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Freeman February 19, 2006 13:01

Paraview Questions
Hi all!

I've done some 3D simulations with Fluent of the flow over a car and now I want to visualize the results with Paraview. There is very little documentation in the net: I've only found the Paraview v1.5 User's Guide (I am using the latest, v2.4) and it is not very self-explanatory.

What I do is export in Fluent the results of the simulation as Enview format and I open it in Paraview with the Enview translator with the "little endian" option enhabled. What I want know is to visualize only the part of the whole mesh that is the surface of the car in order to make later other contour plots, streamlines, etc. over this surface mesh. Is there any option to "extract" from the whole mesh this surface mesh of the car?

And another thing: is it possible to make screenshots and save them as jpeg or so? What is the command?

Thanks a lot!

Renato. February 19, 2006 13:22

Re: Paraview Questions
You can do whatever you've cited in your post.

first: To extract the body surface of your car, apply the "extrat surface" filter (this filter will give you the external boundary mesh of your model), then, use the "clip" filter in order to clip only the body car.

second: To make movies and screenshots you just need to use the "view/keyframe animation" menu item.

PV does not offer any user's guides because Kitware earn money selling their books and courses, but a good starting point for you would be the Paraview's maillist. There are many people contributing to this list answering questions like yours.



Freeman February 19, 2006 16:19

Re: Paraview Questions
Thanks a lot Renato: that was a quick and effective reply! I've been successful in extracting my surface mesh of the car and now I know how to take pictures.

But I have another question: as my simulation was done with a symmetry plane, is it possible to make a symetry of my plots in Paraview? I don't see the filer used to make this if it is possible... by the way, if it were possible, would it be possible to erase that symetry plane or simply I have to clip a bit the box what I used to make my surface mesh in order not to let that symetry plane to appear?

Thank you for your advice.

Renato. February 19, 2006 17:05

Re: Paraview Questions
Yes, there's a filter called "reflection" just to make an entire representation from symmetric models. Regarding the symmetry plane, you're at the right way... you'll need to clip the symmetry plane a bit in order to get a clean image of the reflected object.

take a look in the following images I've done:

they were produced with Paraview from a half modeled car. I suppose it's just what you want to do in your model ;-)



NOTE: PV 2.4 has some bugs regarding filter association for some readers, so, if the "reflection" filter is not enabled to apply in your model, try the same think in previous versions of PV, such as 2.2.1

Charles February 19, 2006 17:06

Re: Paraview Questions
First, in order to extract the surfaces, the easiest way is to use Filter-Extract Datasets, particularly if you named your surfaces. Here you can decide, for example, to extract the floor and the half car, but not the plane of symmetry. When you do this, your original data set is blanked, but not erased, so you can do more operations on it later.

To make symmetry, select your extracted surfaces in the selection window, and run the filter Transform, on these surfaces, setting the y-scale to -1. When you accept this, it will transform your half model to the other side, but you are still stuck with half a model.

So now run Filter-Extract Datasets on the original data set, to create another half model, so now you have a full model with no symmetry plane.

No doubt somebody will point out a more elegant way of doing it, but this works too.

Charles February 19, 2006 17:14

Re: Paraview Questions
Ensight files written by FLuent don't seem to allow "reflection" in 2.4. I had to go back to check why I was using such an elaborate method!

Freeman February 20, 2006 14:15

Re: Paraview Questions
Thanks a lot, Renato and Charles.

Charles, this Extract Dataset is what I was also looking for, because in Fluent I defined my model in different sub-surfaces: with this filter, selecting my different surfaces is now as easy as it is in Fluent.

Playing a little with Paraview I've realized that I don't understand the use of the glyphs and even I don't know how to represent a vector field like the flow's velocity. I imagine that somewhere I can activate this vector field and then, I have to mask this filed with an arrow or cone glyph in order to visualize it, but I don't understand the "philosophy" of the method. Can anybody of you shed me some light to this? (To make vector fields and how to use the glyphs cleverly)

Many thanks for your kind help!

Regards, Freeman

Charles February 20, 2006 16:51

Re: Paraview Questions
I'm far from a glyph master, but at least getting vectors is easy. Starting from your initial data set, you can run a filter to get a surface, typically something like a plane, but it could also be an iso-surface, etc. Once you've got a surface, use that as your active data set and hit the vector (glyph) button, and you should get vectors distributed on that surface.

Now, if somebody could tell me how to do "oil-flow" traces on a surface it would be really nice!

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