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The code MD_render

The pictures are results of the MD_render code (Int. J. Mod. Phys. C, 15, (2004), Large-Scale Molecular-Dynamics Simulation of 19 Billion particles by K. Kadau, T.C. Germann, and P.S. Lomdahl). The program renders spheres, cylinders, and arrows in a perspective manner. Utilization of the Message Passing Interface for parallel processing of the rendering process, with almost 100% efficiency, allows to render several millions of objects in a timely fashion. Due to a pre-sorting of objects the computational wall-clock time is under-proportional to the number of objects. Two light sources can be positioned and the spheres can generate shadows on all other objects (solid walls can also be positioned). Due to the pre-sorting of objects, the shadow-calculation wall-clock time rises slower than the square of the number of objects (which is the scaling for a brute force shadow calculation). The resulting picture has no limited pixel resolution with a 24 bit color-depth (approx 17 million colors), and can be written directly into a picture file. The user can specify different levels of anti-aliasing. The implementation can be done on every platform having an ANSI-C compiler, no graphic libraries are needed, since the code implements its own graphic functions. Large-scale simulations, in particular massive-parallel molecular-dynamics (MD), as for example represented by the SPaSM code, need to visualize a large number of objects like spheres or cylinders. While, there is a number of comercial and non-comercial software to fullfill that need, most of this software depends on specific graphics libraries and run only in a single-processor mode. The purpose of the code presented here, is to fill this gap, since the code is fully parallel and does not depend on any graphic-labraries, hence it is easy to install even on parallel machines.
By the way, the pictures and movies on the molecular-dynamics simulations movie page are rendered using a prototype version of that code. You can download a document about the code in pdf (17MB) here)

The first row shows the different light-contributions (from left to right): The emission-component (the only difference between emission and ambient is the influence of the ambient light source), the diffusive component, and the specular component add up the whole intensity (right). The second row demonstrates the effect of the light source position. The third row shows the influence of the shininess parameter (Mshi=1, 10, 100, 1000 (left to right)). The last row illustrates a second light-source with different color-components (white, red, green, yellow (left to right)).
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

The effect of anti-aliasing: The left scene was rendered without any anti-aliasing. For the right scene anti-aliasing was applied. The scene was rendered with spheres creating shadows. Anti-aliasing is especially important when objects consist of straight lines.
 
 

Example: The effect of multiple light sources and walls

Example: radial component of T2g mode of fcc

Example: 400 hundred Ising spins relaxing from an unordered state

Example: some more walls and shadows ...

Example: Cylinders in outer space

 
 

Example: 64,000 atoms arranged in the A11 Ga ground state structure (dimers are shown) creating shadows on each other

Example: 1,000,000 atoms arranged in the A11 structure

Example: Bond-structure of 64,000 atoms (32,000 bonds)

Example: Shadows on clustered spheres

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