copyfert.blogg.se - Paraview resample with dataset

#PARAVIEW RESAMPLE WITH DATASET INSTALL#

One of the great pleasures of working with OpenFOAM is the joy of figuring stuff out.

#PARAVIEW RESAMPLE WITH DATASET INSTALL#

Is it as nice as having a custom-built tool? Nope.īut…it’s quick, it’s easily scripted, there are no new tools to install or maintain & the output looks great – I’ll take it.ĭrop me a note if you want details about the actual commands & dictionaries involved. Export the surfaces &/or post-process your changed/target case as normal – now with delta flow fields 🤩.

Use mapFields to subtract the baseline/source fields from the changed/target fields, leaving you with a delta for each of the variables in your case.

Rinse & Repeat in your changed/target case.

Reconstruct this new little mesh & the data (this isn’t strictly necessary, but it speeds up mapFields, later on).

Subset your volume mesh – subSetMesh– so that only those selected cells remain (don’t use -overwrite 😬).

Use topoSet to select the cells that border the surfaces you’re interested in, using its patchToSet action.

Delta = Changed – Baseline = Target – Source.

A Changed case that will be your Target.

A Baseline case that will be your Source.

Choose two solved cases (they can have different volume meshes).

So, I tweaked the workflow to give it less to do & now your deltas will be done & dusted before the kettle’s even boiled. A bit much if you just want surface deltas. You can make (& drink) several cups of tea while it crawls over your whole volume. But it’s super-slow on a “big” mesh (whatever “big” means). Think, transferring the results from a coarse-mesh onto a finer-mesh, to be used as the starting point for a new run. The mapFields utility in OpenFOAM is intended (AFAIK) to be a PRE-processing tool, used to map results from one mesh to another. I always ended up with lots of faces that couldn’t be matched & very blotchy-looking plots. You can get pretty close using ParaView, combining the Resample with Dataset & Append Attributes filters, but I never got great results. It’s not restricted to surfaces, you can also do it with volumes. It’s a useful alternative to playing spot-the-difference with two almost identical plots 🧐 I’m guessing you already know, but just in case – a delta plot takes common(ish) surfaces from two different cases, calculates the difference between their two flow fields & uses this “delta” to illustrate where the flow has changed.

One of the most elusive was “the delta plot”. Some things were rendered obsolete by new OpenFOAM functionality. Duct taping standard OpenFOAM/ParaView/Unix tools together in new & imaginative ways was (& still is) the order of the day. I’m not a developer, so rolling my own versions of those tools wasn’t quite so magical. Admittedly, some things were more useful than others, but nevertheless, it was still like magic.įast-forward to me going solo. We had a small team of developers who could conjure up new CFD tools as if by magic. I figured something out, something that’s been niggling me for a decade & I’m going to tell you about it…1) ‘cos I’m super-happy that I figured it out & 2) ‘cos that’s what this email is all about – sharing stuff that you might find useful. You know when people show you their baby/pet/baking pictures & you have to respond like it’s the cutest/cleverest/tastiest little specimen you ever did see? Well, this email is just like that. I want to share a little CFD win this week – delta plots – let’s go… And the Gaussian blur module in Slicer doesn’t allow one to select a “model” as input.It’s Robin from CFD Engine, back with your weekly CFD note. vtk file, I can’t seem to import it as a “volume”. However, the problem here, is that since my present data is generated at the source as a. DICOM files, I just import as a “volume” and can use the Gaussian blur module to blur the image. You’re absolutely right, I can ideally do everything I need to do in Slicer. Specifically, I want to apply a Gaussian blur to the volume, to simulate the same data imaged at different resolutions. Sure the program I’m using creates voxel data output as cells in a.