Computer graphics, ray tracing, computer animation, rendering techniques
Suffern, KG 2007, Ray Tracing from the Ground Up, A K Peters Ltd, Wellesley, Massachusetts, USA.
Balsys, RJ, Harbinson, D & Suffern, KG 2012, 'Visualizing Nonmanifold and Singular Implicit Surfaces with Point Clouds', IEEE Transactions on Visualization and Computer Graphics, vol. 18, no. 2, pp. 188-201.View/Download from: Publisher's site
We use octree spatial subdivision to generate point clouds on complex nonmanifold implicit surfaces in order to visualize them. The new spatial subdivision scheme only uses point sampling and an interval exclusion test. The algorithm includes a test for pruning the resulting plotting nodes so that only points in the closest nodes to the surface are used in rendering. This algorithm results in improved image quality compared to the naive use of intervals or affine arithmetic when rendering implicit surfaces, particularly in regions of high curvature. We discuss and compare CPU and GPU versions of the algorithm. We can now render nonmanifold features such as rays, ray-like tubes, cusps, ridges, thin sections that are at arbitrary angles to the octree node edges, and singular points located within plot nodes, all without artifacts. Our previous algorithm could not render these without severe aliasing. The algorithm can render the self-intersection curves of implicit surfaces by exploiting the fact that surfaces are singular where they self-intersect. It can also render the intersection curves of two implicit surfaces. We present new image space and object space algorithms for rendering these intersection curves as contours on one of the surfaces. These algorithms are better at rendering high curvature contours than our previous algorithms. To demonstrate the robustness of the node pruning algorithm we render a number of complex implicit surfaces such as high order polynomial surfaces and Gaussian curvature surfaces. We also compare the algorithm with ray casting in terms of speed and image quality. For the surfaces presented here, the point clouds can be computed in seconds to minutes on a typical Intel based PC. Once this is done, the surfaces can be rendered at much higher frame rates to allow some degree of interactive visualization.
We are concerned with producing high-quality images of parametric and implicit surfaces, in particular those with non-manifold features. We present a point-based technique for rendering implicit surfaces that uses octree spatial subdivision with a natura
Harbinson, D, Balsys, R & Suffern, K 2019, 'Hybrid Polygon-Point Rendering of Singular and Non-Manifold Implicit Surfaces', 2019 23rd International Conference in Information Visualization – Part II, International Conference in Information Visualization – Part II, IEEE, Adelaide, Australia.View/Download from: Publisher's site
A hybrid polygons-points algorithm based on a hierarchical decomposition of the bounding volume using an octree spatial data structure, and testing cell occupation with interval arithmetic is given. Polygons are produced where curvature in occupied cells is low and points are used where curvature is high. As a result, points are rendered around extreme features and polygons around regular features. Using this approach implicit surfaces of high complexity, such as recursively defined curvature surfaces, are rendered. A discussion of the implementation is given for a GPU version of the algorithm and a comparison with GPU ray-casting is made. As the approach uses subdivision and it can be used for surface modelling. An advantage of the approach is the few artefacts that occur with singular points, cusps, rays and curves of self intersection. Production of antialiased animations and multiple views of the surface can be faster than in ray-casting. The algorithm is robust, renders singular and non-manifold surface and the algorithm works for algebraic and non-algebraic surfaces.
