Real-time rendering of deformable parametric free-form surfaces

1999 ◽  
Author(s):  
Frederick W. B. Li ◽  
Rynson W. H. Lau
Keyword(s):  
Real Time ◽  
Free Form ◽  
Free Form Surfaces

Application of Haptic Navigation to Modify Free-Form Surfaces Through Specified Points and Curves

2002 ◽  
Vol 2 (4) ◽  
pp. 265-276 ◽  
Author(s):  
Masatake Higashi ◽  
Nobuaki Aoki ◽  
Takanobu Kaneko
Keyword(s):  
Real Time ◽  
Force Feedback ◽  
Correction Function ◽  
Free Form ◽  
Cardinal Spline ◽  
Trimmed Surface ◽  
Pass Through ◽  
Free Form Surfaces ◽  
The Given ◽  
Haptic Sensation

In this paper, we propose a method which modifies free-form surfaces to pass through not only specified points, but also specified curves with the assistance of haptic navigation. Using the method, designers of aesthetic shapes, such as a car body, can manipulate the model of the shape in real-time looking at its stereoscopic image and feeling its haptic sensation as if there were a clay model. The haptic navigation helps designers, letting them capture and recognize the object easily and constraining their operation to the appropriate direction or along the specified geometric element. In addition, the designers can get force feedback proportional to the modification quantity. To obtain a smoothly modified shape, we introduce correction functions to the given surface equations. A correction function distributes the effect of the change over the whole shape or the specified region according to the distance of the point in the normal direction of the given surface. The values of the correction function are 1 at the indicated point and 0 at the boundaries, and the shape is modified to keep the original smoothness. The correction values of the functions at the indicated points are determined to pass through all of them by solving a linear equation. To apply this to the specified curves including boundaries of a trimmed surface, we treat points composing the curve similarly to the point specification by representing them with a Cardinal spline. We have confirmed that the system is effective to manipulate a shape with its feeling and that smooth surfaces are obtained in real time as designers want.

Real Time Machinability Analysis of Free Form Surfaces on the GPU

2007 ◽  
Author(s):  
Mikola Lysenko ◽  
Keyvan Rahmani ◽  
Roshan D’Souza
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
Three Dimensional ◽  
Free Form ◽  
Complex Objects ◽  
Cad System ◽  
Solid Models ◽  
Early Design Stages ◽  
Graphics Processing ◽  
Free Form Surfaces

In this paper a new hardware accelerated method is presented to evaluate the machinability of free-form surfaces. This method works on tessellated models that are commonly used by CAD systems to render three-dimensional shaded images of solid models. Modern Graphics Processing Units (GPUs) can be programmed in hardware to accelerate specialized rendering techniques. In this research, we have developed new algorithms that utilize the programmability of GPUs to evaluate machinability of free-form surfaces. The method runs in real time on fairly inexpensive hardware (<$600), and performs well regardless of the surface type. The complexity of the method is dictated by the size of the projected view of the model. The proposed method can be used as a plug-in in a CAD system to evaluate manufacturability of a part at early design stages. The efficiency and the speed of the proposed method are demonstrated on some complex objects.

Real-Time Machinability Analysis of Free Form Surfaces on the GPU

2009 ◽  
Vol 9 (2) ◽  
Author(s):  
Mikola Lysenko ◽  
Roshan D’Souza ◽  
Keyvan Rahmani
Keyword(s):  
Real Time ◽  
Computer Aided Design ◽  
Graphics Processing Units ◽  
Three Dimensional ◽  
Free Form ◽  
Complex Objects ◽  
Cad System ◽  
Solid Models ◽  
Aided Design ◽  
Free Form Surfaces

In this paper a new hardware accelerated method is presented to evaluate the machinability of free-form surfaces. This method works on tessellated models that are commonly used by computer aided design (CAD) systems to render three-dimensional shaded images of solid models. Modern graphics processing units (GPUs) can be programed in hardware to accelerate specialized rendering techniques. In this research, we have developed new algorithms that utilize the programmability of GPUs to evaluate the machinability of free-form surfaces. The method runs in real-time on fairly inexpensive hardware (<$600), and performs well regardless of the surface type. The complexity of the method is dictated by the size of the projected view of the model. The proposed method can be used as a plug-in in a CAD system to evaluate the manufacturability of a part at early design stages. The efficiency and the speed of the proposed method are demonstrated on some complex objects.

