Rendering your CFD results - general discussion
 

Hello fellow numericists!

I'm trying to get a discussion going about how to render your cfd results in an easy and efficient way...I'm wondering if there are people out there who have experience in rendering their solutions with a professional (although free) rendering tool like blender or povanimate..... I've been trying to read up on how to actually render my stuff, but I cant make heads or tails of it :)=

So, if there are guys and galls out there who would be interested in discussing rendering for numericists, maybe setting up tutorials and creating a webpage for the community, please reply!

so long, take care y'all!

cfd noob

Hi,

Do you (after one year) already have a clue how to tackle this problem? I'd be interested in any information or tips that you might have!

Regards,

Ralph

Hello,
Yes, I have in the meantime set up a rendering toolchain for our cfd solver that uses blender to create some nice animations. It does still require some more time then lets say create a simple still picture in tecplot, but of course it looks way better!
I havemt tried povray or any other remdering tool, i find blender does all I need.
All the best,
Newbie

Thanks for your reply. Yesterday evening I also found some links pointing in the direction of Blender. It seems that a VRML export of the data from paraFoam can be imported and rendered in Blender directly?
Do you know a tutorial which you find very useful?
Thanks!
Ralph

Hello Ralph,
the way I did it was to search google for "paraview blender", since I'm using paraview for postprocessing. paraview can export x3d files, which blender can read. It is pretty easy to just import a single geomtry and render it, however, if you want to do time dependent stuff, you will have to do quite some scripting! But the vids look indeed very nice, I think, here's one from youtube I like:
http://www.youtube.com/watch?v=0aACFaRazuA

Cheers,
newbie

Yep, you are right: http://www.openfoamworkshop.org/6th_...gun_slides.pdf

Hopefully the next OF user who is looking for this stuff doesn't has to spend an evening browsing the web ;)

Thanks for your help!

Wow, great slides, thanks Ralph. If I had had these 6 months ago, I wouldn't have had to invest so much time in scripting python... but that's how you learn :)

Be very careful though when using "older" scripts for blender 2.63 and above. I wrote my scripts for 2.62, and found that some stuff didn't work in 2.63a and I had to rework quite some things. But it worked in the end....

If you need any more help, let me know!

Newbie

as a side note: hmmm...maybe I should write up my stuff, make some nice screenshots and post them all online as a tutorial...

http://www.youtube.com/watch?v=5-GtdRLfeFI

found it: here's the vid that helped me do the first rendering!

Thanks! I will have a look into this later today.

Hey Ralph,
just wondering: did you get your rendering done?
Cheers
cfd newbie

Good morning CFD Newbie,

Yes I managed to create some fancy renders. It's extremely difficult to render water (for multiphase flows with a ship) but once you got the settings right it works like a charm!

Attached you find one of the first renders that I made (altough I can make better ones now :)) .

Regards,

Ralph

Hello Ralph,
looks great! glad it worked out for you. I'm working on setting up a website with some hints on how to render CFD results in blender. I'm sure there are more people out there who would like to give it a try. plus it looks so much better than tecplot :)

keep blending :)
cfd newbie

Hi guys.
Your results look awesome. Can you please give us a clue how you created them. Specially, the transient ones! A tutorial would be a great idea!
Thanks, Soroush

Why not use Paraview?
 

Hi

Using Blender might be an option, but what is the problem with just creating the animations with Paraview itself? Paraview can open multiple files at once and animate the visualization at your convenience. You can very easily export frames of the animation with the dedicated functionality and create videos easily. If you are using OpenFOAM the tool paraFoam opens up the solution right the way you want but I am sure an easy solution exists for all major CFD tools.

Yeah, of course, animation in paraview is a lot easier, but the rendering with a professional render engine just looks a lot nicer! Plus you can do easy camera movement, POVs, textures, lighting etc!

Exactly, As a matter of fact, We are currently using Ensight for post processing and creating animations and it does its job great, even different types of camera movements are available. but that is not wat I want exactly!

I am not very familiar with Paraview and Blender. But I worked with Autodesk Maya for some years and I know the potential of a professional software like Blender for post-processing.

Honestly, I was going to import my data into Maya first through MEL, but it is very complicated, since I couldn't even import X3d files into it. But it seems that Blender can do the job more easily.

Anyway, Can you guys help me where to start?
I am learning Blender right now, But I think I should learn a bit of Pyton scripting as well. Can you suggest me a reference for that?

Thanks,
Soroush

Soroush,
here you will find the complete python script used in the blender python console to do the animations, i.e. read in the x3d files and do the videos in the thread:

http://www.blender.org/forum/viewtopic.php?t=23052

I havent been able to clean it up or write a concise tutorial due to time constraints, but if you have any additional questions, just let me know!


the toolchain should be like this:
1) export the geometry/solution as x3d from paraview
2) import it into blender
3) setup your camera, lights, animations
4) render the movie


The script does 2) and 4), in between, you have to setup the camera, lights etc in blender, save it as a blend file, and then execute blender with the python script!

Thanks for the information,

Just one thing: what was the version of your Blender and Paraview when posting in that froum? I'm not sure, but I think scripts are a little version dependence, right?

Blender was either 2.63a or 2.63, dont remember....
Paraview was 3.14.1

OK, Great,
Thanks