FEAsy: A Sketch-Based Interface Integrating Structural Analysis in Early Design

Abstract

The potential advantages of freehand sketches have been widely recognized and exploited in many fields especially in engineering design and analysis. This is mainly because the freehand sketches are an efficient and natural way for users to visually communicate ideas. However, due to a lack of fundamental techniques for understanding them, sketch-based interfaces have not yet evolved as the preferred computing platform over traditional menu-based tools. In this paper, we address the specific challenge of transforming informal and ambiguous freehand inputs to more formalized and structured representations. We present a domain-independent, multi-stroke, multi-primitive beautification method which detects and uses the spatial relationships implied in the sketches. Spatial relationships are represented as geometric constraints and satisfied by a geometric constraint solver. To demonstrate the utility of this technique and also to build a natural working environment for structural analysis in early design, we have developed FEAsy (acronym for Finite Element Analysis made easy) as shown in Fig. 1. This tool allows the users to transform, simulate and analyze their finite element models quickly and easily through freehand sketching, just as they would draw on paper. Further, we have also developed simple, domain specific rules-based algorithms for recognizing the commonly used symbols and for understanding the different contexts in finite element modeling. Finally, we illustrate the proposed approach with a few examples.

APIX: Analysis From Pixellated Inputs in Early Design Using a Pen-Based Interface

“…They provide a solution for linear 3D stress problems where the input is the native acquire data of physical artifacts (like sculptures and mechanical parts) through sampling. The tool, APIX, presented in this paper is an extension of FEAsy developed by Murugappan et al [27], a sketch-based interface for static structural analysis of online sketches. APIX supports input from a variety of offline sketches and images allowing for easy modification and re-use of existing geometries for quick structural and thermal analysis.…”

“…Our approach to transforming the input to formalized representations (i.e. beautification) is based on the architecture in [27]. There are five steps in the pipeline namely -resampling, segmentation, recognition, merging and geometry constraint solving.…”

“…10(b)(d) shows the results of classification of stroke-groups into text (black) and symbols (blue). For symbol recognition, we use similar heuristic based rules as [27] to recognize different symbols. The reason behind using such an approach is that the number of symbols in this set is finite and each symbol has some distinct properties that can be used to differentiate from the other symbols in spite of the possible variations.…”

Sketching as a tool for knowledge management

“…Most of the articles found during our literature domain. The reason for this circumstance is most likely the following fact: While the potential advantages of freehand sketches as being an efficient and natural way for users to visually communicate ideas have been widely recognized and exploited, it is still a major challenge to transform those informal and ambiguous freehand inputs into more formalized and structured digital representations [21]. The same explanation for the occupation of sketching in the realm of user interface approaches for computer systems, and CAD systems in particular, can be found in Shpitalni and Lipsons work: natural communication language, enabling faster conveyance of qualitative information while not burdening the creativity of the [23].…”

“…Externalization of ideas and shared meanings [26], [10], [19] Relieves limited working memory [26] Facilitates information processing and communication [26], [12], [22], [15], [21], [28], [18], [23] Promotes efficient and enjoyable collaboration and establishes a joint focus [26], [10], [19], [13] Leads to better listening and engagement of the team members [10], [19] Enhances accessibility of ideas and building on earlier ideas [27], [17] Knowledge Documentation Becomes instant documentation for subsequent reference or later analysis [19], [22], [5], [20], [24] Builds a collective graphic memory which facilitates archiving and retrieval of information…”