best practice for CFD simulation rendering

[fraggle]

Hello, what are you advice regarding this type of simulation rendering:
https://youtu.be/F5Lu_aRj5M8

I can get the simulation done from CFD specialist that used CFD software (like Ansys Fluid...).
But then, will it be possible to reuse this simulation to render it with vray?

Or should I start from scratch and make the simulation inside max? Of course it won't be as accurate as the one from CFD software I guess.

Thanks

[yolov]

That's a good question. It could be possible if Ansys can export vdb files and then render them with the V-Ray Volume Grid. We could check if that's possible.
Or you could give it a try with PhoenixFD

[fraggle]

Thanks, but PhoenixFD demo version won't let me handle such complex simulation I guess.

I will look for the answer regarding VDB file format export from CFD software.

Thanks

[yolov]

As far as we could understand from the Ansys documentation, it doesn't support export to vdb. But you can ask your artist what type of formats it supports.
As for the PhoenixFD Demo - yes, it has limitations, but you could ask for a full evaluation copy by dropping a line to sales@chaosgroup.com

[fraggle]

What kind of CFD software can export vdb format? Will be better to approach the problem this way, then after only, look for the freelancer with such software to make the CFD.
Thanks.

[yolov]

That should be up to the Software being used to be capable of exporting to such formats.
In my last post it was just the conclusion that I might have wrongfully made that you already had someone working with such software and knowing its capabilities. Sorry if I have mislead you in any way.

I can get the simulation done from CFD specialist that used CFD software (like Ansys Fluid...).
Thanks

[fraggle]

Thanks, I tried on google buth CFD + VDB export lead to zero result. Matlab, Ansys... none of this CFD software support the Open VDB or F3D format. That's weird!

[fraggle]

I got a feedback from https://www.simscale.com/ support. According to them they are able to get their simulation out to http://www.paraview.org/, then from Paraview to blender for the rendering.
If blender can do it I believed that Vray and max can do it!

here are the list of CFD code (i guess it correspond to imported code, not the exported one)
http://www.paraview.org/fluid-dynamics/

As for export, thereafter are the paragraph about it:
"8.2.2 Exporting scenes
When available, you can export a visualization in a view in several of the supported formats using the File Export View
menu option in paraview. For a Render View (or similar), the available formats include EPS, PDF, PS, SVG, POV,
VRML, WebGL, X3D, and X3DB. On selecting a file as which to export, paraview may pop up an Export Options
dialog that allows you to set up parameters for the exporter, similar to saving datasets (Section 8.1).
In addition, from paraview, exporting takes the following form (again, just use Python trace to figure out the proper form
– that’s the easiest way).
1 >>> myview = GetActiveView ()
2 >>> ExportView(’/tmp/sample.svg’, view=myview ,
3 Plottitle=’ParaView GL2PS Export ’,
4 Compressoutputfile =1)
5 # the arguments after ’view’ depend on the exporter selected."

Thanks

[Svetlin.Nikolov]

Yup, I guess at least some of these formats could be easy to implement import from.

However, it seems like a pretty low-res simulation that you should be able to do even with a Phoenix demo. If you have any questions or issues on the Phoenix side, please drop some lines in the Phoenix forums and we'll be happy to help.

Cheers,

[fraggle]

wait, I'm confused know. PhonixHD is just a graphic simulation it can't be used as a solver? There is plenty of parameters I guess, like friction, load loss...such parameters can't be implemented into phoenix, so the solution will be wrong.

By low res simulation, what do you mean exactly? It is inaccurate?

[Svetlin.Nikolov]

Well, Phoenix is a fluid dynamics solver and shader. It's oriented towards VFX, but that doesn't mean it entirely fakes its results and is inaccurate - like all CFD solvers you can choose how precise the results are, which is a tradeoff between simulation time and quality. The current state of scientific progress on CFD is pretty low in my personal opinion and the same numerical approximations are used in both Phoenix and the responsible industrial CFD solvers. Of course, you should not use Phoenix for solutions that would decide people's lives, or for supersonic fluids which go by different laws, but the reference video is something that is easily achievable with Phoenix - all the visible aspects of it at least. If you need it for visualization purposes, I think you should give it a shot

[Raven]

I did a quick test of a 1.6 mil cell grid. If I remember correctly the demo can go up to 2 million.
Works pretty well I would say.

[fraggle]

Thanks Raven for the test.
I will give it a try, thanks Raven.
Svetlin, the version 3 is only for max 2017 in the download section but I'm staked to 2016.
Seems that the v3 is easier to work with. Is there a v3 in the nighties build in demo mode?

Thanks

[fraggle]

Can you limit/measure with phoenixFD the quantity of water dropping into the sink? let say 0,2l per second....

I did a quick test of a 1.6 mil cell grid. If I remember correctly the demo can go up to 2 million.
Works pretty well I would say.

[Svetlin.Nikolov]

Ah, dang, there was some maintenance on the download section of the website and seems like the builds for 2016 are not visible now. They are there, but we have to wait for the admins to come back tomorrow...

Here's the Max 2016 demo for 3.00.02 on Google Drive: https://drive.google.com/open?id=0B6...TYxQ3JocTVvQnM

There are nightly builds too, which contain all the latest additions and bug fixes, which are available for anyone with a license.

Hope this helps, cheers