Free isosurfaces software for linux

The Persistence of Vision Ray-Tracer creates three-dimensional, photo-realistic images using a rendering technique called ray-tracing. It reads in a text file containing information describing the objects and lighting in a scene and generates an image of that scene from the view point of a camera also described in the text file.
The Persistence of Vision Ray-Tracer(tm) was developed from DKBTrace 2.12 (written by David K. Buck and Aaron A. Collins) by a bunch of people (called the POV-Team?) in their spare time. The headquarters of the POV-Team is on the internet (see "Where to Find POV-Ray Files" for more details).
The POV-Ray package includes detailed instructions on using the ray-tracer and creating scenes. Many stunning scenes are included with POV-Ray so you can start creating images immediately when you get the package. These scenes can be modified so you do not have to start from scratch.
In addition to the pre-defined scenes, a large library of pre-defined shapes and materials is provided. You can include these shapes and materials in your own scenes by just including the library file name at the top of your scene file, and by using the shape or material name in your scene.
Ray-tracing is not a fast process by any means, but it produces very high quality images with realistic reflections, shading, perspective and other effects.
Ray-tracing is a rendering technique that calculates an image of a scene by simulating the way rays of light travel in the real world. However it does its job backwards. In the real world, rays of light are emitted from a light source and illuminate objects. The light reflects off of the objects or passes through transparent objects. This reflected light hits our eyes or perhaps a camera lens. Because the vast majority of rays never hit an observer, it would take forever to trace a scene.
Ray-tracing programs like POV-Ray start with their simulated camera and trace rays backwards out into the scene. The user specifies the location of the camera, light sources, and objects as well as the surface texture properties of objects, their interiors (if transparent) and any atmospheric media such as fog, haze, or fire.
For every pixel in the final image one or more viewing rays are shot from the camera, into the scene to see if it intersects with any of the objects in the scene. These "viewing rays" originate from the viewer, represented by the camera, and pass through the viewing window (representing the final image).
Every time an object is hit, the color of the surface at that point is calculated. For this purpose rays are sent backwards to each light source to determine the amount of light coming from the source. These "shadow rays" are tested to tell whether the surface point lies in shadow or not. If the surface is reflective or transparent new rays are set up and traced in order to determine the contribution of the reflected and refracted light to the final surface color.
Special features like inter-diffuse reflection (radiosity), atmospheric effects and area lights make it necessary to shoot a lot of additional rays into the scene for every pixel.
Main features:
- Easy to use scene description language.
- Large library of stunning example scene files.
- Standard include files that pre-define many shapes, colors and textures.
- Very high quality output image files (up to 48-bit color).
- 16 and 24 bit color display on many computer platforms using appropriate hardware.
- Create landscapes using smoothed height fields.
- Many camera types, including perspective, orthographic, fisheye, etc.
- Spotlights, cylindrical lights and area lights for sophisticated lighting.
- Photons for realistic, reflected and refracted, caustics. Photons also interact with media.
- Phong and specular highlighting for more realistic-looking surfaces.
- Inter-diffuse reflection (radiosity) for more realistic lighting.
- Atmospheric effects like atmosphere, ground-fog and rainbow.
- Particle media to model effects like clouds, dust, fire and steam.
- Several image file output formats including Targa, BMP (Windows only), PNG and PPM.
- Basic shape primitives such as ... spheres, boxes, quadrics, cylinders, cones, triangle and planes.
- Advanced shape primitives such as ... Tori (donuts), bezier patches, height fields (mountains), blobs, quartics, smooth triangles, text, superquadrics, surfaces of revolution, prisms, polygons, lathes, fractals, isosurfaces and the parametric object.
- Shapes can easily be combined to create new complex shapes using Constructive Solid Geometry (CSG). POV-Ray supports unions, merges, intersections and differences.
- Objects are assigned materials called textures (a texture describes the coloring and surface properties of a shape) and interior properties such as index of refraction and particle media (formerly known as "halos").
- Built-in color and normal patterns: Agate, Bozo, Bumps, Checker, Crackle, Dents, Granite, Gradient, Hexagon, Leopard, Mandel, Marble, Onion, Quilted, Ripples, Spotted, Spiral, Radial, Waves, Wood, Wrinkles and image file mapping. Or build your own pattern using functions.
