Modelling free-form surfaces using a feature-based approach

International audienceThe use of free-form shapes has become mainstream to design complex products that have to fulfil engineering requirements as well as aesthetic criteria. Even if today’s CAD systems can easily represent free-form shapes by means of NURBS surfaces, their definition and modification still require a deep knowledge and a great skill in the manipulation of the underlying mathematical models. The implemented free-form shapes design operators are time consuming and do not enable fast modifications. To overcome these limits, some researches have been undertaken to try to adapt the feature concept, successfully adopted for the design of regular shapes, in the free-form domain. It gives rise to a set of free-form features modelling strategies. This paper gathers together the state-of-the-art of these advances. The various approaches are depicted and compared with respect to a very precise set of criteria expressing the needs in aesthetic and engineering designs. The limits and future trends are presente

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“…push, pull, qÈ, Pernot et al [21]. To select the d-F 4 to be instantiated, a complete feature classification [18] has been proposed (fÈ).…”

Section: Fully Free-form Features (F 4 )mentioning

confidence: 99%

Incorporating free-form features in aesthetic and engineering product design: State-of-the-art report

Pernot

Falcidieno

Giannini

et al. 2008

Computers in Industry

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“…The detailed geometric models are automatically converted to the base domain surface and the displacement map representations using a unified subdivision framework. Pernot et al couple a feature-based approach and a surface deformation method for free form design to overcome the limits of free form surface manipulation [22]. Khodakovsky and Schroder describe a technique allowing the interactive creation and manipulation of fine scale feature curves on subdivision surfaces [23].…”

Section: 2mentioning

confidence: 99%

A GPU based interactive modeling approach to designing fine level features

Huang

Wang

2007

Proceedings of Graphics Interface 2007 on - GI '07

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In this paper we propose a GPU based interactive geometric modeling approach to designing fine level features on subdivision surfaces. Displacement mapping is a technique for adding fine geometric detail to surfaces by using two-dimensional height map to produce photo-realistic surfaces. Due to space inefficiency and time consuming to render displacement map, this technique is generally limited in offline cinematic content creation packages. We propose a new approach to designing fine level features on subdivision surfaces via displacement mapping interactively on the latest GPU. Our method can reduce the bandwidth of the graphics channel by generating complex geometric detail on GPU, without feeding a large number of vertices to the AGP or PCI-E. Moreover, we introduce feature modification tools to flexibly control and adjust the created features. Designers can preview the features at the rendering stage, saving the time to generate the satisfying features on surfaces. The proposed approach is efficient and robust, and can be applied in many interactive graphics applications such as computer gaming, geometric modeling and computer animation.

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“…The methods that manage control vertices were proposed in [10][11][12]. In these methods, constraints are imposed on the line segments connecting control vertices.…”

Section: Background and Related Researchmentioning

confidence: 99%

“…Parametric modeling methods for freeform models developed so far can be categorized into two classes: 1) those that impose geometric constraints on the control vertices of parametric surfaces and 2) those that utilize freeform features [9][10][11][12][13][14]. These approaches are only applicable to the models composed of parametric surfaces such as Non Uniform rational B-Spline (NURBS).…”

Section: Introductionmentioning

confidence: 99%

A new parametric control method for freeform mesh models

Park

Lee

2005

Int J Adv Manuf Technol

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Parametric modeling technology is difficult to apply to freeform mesh models since there is no efficient way to impose geometric constraints. In this paper, we propose a novel method to control freeform mesh models parametrically. Our approach is to construct a control mesh that surrounds an object model and then impose constraints on it. The control mesh is parametrically controlled and the shape of the object model is modified by using an existing freeform deformation method.This paper is mainly concerned with automated construction of a control mesh and treatment of geometric constraints. Procedures for creating a control mesh are as follows: 1) determine the optimal orientation of the model, 2) project the model along three axes and extract contours, 3) create 2D control polygons for the contours, and 4) construct the 3D control mesh from the 2D control polygons. Geometric constraints are imposed on the edges and faces of a control mesh. Types of constraints are given by either a relative relationship between elements or an absolute displacement. A new control mesh is calculated by solving these constraints and the original model is modified accordingly. We tested our algorithms for two freeform models.

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Modelling free-form surfaces using a feature-based approach

Cited by 13 publications

References 16 publications

Incorporating free-form features in aesthetic and engineering product design: State-of-the-art report

Incorporating free-form features in aesthetic and engineering product design: State-of-the-art report

A GPU based interactive modeling approach to designing fine level features

A new parametric control method for freeform mesh models

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