozenge-shaped megalith, artificially trimmed. Moreover, for 22 March and 21 September there is notable dramatic action by shadow and light between a precisely positioned narrow pillar stone and the lozenge stone.As a result, at sunrise at Drombeg eight calendrical shadow events have been witnessed and photographed. This attests to the precision of Neolithic planning that determined the stone positions, and demonstrates the antiquity of the calendar dates for these traditional agricultural festivals. Discussion is held as to what the concept of shadow casting between shaped or engraved stones at the time of sunrise may have meant in terms of lithic symbolism for the planners and builders. This leads to a possible explanation in terms of the ancient worldview known as the hieros gamos or the Marriage of the Gods between Sky and Earth.


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