Harbinson, D, Balsys, RJ & Suffern, KG 2008, 'Real-time antialiasing of Edges and Contours of Point Rendered Implicit Surfaces', Fifth International Conference on Computer Graphics, Imaging and Visualization, International Conference Computer Graphics, Imaging and Visualization, IEEE Computer Society, Penang, pp. 38-46.View/Download from: Publisher's site
Balsys, RJ & Suffern, KG 2007, 'Point Based Rendering of Implicit 4-Dimensional Surfaces', International Conferences on Computer Graphics, Imaging and Vision, International Conference Computer Graphics, Imaging and Visualization, IEEE, Bangkok, Thailand, pp. 31-40.View/Download from: Publisher's site
We present a point based rendering algorithm that uses hyper-cubes to perform spatial subdivision in a 4D volume. A 4D function interval exclusion test is used to speed up the rendering of 4D Implicit surfaces in this hyper-volume. A 4D orthonormal basis function is used to define a 4D camera, which projects isometric or perspective views onto a plane in 4D for viewing. The technique requires evaluations of 4D implicit surface functions and gradients to render shaded images. The technique also allows for hidden surface elimination using a z-buffer modified for use in a 4D space. We give examples of its use in rendering some 4D surfaces and discuss problems with the technique. The algorithm can be generalised to higher dimensions.
Harbinson, D, Balsys, RJ & Suffern, KG 2007, 'Point Rendering on Non-Manifold Surface with Features', GRAHITE2007, ACM SIG International Conference on Computer Graphics and Interactive Techniques, The Association for Computing Machinery, Inc., Perth, Western Australia, pp. 47-53.
Balsys, RJ & Suffern, KG 2005, 'Adaptive polygonisation of non-manifold implicit surfaces', Computer Graphics, Imaging And Vision: New Trends, International Conference Computer Graphics, Imaging and Visualization, IEEE, Beijing, China, pp. 257-263.View/Download from: Publisher's site
We discuss the polygonisation and rendering of non-manifold implicit surfaces using adaptive octree subdivision and interval arithmetic for surface exclusion in octree nodes. We present a new algorithm that polygonises some surfaces that self intersect, or have other non-manifold features such as separate sections that meet at points. Gradient information is used to resolve ambiguous polygonisations in plotting nodes. A line-stitching algorithm is discussed that allows for multiple polygons to be in a plotting node. We illustrate the algorithm with a number of surfaces that demonstrate its capabilities and limitations.
Balsys, RJ & Suffern, KG 2004, 'Point based rendering of non-manifold surfaces with contours', Graphite 2004, International Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia, ACM SiGGRAPH, Singapore, pp. 7-14.View/Download from: Publisher's site
We present point based rendering techniques that render various types of contours as constant width slabs on surfaces. The techniques requires evaluations of the surface functions and gradients to render shaded images. We use slabs parallel to the principle planes, slabs located along a principal axis and rotated by arbitrary steps, slabs consisting of concentric spheres and slabs of constant Gaussian and mean curvatures. We also use the technique to render curvature maps of surfaces. We illustrate the techniques with a number of parametric and implicit surfaces, and discuss their advantages and disadvantages compared to other rendering techniques.
Jones, H, Balsys, RJ & Suffern, KG 2003, 'Point Based Rendering of Non Manifold Sufaces', Graphite2003 International Conference on Computer Graphics and Interactive Techniques in Australasia and South East Asia, International Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia, The Association for Computing Machinery, Inc., Melbourne, Australia, pp. 267-269.View/Download from: Publisher's site
We present a point based rendering technique that uses iterated function systems to render arbitrary parametric and implicit surfaces with singularities and non manifold features, to the pixel precision of the image. Its advantage over existing point based techniques is the simplicity of its implementation but in this form it is slow. It only requires evaluations of the surface functions and gradients to render shaded images. The technique also allows for hidden surface elimination using a z-buffer and shadow casting using a shadow buffer.
Suffern, KG 2000, 'Effective Instructional Animation in 3D Computer Graphics Education', Fourth Australasian Computing Education Conference, Association for Computing Machinery, Monash University, pp. 228-234.
Suffern, KG, 'Nebula and Blue', SIGGRAPH 2003, The Association for Computing Machinery Inc, ACM.
I have been writing ray tracers for 10 years to use in teaching, research, and computer art. In my art work I try to create images of great fractal complexity from the simplest possible scenes. Impact, Nebula, and Blue were created by ray tracing a single hollow black sphere with a mirror on its inner surface. The sphere normals are altered by a random bump map.