Assessing the impact of geometric design intent annotations on parametric model alteration activities

The effective representation and communication of design intent plays a crucial role in CAD model alteration activities. In history-based parametric modeling systems, design intent information is usually expressed implicitly within the model. However, there is evidence that suggests that an explicit representation can increase productivity and quality and facilitate the transferring of design knowledge throughout the different stages of the product lifecycle. In this paper, we assess the effectiveness of 3D annotations as mechanisms for explicit design intent representation and examine their impact in model alteration processes that require a direct interaction with the model s geometry. We present the results of a series of studies aimed at measuring user performance and model quality in two scenarios. First, we hypothesized that annotations are valuable tools to provide design information when inadequate modeling assumptions can be made by designers. Second, we evaluated annotations as tools to communicate design decisions when multiple options are available. In both cases, results show statistically significant benefits of annotated models, suggesting the use of this technique as a valuable approach to improve design intent communication.This work was supported by the Spanish Ministry of Economy and Competitiveness and the FEDER Funds, through the ANNOTA project (Ref. TIN2013-46036-C3-1-R).Camba, JD.; Contero, M. (2015). Assessing the impact of geometric design intent annotations on parametric model alteration activities. Computers in Industry. 71:35-45. https://doi.org/10.1016/j.compind.2015.03.006S35457

Parametric CAD modeling: An analysis of strategies for design reusability

CAD model quality in parametric design scenarios largely determines the level of flexibility and adaptability of a 3D model (how easy it is to alter the geometry) as well as its reusability (the ability to use existing geometry in other contexts and applications). In the context of mechanical CAD systems, the nature of the feature-based parametric modeling paradigm, which is based on parent-child interdependencies between features, allows a wide selection of approaches for creating a specific model. Despite the virtually unlimited range of possible strategies for modeling a part, only a small number of them can guarantee an appropriate internal structure which results in a truly reusable CAD model. In this paper, we present an analysis of formal CAD modeling strategies and best practices for history-based parametric design: Delphi's horizontal modeling, explicit reference modeling, and resilient modeling. Aspects considered in our study include the rationale to avoid the creation of unnecessary feature interdependencies, the sequence and selection criteria for those features, and the effects of parent/child relations on model alteration. We provide a comparative evaluation of these strategies in the form of a series of experiments using three industrial CAD models with different levels of complexity. We analyze the internal structure of the models and compare their robustness and flexibility when the geometry is modified. The results reveal significant advantages of formal modeling methodologies, particularly resilient techniques, over non-structured approaches as well as the unexpected problems of the horizontal strategy in numerous modeling situations. (C)2016 Elsevier Ltd. All rights reserved.Camba, JD.; Contero, M.; Company, P. (2016). Parametric CAD modeling: An analysis of strategies for design reusability. Computer-Aided Design. 74:18-31. doi:10.1016/j.cad.2016.01.003S18317

Interactive Experiences in Public Spaces: A Novel Floor Display System Based on Luminous Modular Units

We describe the design of an interactive concrete floor display for public spaces and discuss its implementation and areas of application. The primary purpose of our system is to provide new forms of collaborative interaction in long-term installations in both indoor and outdoor spaces. Our design is an expandable system of interconnected tiles, which control an array of RGB Light-Emitting Diodes (LEDs) based on user input. The LEDs are built into the tiles and arranged in a manner that simulates pixels on a computer screen, providing a natural visualization mechanism. Each tile acts as an independent node in a network, where motion sensors trigger specific actions and provide interactivity to the surface. A series of applications are illustrated, including promotional advertising and interactive games. The system was installed and evaluated on a university campus for four weeks where hundreds of visitors successfully interacted with the floor

