A Computationally Cheap Trick to Determine Shadow in a Voxel Model

Gorte, B.G.H.; Zhou, K.; Sande, C. J. van der; Valk, C.F. de

doi:10.5194/isprs-annals-iv-4-67-2018

Cited by 7 publications

(5 citation statements)

References 2 publications

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“…The procedure starts with the surface voxelization of the input triangular mesh triangles and classifies the voxels into two groups: α and β. Voxelization is a well-known technique in computer graphics for fast calculation (Aleksandrov et al, 2021) such as ray tracing (Amanatides and Woo, 1987), approximation of surfaces and solids (Schwarz and Seidel, 2010), shadow rendering (Gorte et al, 2018) and visibility test (Aleksandrov et al, 2019). It can also be applied to 3D printing application.…”

Section: Prediction Of Optimal 3d Printingmentioning

confidence: 99%

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Prediction of optimal 3D printing orientation using vertically sparse voxelization and modified support structure tomography

Jung

Chee

Sul

2023

IJCST

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PurposeIncreasingly 3D printing is used for parts of garments or for making whole garments due to their flexibility and comfort and for functionalizing or enhancing the aesthetics of the final garment and hence adding value. Many of these applications rely on complex programming of the 3D printer and are usually provided by the vendor company. This paper introduces a simpler, easier platform for designing 3D-printed textiles, garments and other artifacts, by predicting the optimal orientation of the target objects to minimize the use of plastic filaments.Design/methodology/approachThe main idea is based on the shadow-casting analogy, which assumes that the volume of the support structure is similar to that of the shadow from virtual sunlight. The triangular elements of the target object are converted into 3D pixels with integer-based normal vectors and real-numbered coordinates via vertically sparse voxelization. The pixels are classified into several groups and their noise is suppressed using a specially designed noise-filtering algorithm called slot pairing. The final support structure volume information was rendered as a two-dimensional (2D) figure, similar to a medical X-ray image. Thus, the authors named their method modified support structure tomography.FindingsThe study algorithm showed an error range of no more than 1.6% with exact volumes and 6.8% with slicing software. Moreover, the calculation time is only several minutes for tens of thousands of mesh triangles. The algorithm was verified for several meshes, including the cone, sphere, Stanford bunny and human manikin.Originality/valueSimple hardware, such as a CPU, embedded system, Arduino or Raspberry Pi, can be used. This requires much less computational resources compared with the conventional g-code generation. Also, the global and local support structure is represented both quantitatively and graphically via tomographs.

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Section: Prediction Of Optimal 3d Printingmentioning

confidence: 99%

“…Voxelization is a well-known technique in computer graphics for fast calculation (Aleksandrov et al. , 2021) such as ray tracing (Amanatides and Woo, 1987), approximation of surfaces and solids (Schwarz and Seidel, 2010), shadow rendering (Gorte et al. , 2018) and visibility test (Aleksandrov et al.…”

Section: Previous Workmentioning

confidence: 99%

Prediction of optimal 3D printing orientation using vertically sparse voxelization and modified support structure tomography

Jung

Chee

Sul

2023

IJCST

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“…The main reason for this is to generalise the space optimally so the main characteristics of the environment are retained. With such representation, some of the computational operations can be reduced and the result is still accurate enough for our purpose (Gorte et al, 2018). This approach is also very useful for modelling objects with irregular shapes such as trees.…”

Section: Data Structurementioning

confidence: 99%

Voxel-Based Visibility Analysis for Safety Assessment of Urban Environments

Aleksandrov¹,

Zlatanova²,

Kimmel³

et al. 2019

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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<p><strong>Abstract.</strong> This paper presents the research and development of a volumetric 3D visibility analysis application to assess public space in regards to safety and security. While most of the academic literature on space visibility concentrates on developing viewsheds from a specific viewpoint, this work integrates dynamic scenarios and real-time calculation of space visibility. Voxel-based spatial representation is utilised as a base for the 3D visibility analysis. Different space configurations are tested illustrating the robustness and usefulness of the developed application. In order to measure and evaluate different safety zones, an innovative approach is tested according to which the number of times each voxel is observed is recorded and further classified into different zones. In this way, an accurate calculation of the observed space can be performed understanding which part of an area of interest is less or more observed. The research has shown great potential for first responders, researchers, architects and safety experts. The developed application can be used as a simulation tool to assess the safety of different urban environments and identify potentially vulnerable locations.</p>

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“…Voxels are commonly being investigated in many application domains including computer graphics (Amanatides & Woo, 1987), city modelling (Nießner et al, 2013), geology (Jørgensen et al, 2013), spatial analysis (Beckhaus et al, 2002), point clouds processing (Vo et al, 2015), machine learning (Poux & Billen, 2019), collision detections (Silver & Gagvani, 2000), shadow calculations (Gorte et al, 2018), visibility analysis (Aleksandrov et al, 2019), egress modelling , pedestrian navigation (Bernardus and so on. As we can see voxels are highly applicable and further investigations are required to better understand their characteristics and advantages.…”

Section: Introductionmentioning

confidence: 99%

Voxelisation and Voxel Management Options in Unity3d

Aleksandrov¹,

Zlatanova²,

Heslop

2022

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Voxels have been used in various application domains successfully for the last several decades. Their main advantage is the underlying discrete data structure allowing to reliably work with surrounding voxels all the time. In this paper, capabilities of the Unity game engine for voxels management and geometry voxelisation are assessed, where 4 native solutions and 7 open-source projects written for Unity are investigated. Although many voxel-based options exist in Unity, they only deal with one part related to voxels. Therefore, the available capabilities to voxelise, visualise, structure and export voxels are combined and extended with the goal of successfully processing large 3D models and geometries. Many voxel visualisation techniques are investigated including mesh, VFX, point clouds and SVO, which have distinctive benefits in various aspects. Possibilities to structure voxels for effective management in simulations and other tasks are shown. Also, it is enabled to export voxels as point clouds and to the Postgres database for further processing, spatial analysis and distribution. One of the main conclusions is the lack of support for state-of-the-art voxel data structures, where the presented platform can easily be extended to support any. This platform can be used by people who deal with 3D discrete data, require voxelising 3D data, visualise voxels in different ways and technologies, as well as manage more efficiently sparsely occupied voxels.

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A Computationally Cheap Trick to Determine Shadow in a Voxel Model

Cited by 7 publications

References 2 publications

Prediction of optimal 3D printing orientation using vertically sparse voxelization and modified support structure tomography

Prediction of optimal 3D printing orientation using vertically sparse voxelization and modified support structure tomography

Voxel-Based Visibility Analysis for Safety Assessment of Urban Environments

Voxelisation and Voxel Management Options in Unity3d

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