nanoFluidX Auxiliary Tools for ParaView

Read in the post-processing state files and learn material library loading and how to install the nanoFluidX toolbar plugin.

Exporting State Files

To facilitate post-processing with ParaView, nanoFluidX and nFX[c] 2021.1 and above produce Python state files. These state files are intended as a starting point for post-processing needs and are fully compatible with ParaView 5.9.1 and above. The state files are written to the PVSTATE directory at the root of the case directory. nanoFluidX state files reference files from OUTPUT, PREVIEW, PHASEINFO, PROBE and MOTION directories. nFX[c] state file references files from PostJobName and MOTION directories. Currently there are four types of state files:

particles.py: This state file uses raw field data (particles) and may be slow. This state file will be loadable in ParaView 5.9.1.
1. Loads OUTPUT/particles.pvd and renames it to case name
2. Adds a Threshold filter per FLUID phase and renames them to the phase name
3. Adds an SPH Volume Interpolator per FLUID phase and sets spatial steps and resolution to dx and interpolation volume extents to domain size of the case.
4. Loads MOTION/motion_movingwalls.cfg UTM file, renames it to MOVINGWALLS and activates Ignore Time
5. Adds an Extract Block filter to allow selective visualization of MOVINGWALL phases
6. Loads MOTION/motion_walls.cfg UTM file, renames it to WALLS and activates Ignore Time
7. Adds an Extract Block filter to allow selective visualization of WALL phases and hides them
8. MOTION/*.cfg files load relevant UTM and STL files.
preview.py and PostJobName.py: These state files use interpolated field data and are the recommended state files for most post-processing needs. Thes state files will be loadable in ParaView 5.9.1.
1. Loads interpolated data:
  1. nanoFluidX: Loads PREVIEW/particles.pvd and renames it to case name
  2. nFX[c]: Loads PostJobName/AllVars/interpData.pvd and renames it to PostJobName
2. Loads MOTION/motion_movingwalls.cfg UTM file, renames it to MOVINGWALLS and activates Ignore Time
3. Adds an Extract Block filter to allow selective visualization of MOVINGWALL phases
4. Loads MOTION/motion_walls.cfg UTM file, renames it to WALLS and activates Ignore Time
5. Adds an Extract Block filter to allow selective visualization of WALL phases and hides them
6. MOTION/*.cfg files load relevant UTM and STL files.
phaseinfo_*.py: This state file is intended for quick reference to phaseinfo files. It plots most frequently used variables and may be used to follow the progress of a simulation during runtime. Using this file circumvents the need to import data in Microsoft Excel.
Note: All other variables not plotted by default are also accessible from the pipeline. Usable as of ParaView 5.9.0.
1. Loads all files under PHASEINFO and renames them to phasename Data
2. Adds a Plot Data filter per file and renames them to phasename Plot
3. Assigns a color to each variable in all phaseinfo files on a round robin basis. This is intended to reduce the chances of repeating colors on the same variable of different phaseinfo files.
4. Assigns a legend name to each variable as columnname phasename to help with distinguishing the lines in plot layouts.
5. Adds a spreadsheet layout
6. Adds the following layouts and sets the relevant axes titles per FLUID phaseinfo:
  1. Fluid CoM: FLUID phase center of mass in X, Y and Z
  2. Fluid nRho: number of particles satisfying $ρ / ρ 0 > 1.1$ and $ρ / ρ 0 > 1.2$ conditions for each FLUID phase
probeinfo_*.py: This state file is intended for quick reference to probeinfo files. It plots most frequently used variables and may be used to follow the progress of a simulation during runtime. Using this file circumvents the need to import data in Microsoft Excel.
Note: All other variables not plotted by default are also accessible from the pipeline. Usable as of ParaView 5.9.0.
1. Loads all files under PROBE and renames them to probename_probetype Data
2. Adds a Plot Data filter per file and renames them to probename_probetype Plot
3. Assigns a color to each variable in all probeinfo files on a round robin basis. This is intended to reduce the chances of repeating colors on the same variable of different probeinfo files.
4. Assigns a legend name to each variable as columnname probename_probetype to help with distinguishing the lines in plot layouts.
5. Adds a spreadsheet layout
6. Adds the following layouts and sets the relevant axes titles per volume probe:
  1. Volprobe Pressure: pressure versus time for each volume probe
  2. Volprobe Density: density versus time for each volume probe
7. Adds the following layouts and sets the relevant axes titles per surface and floowrate probes:
  1. Srf/flrprobe nPart: number of sampled particles versus time per probe
  2. Srf/flrprobe Velocity: average velocity of the sampled particles versus time per probe
  3. Srf/flrprobe Flowrate: total volume flowrate for all phases versus time per probe
8. Adds the following layouts and sets the relevant axes titles per solid probe:
  1. Sld probe Force: force versus time for each solid probe
  2. Sld probe Torque: torque versus time for each solid probe sampling a MOVINGWALL phase

Auxiliary Tools

ParaView is a powerful post-processing tool and in its open-end generality, it exposes a large number of tools which exceed typical use of nanoFluidX users. This was clearly a hurdle to a smooth post-processing experience and the nanoFluidX team felt that it needed to be addressed. To that goal, starting with version 2020.1, nanoFluidX install package contains a ParaView Plugin for exposing nanoFluidX post-processing tools.

This Plugin, when enabled, exposes two nanoFluidX-dedicated toolbars and allows for easier post-processing as you no longer need to worry which filters can or should be used, and also conveniently removes the need for filter searching through the drop-down menus.

Starting with the version 5.6, ParaView features Intel OSPRay ray-tracing engine as a part of the default installation. The OSPRay engine in ParaView is conveniently exposed in the filter properties menu. Combined with already powerful and intuitive camera and animation capabilities of ParaView, it is now possible to create high-quality rendered images and videos with tremendous ease.

With ParaView version 5.8, general performance and the OSPRay capabilities have been significantly improved. One example of this is making use of advanced algorithms for denoising so it is now possible to create stunning rendered visuals in under an hour on very modest hardware.

However, one noticeable drawback in the OSPRay application under ParaView is severe lack of material library items which can be assigned to the geometry on screen.

To improve on this issue, nanoFluidX is now shipped with a substantial material library covering various metals, five colors of oil (light, medium, dark, Altair orange and Altair blue) and other colors with matte, glossy or transparent variants. Certainly, it is not on a “dedicated ray-tracing software” level, but it is sufficient for engineering purposes, impressing management, or creating some eye-catching marketing material.