Assessment of parametric assembly models based on CAD quality dimensions

[EN] An approach to convey CAD quality-oriented strategies to beginning users to create bottom-up assemblies is described. The work builds on previous efforts in the area of single part history-based, feature-based parametric modeling evaluation by defining, testing, and validating a set of quality dimensions that can be applied to MCAD assembly assessment. The process of redefining and adapting dimension descriptors and achievement levels of parts rubrics to make them applicable to assemblies is addressed, then the results of two experimental studies designed to analyze the inter-rater reliability of this approach to assembly evaluation are reported. Results suggest the mechanism is reliable to provide an objective assessment of assembly models. Limitations for the formative selfevaluation of CAD assembly skills are also identified.This work was partially supported by the Spanish grant DPI2017-84526-R (MINECO/AEI/FEDER, UE), project CAL-MBE, Implementation and validation of a theoretical CAD quality model in a Model-Based Enterprise (MBE) context. , and the ANNOTA2 project funded by Universitat Politècnica de València.Otey, J.; Company, P.; Contero, M.; Camba, JD. (2019). Assessment of parametric assembly models based on CAD quality dimensions. Computer-Aided Design and Applications. 16(4):628-653. https://doi.org/10.14733/cadaps.2019.628-653S62865316

A quantitative analysis of parametric CAD model complexity and its relationship to perceived modeling complexity

Digital product data quality and reusability has been proven a critical aspect of the Model-Based Enterprise to enable the efficient design and redesign of products. The extent to which a history-based parametric CAD model can be edited or reused depends on the geometric complexity of the part and the procedure employed to build it. As a prerequisite for defining metrics that can quantify the quality of the modeling process, it is necessary to have CAD datasets that are sorted and ranked according to the complexity of the modeling process. In this paper, we examine the concept of perceived CAD modeling complexity, defined as the degree to which a parametric CAD model is perceived as difficult to create, use, and/or modify by expert CAD designers. We present a novel method to integrate pair-wise comparisons of CAD modeling complexity made by experts into a single metric that can be used as ground truth. Next, we discuss a comprehensive study of quantitative metrics which are derived primarily from the geometric characteristics of the models and the graph structure that represents the parent/child relationships between features. Our results show that the perceived CAD modeling complexity metric derived from experts’ assessment correlates particularly strongly with graph-based metrics. The Spearman coefficients for five of these metrics suggest that they can be effectively used to study the parameters that influence the reusability of models and as a basis to implement effective personalized learning strategies in online CAD training scenarios

From voice to knowledge: A proposal for a voice annotation system to support collaborative engineering design processes

This paper describes a novel voice interaction mechanism for capturing and managing design knowledge within a collaborative Computer-Aided Design (CAD) environment. We present a software module for speech recognition that integrates with a CAD application to allow the automatic creation of textual annotations in a 3D model directly from voice data. Audio is transcribed automatically, resulting in a textual note that is searchable and available to other users via a Product Data Management (PDM) system, providing an intuitive mechanism to document modeling processes and design knowledge. The system consists of three functional blocks: (1) audio recording, (2) speech recognition, and (3) query management against a cloud-based service. In this paper, we justify the need for our system from a human-computer interaction standpoint and discuss the rationale of its design and implementation in the context of collaborative design communication. Finally, we discuss some application spaces that demonstrate the capability of voice annotations for capturing knowledge

CAD training for digital product quality: a formative approach with computer-based adaptable resources for self-assessment

[EN] As the engineering and manufacturing sectors transform their processes into those of a digital enterprise, future designers and engineers must be trained to guarantee the quality of the digital models that are created and consumed throughout the product's lifecycle. Formative training approaches, particularly those based on online rubrics, have been proven highly effective for improving CAD modeling practices and the quality of the corresponding outcomes. However, an effective use of formative rubrics to improve performance must consider two main factors: a proper understanding of the rubric and an accurate self-assessment. In this paper we develop these factors by proposing CAD training based on self-assessment through online formative rubrics enriched with adaptable resources. We analyzed self-assessment data, such as time spent, scoring differences between trainee and instructor or use of the adaptable resources, of fourteen different CAD exams. Results show that resources are more effective when used without any incentives. The comparison of assessments by quality criterion can facilitate the identification of issues that may remain unclear to trainees during the learning process. These results can guide the definition of new strategies for self-training processes and tools, which can contribute to the higher-quality outcomes and CAD practices that are required in model-bases engineering environments.Agost, M.; Company, P.; Contero, M.; Camba, JD. (2022). CAD training for digital product quality: a formative approach with computer-based adaptable resources for self-assessment. International Journal of Technology and Design Education. 32(2):1393-1411. https://doi.org/10.1007/s10798-020-09651-51393141132

