Omni‐directional Relief Impostors

Rendering detailed animated characters is a major limiting factor in crowd simulation. In this paper we present a new representation for 3D animated characters which supports output-sensitive rendering. Our approach is flexible in the sense that it does not require us to pre-define the animation sequences beforehand, nor to precompute a dense set of pre-rendered views for each animation frame. Each character is encoded through a small collection of textured boxes storing colour and depth values. At runtime, each box is animated according to the rigid transformation of its associated bone and a fragment shader is used to recover the original geometry using a dual-depth version of relief mapping. Unlike competing output-sensitive approaches, our compact representation is able to recover high-frequency surface details and reproduces view-motion parallax effectively. Our approach drastically reduces both the number of primitives being drawn and the number of bones influencing each primitive, at the expense of a very slight per-fragment overhead. We show that, beyond a certain distance threshold, our compact representation is much faster to render than traditional level-of-detail triangle meshes. Our user study demonstrates that replacing polygonal geometry by our impostors produces negligible visual artefacts.

Section: Related Workmentioning

confidence: 99%

A Flexible Approach for Output‐Sensitive Rendering of Animated Characters

Beacco¹,

Spanlang²,

Andújar³

et al. 2011

“…To better capture and render a 3D shape, the images can be layered [Sch98], pre‐warped [OBM00] or augmented with depth information, e.g. [PO06, ABB*07]. However, those methods are restricted to essentially opaque objects, and cannot represent objects that become fuzzy or semi‐transparent at a distance.…”

Section: Previous Workmentioning

confidence: 99%

Volumetric Billboards

Decaudin

Neyret

2009

International audienceWe introduce an image-based representation, called volumetric billboards, allowing for the real-time rendering of semi-transparent and visually complex objects arbitrarily distributed in a 3D scene. Our representation offers full parallax effect from any viewing direction and improved anti-aliasing of distant objects. It correctly handles transparency between multiple and possibly overlapping objects without requiring any primitive sorting. Furthermore, volumetric billboards can be easily integrated into common rasterization-based renderers, which allows for their concurrent use with polygonal models and standard rendering techniques such as shadow-mapping. The representation is based on volumetric images of the objects and on a dedicated real-time volume rendering algorithm that takes advantage of the GPU geometry shader. Our examples demonstrate the applicability of the method in many cases including levels-of-detail representation for multiple intersecting complex objects, volumetric textures, animated objects and construction of high-resolution objects by assembling instances of lowresolution volumetric billboards

“…[WWG07] presents free viewpoint video based on billboard rendering which is specialized to people as well. Similarly, [ABB*07] employ relief impostors in order to reconstruct visual appearance. However, a central component of the latter work is an optimization of the actual view positions.…”

Section: Related Workmentioning

confidence: 99%

Interactive Pixel‐Accurate Free Viewpoint Rendering from Images with Silhouette Aware Sampling

Hornung

Kobbelt

2009

We present an integrated, fully GPU-based processing pipeline to interactively render new views of arbitrary scenes from calibrated but otherwise unstructured input views. In a two-step procedure, our method first generates for each input view a dense proxy of the scene using a new multi-view stereo formulation. Each scene proxy consists of a structured cloud of feature aware particles which automatically have their image space footprints aligned to depth discontinuities of the scene geometry and hence effectively handle sharp object boundaries and occlusions. We propose a particle optimization routine combined with a special parameterization of the view space which enables an efficient proxy generation as well as robust and intuitive filter operators for noise and outlier removal. Moreover, our generic proxy generation allows us to flexibly handle scene complexities ranging from small objects up to complete outdoor scenes. The second phase of the algorithm combines these particle clouds in real-time into a view-dependent proxy for the desired output view and performs a pixel-accurate accumulation of the color contributions from each available input view. This makes it possible to reconstruct even fine-scale view-dependent illumination effects. We demonstrate how all these processing stages of the pipeline can be implemented entirely on the GPU with memory efficient, scalable data structures for maximum performance. This allows us to generate new output renderings of high visual quality from input images in real-time.