scholarly journals Quantifying asymmetry in non-symmetrical morphologies, with an example from Cetacea

2021 ◽  
Author(s):  
Ellen J Coombs ◽  
Ryan N Felice
Keyword(s):  
Three Dimensional ◽  
Morphometric Data ◽  
Step Method ◽  
Crucial Step ◽  
Asymmetric Structures ◽  
3D Surface ◽  
Morphometric Analyses ◽  
Landmark Data ◽  
Dimensional Measurements

Three-dimensional measurements of morphology are key to gaining an understanding of a species' biology and to answering subsequent questions regarding the processes of ecology (or palaeoecology), function, and evolution. However, the collection of morphometric data is often focused on methods designed to produce data on bilaterally symmetric morphologies which may mischaracterise asymmetric structures. Using 3D landmark and curve data on 3D surface meshes of specimens, we present a method for first quantifying the level of asymmetry in a specimen and second, accurately capturing the morphology of asymmetric specimens for further geometric analyses. We provide an example of the process from initial landmark placement, including details on how to place landmarks to quantify the level of asymmetry, and then on how to use this information to accurately capture the morphology of asymmetric morphologies or structures. We use toothed whales (odontocetes) as a case study and include examples of the consequences of mirroring landmarks and curves, a method commonly used in bilaterally symmetrical specimens, on asymmetric specimens. We conclude by presenting a step-by-step method to collecting 3D landmark data on asymmetric specimens. Additionally, we provide code for placing landmarks and curves on asymmetric specimens in a manner designed to both save time and ultimately accurately quantify morphology. This method can be used as a first crucial step in morphometric analyses of any biological specimens by assessing levels of asymmetry and then if required, accurately quantifying this asymmetry. The latter not only saves the researcher time, but also accurately represents the morphology of asymmetric structures.

scholarly journals Considerations for post-processing parameters in mixed-method 3-D analyses: A Mesolithic mandibular case study

2021 ◽  
Author(s):  
Robert Z. Selden ◽  
lauren butaric ◽  
Kersten Bergstrom ◽  
Dennis Van Gerven
Keyword(s):  
Three Dimensional ◽  
Processing Parameters ◽  
Surface Model ◽  
Digital Repositories ◽  
Computed Tomographic ◽  
Archaeological Data ◽  
Morphometric Analyses ◽  
Smoothing Parameters ◽  
Ct Data

The production of three-dimensional (3-D) digital meshes of surface and computed tomographic (CT) data has become widespread in morphometric analyses of anthropological and archaeological data. Given that processing methods are not standardised, this leaves questions regarding the comparability of processed and digitally curated 3-D datasets. The goal of this study was to identify those processing parameters that result in the most consistent fit between CT-derived meshes and a 3-D surface model of the same human mandible. Eight meshes, each using unique thresholding and smoothing parameters, were compared to assess whole-object deviations, deviations along curves, and deviations between specific anatomical features on the surface model when compared with the CT scans using a suite of \textit{comparison points}. Based on calculated gap distances, the mesh thresholded at "0" with an applied smoothing technique was found to deviate least from the surface model; although, it is not the most biologically accurate. Results have implications for aggregated studies that employ multi-modal 3-D datasets, and caution is recommended for studies that enlist 3-D data from websites and digital repositories, particularly if processing parameters are unknown or derived for studies with different research foci.

scholarly journals 3D Sketching and Flexible Input for Surface Design: A Case Study

2014 ◽  
Vol 5 (3) ◽  
pp. 1
Author(s):  
Anamary Leal ◽  
Doug A. Bowman
Keyword(s):  
Three Dimensional ◽  
Physical World ◽  
Design System ◽  
3D Interaction ◽  
Surface Design ◽  
Domain Experts ◽  
3D Surface ◽  
Modeling Software ◽  
Interactive Surface

Designing three-dimensional (3D) surfaces is difficult in both the physical world and in 3D modeling software, requiring background knowledge and skill. The goal of this work is to make 3D surface design easier and more accessible through natural and tangible 3D interaction, taking advantage of users' proprioceptive senses to help them understand 3D position, orientation, size, and shape. We hypothesize that flexible input based on fabric may be suitable for 3D surface design, because it can be molded and folded into a desired shape, and because it can be used as a dynamic flexible brush for 3D sketching. Fabric3D, an interactive surface design system based on 3D sketching with flexible input, explored this hypothesis. Through a longitudinal five-part study in which three domain experts used Fabric3D, we gained insight into the use of flexible input and 3D sketching for surface design in various domains.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

scholarly journals Generative Models for Relief Perspective Architectures

2021 ◽  
Author(s):  
Leonardo Baglioni ◽  
Federico Fallavollita
Keyword(s):  
Research Methodology ◽  
Affine Space ◽  
Three Dimensional ◽  
Generative Models ◽  
Linear Perspective ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Present Essay ◽  
Santa Maria

AbstractThe present essay investigates the potential of generative representation applied to the study of relief perspective architectures realized in Italy between the sixteenth and seventeenth centuries. In arts, and architecture in particular, relief perspective is a three-dimensional structure able to create the illusion of great depths in small spaces. A method of investigation applied to the case study of the Avila Chapel in Santa Maria in Trastevere in Rome (Antonio Gherardi 1678) is proposed. The research methodology can be extended to other cases and is based on the use of a Relief Perspective Camera, which can create both a linear perspective and a relief perspective. Experimenting mechanically and automatically the perspective transformations from the affine space to the illusory space and vice versa has allowed us to see the case study in a different light.