On the integration of model-based feature information in Product Lifecycle Management systems

[EN] As CAD models continue to become more critical information sources in the product's lifecycle, it is necessary to develop efficient mechanisms to store, retrieve, and manage larger volumes of increasingly complex data. Because of their unique characteristics, 3D annotations can be used to embed design and manufacturing information directly into a CAD model, which makes models effective vehicles to describe aspects of the geometry or provide additional information that can be connected to a particular geometric element. However, access to this information is often limited, difficult, and even unavailable to external applications. As model complexity and volume of information continue to increase, new and more powerful methods to interrogate these annotations are needed. In this paper, we demonstrate how 3D annotations can be effectively structured and integrated into a Product Lifecycle Management (PLM) system to provide a cohesive view of product-related information in a design environment. We present a strategy to organize and manage annotation information which is stored internally in a CAD model, and make it fully available through the PLM. Our method involves a dual representation of 3D annotations with enhanced data structures that provides shared and easy access to the information. We describe the architecture of a system which includes a software component for the CAD environment and a module that integrates with the PLM server. We validate our approach through a software prototype that uses a parametric modeling application and two commercial PLM packages with distinct data models.This work was supported by the Spanish Ministry of Economy and Competitiveness and the FEDER Funds, through the ANNOTA project (Ref. TIN2013-46036-C3-1-R).Camba, J.; Contero, M.; Company, P.; Pérez Lopez, DC. (2017). On the integration of model-based feature information in Product Lifecycle Management systems. International Journal of Information Management. 37(6):611-621. https://doi.org/10.1016/j.ijinfomgt.2017.06.002S61162137

On the effects of the fix geometric constraint in 2D profiles on the reusability of parametric 3D CAD models

[EN] In order to be reusable, history-based feature-based parametric CAD models must reliably allow for modifications while maintaining their original design intent. In this paper, we demonstrate that relations that fix the location of geometric entities relative to the reference system produce inflexible profiles that reduce model reusability. We present the results of an experiment where novice students and expert CAD users performed a series of modifications in different versions of the same 2D profile, each defined with an increasingly higher number of fix geometric constraints. Results show that the amount of fix constraints in a 2D profile correlates with the time required to complete reusability tasks, i.e., the higher the number of fix constraints in a 2D profile, the less flexible and adaptable the profile becomes to changes. In addition, a pilot software tool to automatically track this type of constraints was developed and tested. Results suggest that the detection of fix constraint overuse may result in a new metric to assess poor quality models with low reusability. The tool provides immediate feedback for preventing high semantic level quality errors, and assistance to CAD users. Finally, suggestions are introduced on how to convert fix constraints in 2D profiles into a negative metric of 3D model quality.The authors would like to thank Raquel Plumed for her support in the statistical analysis. This work has been partially funded by Grant UJI-A02017-15 (Universitat Jaume I) and DPI201784526-R (MINECO/AEI/FEDER, UE), project CAL-MBE. The authors also wish to thank the editor and reviewers for their valuable comments and suggestions that helped us improve the quality of the paper.González-Lluch, C.; Company, P.; Contero, M.; Pérez Lopez, DC.; Camba, JD. (2019). On the effects of the fix geometric constraint in 2D profiles on the reusability of parametric 3D CAD models. 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Revisiting the design intent concept in the context of mechanical CAD education

[EN] Design intent is generally understood simply as a CAD model¿s anticipated behavior when altered. However, this representation provides a simplified view of the model¿s construction and purpose, which may hinder its general understanding and future reusability. Our vision is that design intent communication may be improved by recognizing the multifaceted nature of design intent, and by instructing users to convey each facet of design intent through the better-fitted CAD resource. This paper reviews the current understanding of design intent and its relationship to design rationale and builds on the idea that communication of design intent conveyed via CAD models can be satisfied at three levels provided that specialized instruction is used to instruct users in selection of the most suitable level for each intent.Otey, J.; Company, P.; Contero, M.; Camba, J. (2018). Revisiting the design intent concept in the context of mechanical CAD education. Computer-Aided Design and Applications. 15(1):47-60. https://doi.org/10.1080/16864360.2017.1353733S476015