Real-time Terrain Rendering using Smooth Hardware Optimized Level of Detail

We present a method for real-time level of detail reduction that is able to display high-complexity polygonal surface data. A compact and efficient regular grid representation is used. The method is optimized for modern, low-end consumer 3D graphics cards. We avoid sudden changes of the geometry - also known as 'popping', when reducing the geometry by exploiting the low-level hardware programmability in order to maintain interactive framerates. Terrain models are repolygonized in order to minimizing the visible error. Furthermore, the method minimizes CPU usage during rendering and requires minimal pre-processing. We believe that this is the first time that a smooth level of detail has been implemented in commodity hardware

Optimizing Photon Mapping Using Multiple Photon Maps for Irradiance Estimates

The photon mapping method is used extensively in global illumination to render photorealistic pictures. We describe a simple optimization technique for calculating the indirect illumination by modifying the photon mapping method. Using our method the photon maps are divided into several photon maps based on the topology of the polygons in the scene. This modification of the photon mapping method has several advantages compared to the traditional method. We demonstrate that the indirect illumination can be calculated faster using our method

Protein and cell patterning in closed polymer channels by photoimmobilizing proteins on photografted poly(ethylene glycol) diacrylate

Definable surface chemistry is essential for many applications of microfluidic polymer systems. However, small cross-section channels with a high surface to volume ratio enhance passive adsorption of molecules that depletes active molecules in solution and contaminates the channel surface. Here, we present a one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of poly(ethylene glycol) (PEG), well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment. The coating consists of PEG diacrylate (PEGDA) covalently grafted to polymer surfaces via UV light activation of the water soluble photoinitiator benzoyl benzylamine, a benzophenone derivative. The PEGDA coating was shown to efficiently limit the adsorption of antibodies and other proteins to <5% of the adsorbed amount on uncoated polymer surfaces. The coating could also efficiently suppress the adhesion of mammalian cells as demonstrated using the HT-29 cancer cell line. In a subsequent equivalent process step, protein in aqueous solution could be anchored onto the PEGDA coating in spatially defined patterns with a resolution of <15 μm using an inverted microscope as a projection lithography system. Surface patterns of the cell binding protein fibronectin were photochemically defined inside a closed microfluidic device that was initially homogeneously coated by PEGDA. The resulting fibronectin patterns were shown to greatly improve cell adhesion compared to unexposed areas. This method opens for easy surface modification of closed microfluidic systems through combining a low protein binding PEG-based coating with spatially defined protein patterns of interest

Stereolithographic hydrogel printing of 3D culture chips with biofunctionalized complex 3D perfusion networks

Free-form mechanically stable 3D perfusion networks traversing and surrounding separate culture volumes are produced by light-induced 3D printing of PEGDA hydrogels.</p