EMAIL: bsieker@techfak.uni-bielefeld.de NAME: Bernd Sieker TOPIC: glass COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT. TITLE: oillamp COUNTRY: Germany WEBPAGE: http://psybert.uni-bielefeld.de/~bsieker/ RENDERER USED: Real3D V3.5 TOOLS USED: ArtEffect Paint Program, NetPBM RENDER TIME: 57 Hours HARDWARE USED: Amiga 4000, WarpEngine MC68040-40, 30 MB RAM. IMAGE DESCRIPTION: The image shows a setting of some items, most of them made of glass, on a table whith a wooden rim and tiles on top. DESCRIPTION OF HOW THIS IMAGE WAS CREATED: (although this is not POVray some of it may be helpful to POV users, which is what this competition is all about, I guess.) The image was entirely created with Real3D Version 3.5 on an Amiga 4000 with a WarpEngine 4040 with 30 MB RAM. All objects were created especially for this image and modelled by me alone. Some textures are part of the Real3D V3.5 package, others were found at various sites in the Internet, some I have painted myself using ArtEffect. Some of the objects are CSG: the room, the table, the blue oil lamp body and the flames. Others are B-spline meshes: The clear glass oil lamp, the wicks, the dish, the fruits. The table consists of a hexagonal polyhedron used as a base for something to be seen between the tiles and the wooden rim. The tiles also consist of a smaller hexagonal polyhedron, color and bump mapped with appropriate textures. The wooden rim was made of six identical "pies", that were created of a complex CSG object to form the rounded edge. Each pie was then rotated an additional 60 degrees. The triangular blue oil lamp is a very simple CSG object, consisting of only two subtractedd cut pyramids and a cylinder for the wick hole. The wick was made by "sweeping" a circular b-spline curve along another b-spline curve. the oil was modelled using another cut pyramid a tiny bit smaller than the interiour of the lamp body, colouring it red and giving appropriate refractive index to it. The lamp body has an algorithmical "noise" bump map attached to it. The other oil lamp was made rotating a b-spline curve around an axis, creating the complete shape in one step, including the opening. For the oil itself, the spline mesh of the body was duplicated, its u and v coordinates swapped and the shape was divided into a number of circular b-spline curves. The curves not needed were deleted, the remaining ones corrected to represent the oil shape and then made into a mesh again. A top plate was added (using a primitive rectangle and a b-spline "trim curve", since now the oil was just an open dish. It was then shrunk a very little bit to avoid accuracy problems, and coloured red. The star shaped glass dish stand was originally created by rotating a simple profile around an axis. then every second "knot" curve was selected and shrunk towards the center, creating the star like shape. I had used an object similar to this one in earlier (unpublished) scenes, but recreated this one from scratch. (It's quite easy with Real3D once you know how to do it.) The fruit are very simple B-spline objects, the apple has a hand-painted but algorithmically distorted colour map and a slight noise bump map, the Orange has no special color map and a slightly stronger noise bump map than the apple. The flames consist of some very simple CSG. They also contain the only light sources in the scene. This is the reason why I used such prominent lens flare effects. (Although they are called post effects in Real3D they are really created in the rendering process by the 3D program and thus cannot be considered illegal post processing.) In real photography taking a picture of a scene including the only illuminating light sources will produce a very strong glow around the source. (I think partially caused by grease on the lens and partially be the film and the camera back wall themselves diffusing some of the light to the surrounding area). The main streaks, however, are usually created by some special effect filter. The smaller random streaks are caused by small scratches on the lens. The sub flares are caused by internal reflections between the lenses. Real3D simulates caustics for glass shadows by brightening the central areas of them. While this is fine when using simple glass objects, when using multiple glass objects between the light and shadowed areas, this produces unwanted light amplification. To avoid this I had to insert a very dense shadow fog object into the left clear glass lamp. This object is only visible to the shadow calculations, not to the primary rays, neither to reflected/refracted rays. Real3D offers special attributes for this (called "scene" and "not reflected", the latter including 'not visible through transparent objects'). For simple glass objects, however, Real3D's method produces a good caustic simulation that looks a lot better than "flat" glass shadows. I used the default adaptive antialiasing and focal blur (called DOF, depth of field) of Real3D. You need at least version 3.5 of Real3D to load the scenes. There is a 3.5 demo CD containing the demo version and most of the textures I used. If you have any problems examining the scene, contact me by private email. I am also on the IRTC mailing list. It should be loadable with the Amiga and the Windows versions, although the Interface layout was designed for my Amiga screen and may look strange under Windows. I did no post-processing to the image except converting it to a 98-quality-JPEG. The lens flares were created by the raytracer.