Decolonising a landscape architecture studio: Spatial modelling of student narratives

2021 ◽  
Vol 1 (1) ◽  
pp. 39-47
Author(s):  
Christine Price
Keyword(s):  
Spatial Model ◽  
Meaning Making ◽  
Three Dimensional ◽  
Spatial Modelling ◽  
First Year ◽  
Spatial Form ◽  
Public Park ◽  
New Meanings ◽  
Global North

This paper problematises the dominance of global north perspectives in landscape architectural education, in South Africa where there are urgent calls to decolonise education and make visible indigenous and vernacular meaning-making practices. In grappling with these concerns, this research finds resonance with a multimodal social semiotic approach that acknowledges the interest, agency and resourcefulness of students as meaning-makers in both accessing and challenging dominant educational discourses. This research involves a case study of a design project in a first-year landscape architectural studio. The project requires students to choose a narrative and to represent it as a spatial model: a scaled, 3D maquette of a spatial experience that could be installed in a public park. This practitioner reflection closely analyses the spatial model of one student, Malibongwe, focusing on his interest in meaning-making; the innovative meaning-making practices and diverse resources he draws on; and his expression of spatial signifiers of the Black experiences portrayed in his narrative. This reflection shows how Malibongwe’s narrative is not only reproduced in the spatial model, it is remade: the transformation of resources into three-dimensional spatial form results in new understandings and the production of new meanings.

scholarly journals Data-Driven Intelligent 3D Surface Measurement in Smart Manufacturing: Review and Outlook

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Yuhang Yang ◽  
Zhiqiao Dong ◽  
Yuquan Meng ◽  
Chenhui Shao
Keyword(s):  
High Resolution ◽  
High Performance ◽  
Sampling Design ◽  
Three Dimensional ◽  
Measurement Data ◽  
Data Driven ◽  
Surface Measurement ◽  
Smart Manufacturing ◽  
Future Research ◽  
3D Surface

High-fidelity characterization and effective monitoring of spatial and spatiotemporal processes are crucial for high-performance quality control of many manufacturing processes and systems in the era of smart manufacturing. Although the recent development in measurement technologies has made it possible to acquire high-resolution three-dimensional (3D) surface measurement data, it is generally expensive and time-consuming to use such technologies in real-world production settings. Data-driven approaches that stem from statistics and machine learning can potentially enable intelligent, cost-effective surface measurement and thus allow manufacturers to use high-resolution surface data for better decision-making without introducing substantial production cost induced by data acquisition. Among these methods, spatial and spatiotemporal interpolation techniques can draw inferences about unmeasured locations on a surface using the measurement of other locations, thus decreasing the measurement cost and time. However, interpolation methods are very sensitive to the availability of measurement data, and their performances largely depend on the measurement scheme or the sampling design, i.e., how to allocate measurement efforts. As such, sampling design is considered to be another important field that enables intelligent surface measurement. This paper reviews and summarizes the state-of-the-art research in interpolation and sampling design for surface measurement in varied manufacturing applications. Research gaps and future research directions are also identified and can serve as a fundamental guideline to industrial practitioners and researchers for future studies in these areas.

scholarly journals Protocol for preparation of heterogeneous biological samples for 3D electron microscopy: a case study for insects

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexey A. Polilov ◽  
Anastasia A. Makarova ◽  
Song Pang ◽  
C. Shan Xu ◽  
Harald Hess
Keyword(s):  
Electron Microscopy ◽  
Biological Samples ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Entire Volume ◽  
Simple Protocol ◽  
3D Electron Microscopy ◽  
3D Em

AbstractModern morphological and structural studies are coming to a new level by incorporating the latest methods of three-dimensional electron microscopy (3D-EM). One of the key problems for the wide usage of these methods is posed by difficulties with sample preparation, since the methods work poorly with heterogeneous (consisting of tissues different in structure and in chemical composition) samples and require expensive equipment and usually much time. We have developed a simple protocol allows preparing heterogeneous biological samples suitable for 3D-EM in a laboratory that has a standard supply of equipment and reagents for electron microscopy. This protocol, combined with focused ion-beam scanning electron microscopy, makes it possible to study 3D ultrastructure of complex biological samples, e.g., whole insect heads, over their entire volume at the cellular and subcellular levels. The protocol provides new opportunities for many areas of study, including connectomics.

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