- Users can create their own textures or use pre-defined textures such as ... Brass, Chrome, Copper, Gold, Silver, Stone, Wood.
- Combine textures using layering of semi-transparent textures or tiles of textures or material map files.
- Display preview of image while rendering (not available on all platforms).
- Halt and save a render part way through, and continue rendering the halted partial render later.

ParaView project is an application designed with the need to visualize large data sets in mind. The goals of the ParaView project include the following:
- Develop an open-source, multi-platform visualization application.
- Support distributed computation models to process large data sets.
- Create an open, flexible, and intuitive user interface.
- Develop an extensible architecture based on open standards.
ParaView runs on distributed and shared memory parallel as well as single processor systems and has been succesfully tested on Windows, Linux and various Unix workstations and clusters. Under the hood, ParaView uses the Visualization Toolkit as the data processing and rendering engine and has a user interface written using a unique blend of Tcl/Tk and C++. Please go here for a detailed list of features.
ParaView was created by Kitware in conjunction with Jim Ahrens of the Advanced Computing Laboratory at Los Alamos National Laboratory (LANL). Contributors and developers of ParaView currently include: Kitware, LANL, Sandia National Laboratories, and Army Research Laboratory. ParaView is funded by the US Department of Energy ASCI Views program as part of a three-year contract awarded to Kitware, Inc. by a consortium of three National Labs - Los Alamos, Sandia, and Livermore. The goal of the project is to develop scalable parallel processing tools with an emphasis on distributed memory implementations. The project includes parallel algorithms, infrastructure, I/O, support, and display devices. One significant feature of the contract is that all software developed is to be delivered open source. Hence ParaView is available as an open-source system.
Main features:
- Handles structured (uniform rectilinear, non-uniform rectilinear, and curvilinear grids), unstructured, polygonal and image data.
- All processing operations (filters) produce datasets. This allows the user to either further process or save as a data file the result of every operation. For example, the user can extract a cut surface, reduce the number of points on this surface by masking, and apply glyphs (for example, vector arrows) to the result.
- Contours and isosurfaces can be extracted from all data types using scalars or vector components. The results can be colored by any other variable or processed further. When possible, structured data contours/isosurfaces are extracted with fast and efficient algorithms which make use of the special data layout.
- Vectors fields can be inspected by applying glyphs (arrows, cones, lines, spheres, and various 2D glyphs) to the points in a dataset. The glyphs can be scaled by scalars, vector component or vector magnitude and can be oriented using a vector field.
- A sub-region of a dataset can be extracted by cutting or clipping with an arbitrary plane (all data types), specifying a threshold criteria to exclude cells (all data types) and/or specifying a VOI (volume of interest - structured data types only)
- Streamlines can be generated using constant step or adaptive integrators. The results can be displayed as points, lines, tubes, ribbons, etc., and can be processed by a multitude of filters.
- The points in a dataset can be warped (displaced) with scalars (given a user defined displacement vector) or with vectors (unavailable for non-linear rectilinear grids).
- With the array calculator, new variables can be computed using existing point or cell field arrays. A multitude of scalar and vector operations are supported.
- Data can be probed at a point or along a line. The results are displayed either graphically or as text and can be exported for further analysis.
- ParaView provides many other data sources and filters by default (edge extraction, surface extraction, reflection, decimation, extrusion, smoothing...) and any VTK filter can be added by providing a simple XML description (VTK provides hundreds of sources and filters, see VTK documentation for a complete list).
Enhancements:
- This release adds parallel uniform rectilinear grid volume rendering (vtkImageData).
- It introduces new algorithms for parallel unstructured grid volume rendering.
- Support for hardware accelerated offscreen rendering using OpenGL framebuffers.
- Improved multi-block support.
- Improved AMR support.
- Animation saving with ffmpeg.
- Filters have been added for FLUENT, OpenFOAM, MFIX, LSDyna, and AcuSolve.
- A gradient filter for unstructured data.
- Many other enhancements and bugfixes.