Author Topic: Rendering Additional Particle Shapes  (Read 195 times)

NutsandBoltz

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Rendering Additional Particle Shapes
« on: April 06, 2018, 04:13:33 PM »
Hello!

I am curious if there is a straightforward way to render additional particle shapes (e.g., pentagons, hexagons), that does not involve scripting. I am running simulations with 2D squares, pentagons, and other polygons, and would like to be able to make some video files for illustrative purposes.

If it is necessary to script these shapes myself, does anyone have any recommendations or advice as to where to start? I have searched for plugins or scripts that do something similar, but I have so far been unsuccessful.

I apologize if my question is too broad or vague. I am very new to Ovito and hard particle simulations in general. Thanks for your time!

Alexander Stukowski

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Re: Rendering Additional Particle Shapes
« Reply #1 on: April 06, 2018, 05:56:16 PM »
Hi,

I'm sorry, but the current program version is not able to render more "exotic" particle shapes other then the standard shapes (sphere, ellipsoid, cube, cylinder, etc.).

In principle, you could implement a user-defined viewport overlay in Python script to render your polygonal particles using 2D drawing calls. But in my eyes that approach would not make much sense since you could achieve the same results without Ovito using pure Python and plotting frameworks such as matplotlib.

In general, I would be open to ideas and suggestions of how to extend Ovito in this direction and enable the visualisation of more complex particle shapes. But I myself am not really familiar with the corresponding simulation tools and common practices. It still seems to be a niche application with a small audience (compared to atomistic simulations, where particles are typically point-like). There are several open questions that need to be discussed in order to design a useful extension to Ovito, for instance:
  • What degree of freedom with respect to the particle shapes is desired (only regular convex polygons, arbitrary polygons, arbitrary polyhedra)?
  • How would the user specify the shape information?
  • Are there suitable file formats for transporting this information from the simulation codes to Ovito?
  • Is there a common ground between different simulation codes such as LAMMPS and HOOMD?

If you want, we can discuss these questions as you get yourself more familiar with the typical procedures (and visualisation needs) in this area of particle simulations.

NutsandBoltz

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Re: Rendering Additional Particle Shapes
« Reply #2 on: April 06, 2018, 07:31:13 PM »
Sure! My impression is that you're totally right - most visualization-oriented projects tend to focus on simple spherical/cubic/atomistic shapes that are already well handled by software like Ovito and VMD.

I'll focus on familiarizing myself with these types of simulations and with Ovito itself, but one suggestion I have is this:

With regards to how the user would specify shape information, my understanding is that STL file format is capable of conveying complex 3D geometries in a concise, well-standardized way. (I'm not sure how well it works for 2D geometries.) I regularly perform FDTD simulations on custom-made nanoparticle models, all of which I construct in STL format.

Thanks for the help!