Direct trimming of NURBS surfaces on the GPU

Schollmeyer, Andre; Fröhlich, Bernd

doi:10.1145/1576246.1531353

Cited by 6 publications

(7 citation statements)

References 18 publications

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“…This includes multi-pass techniques, as well as ray-casting based rendering approaches. This extensibility is demonstrated by the current support for trimmed NURBS [SF09], level-of-detail point clouds and 3D video avatars [BKKF13]. During fragment processing, each renderer passes the information necessary to defer shading to a shared shader interface which is independent of the type of geometry.…”

Section: System Overviewmentioning

confidence: 99%

Order-Independent Transparency for Programmable Deferred Shading Pipelines

Schollmeyer

Babanin

Froehlich

2015

Computer Graphics Forum

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a) (b) (c) Figure 1: These are some image results for rendering an engine model using our pipeline. For the fully transparent engine (a), our system performs at about 60Hz. If only some parts are transparent (b), it runs at about 180Hz. The opacity remains programmable at fragment level which enables adaptive interaction tools, e.g. virtual see-through lenses (c). AbstractIn this paper, we present a flexible and efficient approach for the integration of order-independent transparency into a deferred shading pipeline. The intermediate buffers for storing fragments to be shaded are extended with a dynamic and memory-efficient storage for transparent fragments. The transparency of an object is not fixed and remains programmable until fragment processing, which allows for the implementation of advanced materials effects, interaction techniques or adaptive fade-outs. Traversing costs for shading the transparent fragments are greatly reduced by introducing a tile-based light-culling pass. During deferred shading, opaque and transparent fragments are shaded and composited in front-to-back order using the retrieved lighting information and a physically-based shading model. In addition, we discuss various configurations of the system and further enhancements. Our results show that the system performs at interactive frame rates even for complex scenarios.

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Section: System Overviewmentioning

confidence: 99%

Order-Independent Transparency for Programmable Deferred Shading Pipelines

Schollmeyer

Babanin

Froehlich

2015

Computer Graphics Forum

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“…face, which is then decomposed into multiple rational Bézier patches [CLR80]. Trimming curves are also similarly transformed into NURBS curves and split up into multiple rational Bézier curves, which are finally gathered in a trim structure [SF09]. The trim structure is used to do the trimming of individual fragments every time this is needed.…”

Section: Our Algorithmmentioning

confidence: 99%

“…Each rendered fragment goes through the trimming process [SF09], and off-face fragments are discarded. For onface fragments, alongside the fragment color, we store in a framebuffer-sized metadata buffer the Bézier patch ID, the parent B-Rep face ID, as well as the u, v coordinate of the fragment in the parametric space of the Bézier patch.…”

Section: Step 1: Initial Renderingmentioning

confidence: 99%

“…If it does, we look up the u, v coordinate resulting from the Newton iteration in the trim structure to determine if the intersection actually lies on the B-Rep face. This follows the fragment classification method of Schollmeyer and Fröhlich [SF09]. If the Newton iterations do not converge, or if the trim structure lookup reveals the fragment is off the face, execution continues on to the next neighboring fragment.…”

Section: 42a Ray-casting B-rep Faces At Crack Locationsmentioning

confidence: 99%

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Crack‐free rendering of dynamically tesselated B‐rep models

Claux

Barthe

Vanderhaeghe

et al. 2014

Computer Graphics Forum

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“…Hardware and implementation independent values are Ntest in the 8th column, showing the reduction of exact odd-even tests by shooting horizontal ray and Ntrav with the average number of traversal steps through the trimming data structure per trimming test. Absolute values are reported for the reference method 3-HS[SF09] except the 9th column with a memory consumption that uses as reference the method 1 − L…”

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confidence: 99%

Optimizing Ray Tracing of Trimmed NURBS Surfaces on the GPU

Sloup

Havran

2021

Computer Graphics Forum

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The representation of geometric models by trimmed NURBS surfaces has become a standard in the CAD industry. In CAD applications, the rendering of surfaces is usually solved by tessellation followed up by z‐buffer rendering. Ray tracing of NURBS surfaces has not been widely used in industry due to its computational complexity that hinders achieving real‐time performance in practice. We propose novel methods achieving faster point location search needed by trimming in the context of ray tracing trimmed NURBS surfaces. The proposed 2D data structure based on kd‐trees allows for faster ray tracing while it requires less memory for its representation and less preprocessing time than previously published methods. Further, we show the current state of the art for ray tracing trimmed NURBS surfaces on a GPU. With careful design and implementation, the number of rays cast on a GPU may reach real‐time performance in the order of tens to hundreds of million rays per second for moderately to large complex scenes containing hundreds of thousands of NURBS surfaces and trimming curves.

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Direct trimming of NURBS surfaces on the GPU

Cited by 6 publications

References 18 publications

Order-Independent Transparency for Programmable Deferred Shading Pipelines

Order-Independent Transparency for Programmable Deferred Shading Pipelines

Crack‐free rendering of dynamically tesselated B‐rep models

Optimizing Ray Tracing of Trimmed NURBS Surfaces on the GPU

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