sample: free surface & more

Phicau · October 8, 2011, 16:29

Dear all

I'm currently working with interFoam and so far have been rendering results with paraview. So far, so good but I lack very advanced features of 3D rendering software as Kerkythea, which are able to produce "photorealistic" rendering. Of course I still (and always will) obtain scientific data with paraview, but it is good to have nice videos, because most of the times you sell your work to profane people, which are eager to have eye-appealing results.

Sample utility (or the equivalent function object in controlDict), are able to obtain free surface as a surface (0.5 isosurface of field alpha1), but they lead to "open" solutions since you do not obtain the surfaces below it which are close to the patches/walls. Obviously this is fine and expected, but leads to cases in which data is not ready for a video. For example in a 2D wave flume, the resultant surface is seen as a line when looked from the side.

For such cases paraview has a filter which does what I would like: "clip". It displays alpha1 from 0.5 to 1, which is in fact one or several closed surfaces, surrounding a volume.

Is there a way to use sample to obtain such thing? Or, is there a way to export it in obj from paraview?

Thanks a lot

Pablo H.

akidess · October 11, 2011, 02:59

If you can manage to import VTK data in your renderer, you should have everything in place to make photorealistic animations. I'm not sure of Kerkythea (had never heard of it previously), but there is a VTK import filter for blender:

http://www.ualberta.ca/CNS/RESEARCH/Vis/VTKBlender/

How well it works, I don't know. But please do post here if you manage to produce a nice rendering. Good luck!

Phicau · October 11, 2011, 10:19

Yes sir, Blender is one of the best pieces of software for this purpose, since it is fully scriptable through Python. It has a very steep learning curve, though, and since I have little spare time I've never been able to use it thoroughly, but these days I see clearer that it will be the solution. Now I only have to learn to script a Python filter to match the clip functionality of paraview...

Kerkythea is actually more user friendly, and since I've been using it for a while now I felt comfortable with it. Moreover available materials are awesome. Drawback: it does not support scripts for the things I need, making impossible to make a full video without rendering manually each snapshot.

So thanks, and sure I will post any further progress.

October 8, 2011, 16:29	sample: free surface & more	#1
Phicau Senior Member Pablo Higuera Join Date: Jan 2011 Location: Auckland Posts: 627 Rep Power: 19	Dear all I'm currently working with interFoam and so far have been rendering results with paraview. So far, so good but I lack very advanced features of 3D rendering software as Kerkythea, which are able to produce "photorealistic" rendering. Of course I still (and always will) obtain scientific data with paraview, but it is good to have nice videos, because most of the times you sell your work to profane people, which are eager to have eye-appealing results. Sample utility (or the equivalent function object in controlDict), are able to obtain free surface as a surface (0.5 isosurface of field alpha1), but they lead to "open" solutions since you do not obtain the surfaces below it which are close to the patches/walls. Obviously this is fine and expected, but leads to cases in which data is not ready for a video. For example in a 2D wave flume, the resultant surface is seen as a line when looked from the side. For such cases paraview has a filter which does what I would like: "clip". It displays alpha1 from 0.5 to 1, which is in fact one or several closed surfaces, surrounding a volume. Is there a way to use sample to obtain such thing? Or, is there a way to export it in obj from paraview? Thanks a lot Pablo H.

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October 11, 2011, 02:59		#2
akidess Senior Member Anton Kidess Join Date: May 2009 Location: Germany Posts: 1,377 Rep Power: 29	If you can manage to import VTK data in your renderer, you should have everything in place to make photorealistic animations. I'm not sure of Kerkythea (had never heard of it previously), but there is a VTK import filter for blender: http://www.ualberta.ca/CNS/RESEARCH/Vis/VTKBlender/ How well it works, I don't know. But please do post here if you manage to produce a nice rendering. Good luck!

October 11, 2011, 10:19		#3
Phicau Senior Member Pablo Higuera Join Date: Jan 2011 Location: Auckland Posts: 627 Rep Power: 19	Yes sir, Blender is one of the best pieces of software for this purpose, since it is fully scriptable through Python. It has a very steep learning curve, though, and since I have little spare time I've never been able to use it thoroughly, but these days I see clearer that it will be the solution. Now I only have to learn to script a Python filter to match the clip functionality of paraview... Kerkythea is actually more user friendly, and since I've been using it for a while now I felt comfortable with it. Moreover available materials are awesome. Drawback: it does not support scripts for the things I need, making impossible to make a full video without rendering manually each snapshot. So thanks, and sure I will post any further progress.