Real Time Curve Extrapolator for Fixtureless Inspection of Freeform Surfaces

2006 ◽  
Author(s):  
D. Steiner
Keyword(s):  
Real Time ◽  
Reference Plane ◽  
Free Form ◽  
Depth Of Field ◽  
Test Cases ◽  
Sampled Data ◽  
Time Curve ◽  
Small Depth ◽  
Manufacturing Process Control ◽  
Free Form Surfaces

The inspection of free-form surfaces is an important task in manufacturing process control. This task motivated researchers to develop methodologies and technologies for fixtureless inspection. The motivation for performing fixtureless inspection rises from the fact that a datum or an exact fixture is not always available for free-form objects. When datum and fixtures are not present, the location and rotation of the object in space relative to the sensor coordinate system are unknown. Thus, scanning along a proper trajectory is not trivial especially when dealing with high precision sensors with small depth of field (DOF). In this paper we introduce a theoretical scheme for real time curve extrapolation. This scheme performs real time automatic adjustment to the sensor depth of field by smoothly changing the position of the sensor. The proposed scheme can handle local C1 discontinuity (C0 continuity). In the proposed scheme, the velocity of the motion stages can be controlled by the curvature of the extrapolated curve, thus controlling the density of the sampled data. Also, no knowledge of the surface orientation and location is needed nor any reference plane or other datum. The scheme was tested using computer simulation that was developed for this purpose. The robustness of the scheme is shown at the end of this paper through simulation results using high order polynomial surfaces as test cases.

Development of a STEP-NC Controller for 5-Axis Machining of NURBS Surfaces

2011 ◽  
Vol 317-319 ◽  
pp. 1940-1948
Author(s):  
Xia Li ◽  
Hong Bin Liang
Keyword(s):  
Machine Tool ◽  
Real Time ◽  
Information Exchange ◽  
Free Form ◽  
Cnc System ◽  
Cad Cam ◽  
Nurbs Surfaces ◽  
Free Form Surfaces ◽  
Conventional Machining ◽  
Rotary Type

In conventional machining of free form surfaces, incomplete information exchange between CNC and CAD/CAM results in many limitations need to be rectified. In the paper, a new structure of CNC based on STEP-NC is proposed. A 5-axis real-time interpolator for NURBS surfaces machining is realized. A STEP-NC controller has been developed, which is a software modular CNC system. The CNC system has been installed on a tilt-rotary type 5-axis machine tool. The milling experiment has been performed.

scholarly journals Construction and analysis of unified 4-point interpolating nonstationary subdivision surfaces

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Mehwish Bari ◽  
Ghulam Mustafa ◽  
Abdul Ghaffar ◽  
Kottakkaran Sooppy Nisar ◽  
Dumitru Baleanu
Keyword(s):  
Computer Graphics ◽  
Geometric Modeling ◽  
Tension Control ◽  
Free Form ◽  
Subdivision Surfaces ◽  
Smooth Curves ◽  
Practical Applications ◽  
Tension Parameter ◽  
Exact Reproduction ◽  
Free Form Surfaces

AbstractSubdivision schemes (SSs) have been the heart of computer-aided geometric design almost from its origin, and several unifications of SSs have been established. SSs are commonly used in computer graphics, and several ways were discovered to connect smooth curves/surfaces generated by SSs to applied geometry. To construct the link between nonstationary SSs and applied geometry, in this paper, we unify the interpolating nonstationary subdivision scheme (INSS) with a tension control parameter, which is considered as a generalization of 4-point binary nonstationary SSs. The proposed scheme produces a limit surface having $C^{1}$ C 1 smoothness. It generates circular images, spirals, or parts of conics, which are important requirements for practical applications in computer graphics and geometric modeling. We also establish the rules for arbitrary topology for extraordinary vertices (valence ≥3). The well-known subdivision Kobbelt scheme (Kobbelt in Comput. Graph. Forum 15(3):409–420, 1996) is a particular case. We can visualize the performance of the unified scheme by taking different values of the tension parameter. It provides an exact reproduction of parametric surfaces and is used in the processing of free-form surfaces in engineering.

Automatic Generation of Anisotropic Patterns of Geometric Features for Industrial Design

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Diego Andrade ◽  
Ved Vyas ◽  
Kenji Shimada
Keyword(s):  
Boundary Conditions ◽  
Computer Aided Design ◽  
Industrial Design ◽  
Automatic Generation ◽  
Free Form ◽  
Geometric Features ◽  
Target Domain ◽  
Metric Tensor ◽  
Target Region ◽  
Free Form Surfaces

While modern computer aided design (CAD) systems currently offer tools for generating simple patterns, such as uniformly spaced rectangular or radial patterns, these tools are limited in several ways: (1) They cannot be applied to free-form geometries used in industrial design, (2) patterning of these features happens within a single working plane and is not applicable to highly curved surfaces, and (3) created features lack anisotropy and spatial variations, such as changes in the size and orientation of geometric features within a given region. In this paper, we introduce a novel approach for creating anisotropic patterns of geometric features on free-form surfaces. Complex patterns are generated automatically, such that they conform to the boundary of any specified target region. Furthermore, user input of a small number of geometric features (called “seed features”) of desired size and orientation in preferred locations could be specified within the target domain. These geometric seed features are then transformed into tensors and used as boundary conditions to generate a Riemannian metric tensor field. A form of Laplace's heat equation is used to produce the field over the target domain, subject to specified boundary conditions. The field represents the anisotropic pattern of geometric features. This procedure is implemented as an add-on for a commercial CAD package to add geometric features to a target region of a three-dimensional model using two set operations: union and subtraction. This method facilitates the creation of a complex pattern of hundreds of geometric features in less than 5 min. All the features are accessible from the CAD system, and if required, they are manipulable individually by the user.

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