Very small job: help me learn to do a task in Paraview (ParticlePath, ParticleTracer)

SFr · July 23, 2016, 05:10

I have posted this as a question, but haven't received any replies. Maybe someone would be interested in helping as a small job. Please feel free to let me know if I'm not being clear about what I want.

I am using OpenFOAM to simulate fluid flow out of tanks and I'm plotting the results in Paraview. For weeks now, I have been trying to figure out how to see what happens to fluid that is initially along a horizontal line half way down the tank. During flow out of the tank, it should become deformed.

The only way I can think of to do this in Paraview is to use the "ParticleTracer" and "ParticlePath" filters. However, when I try to use them, I end up with only a blank screen. I have searched extensively online and have seen a couple of comments by people who have had a similar problem, but I don't see any solutions. So I'd like someone to help me figure out where I'm going wrong or offer an alternative method of doing what I want to do.

Here's what I'm doing. First I go to Paraview's "Sources" menu. I choose either "Plane" or "Line" or even "Point Source." But then when I invoke the "ParticleTracer" or "ParticlePath" filters, I get a blank screen. I have tried changing all the settings I can think of--for example, representing the results as glyphs, surfaces, etc. Nothing has worked.

I am using Paraview version 5 and Ubuntu 16.04, but I had the same problem when using Paraview 4 versions and Ubuntu 14.04. My budget is about 30 Euros.

crixman · July 23, 2016, 07:15

Hi, I think you need to apply the Clip -> scalar filter selecting alpha as variable with value 0.5 (the range should be 0 to 1).
The fluid interface should be at a value of 0.5 - if the fluid is between 0.5 and 1, leave it as is, if from 0 to 0.5, tick below the inside out box.
Let me know if that solves the problem.
Christian

SFr · July 23, 2016, 08:13

Hi Crixman, thanks for your response.

This looks promising, but there's something I don't understand. Apologies in advance for what is probably a silly question.

I think "Value" for Clip is based on colour somehow, but can't figure out how. This is an issue because I have two different types of simulation: (1) two layers of fluid (different colours) and (2) just one type of fluid (one colour)...

When I am dealing with two layers of fluid and want to pick a line somewhere in the tank to track, I can pick any "Value" for Clip below 1 and the result is always the interface between the two fluid layers. When I pick a value above 1, the clip disappears and there's a blank screen. When there's just one fluid layer, I'm getting a blank screen.

Do you have any idea where I'm going wrong? Thanks very much. P.S. if this works, PM me and I'll send the money your way!

crixman · July 26, 2016, 17:14

Hi,
it's not based on colors, it's based on the range of the variable - you need to select the variable and then rescale the range with the button on the right of the value.
Let me know if that works!
Christian

SFr · July 29, 2016, 08:56

Hi Crixman, thanks. Sorry for the late reply, I didn't see the notification. I have figured out how it works in general, but unfortunately, it's still not working for me.

I have X-Y plots of various variables. My problem is that I want to draw a horizontal line at time = 0, then track that over time. If I understand how Clip works now, I don't think it's possible to do that. I can pick a particular variable value (like concentration) and track that, but I can't pick a particular line or plane in X-Y space and track it.

July 23, 2016, 05:10	Very small job: help me learn to do a task in Paraview (ParticlePath, ParticleTracer)	#1
SFr New Member Join Date: May 2016 Posts: 19 Rep Power: 10	I have posted this as a question, but haven't received any replies. Maybe someone would be interested in helping as a small job. Please feel free to let me know if I'm not being clear about what I want. I am using OpenFOAM to simulate fluid flow out of tanks and I'm plotting the results in Paraview. For weeks now, I have been trying to figure out how to see what happens to fluid that is initially along a horizontal line half way down the tank. During flow out of the tank, it should become deformed. The only way I can think of to do this in Paraview is to use the "ParticleTracer" and "ParticlePath" filters. However, when I try to use them, I end up with only a blank screen. I have searched extensively online and have seen a couple of comments by people who have had a similar problem, but I don't see any solutions. So I'd like someone to help me figure out where I'm going wrong or offer an alternative method of doing what I want to do. Here's what I'm doing. First I go to Paraview's "Sources" menu. I choose either "Plane" or "Line" or even "Point Source." But then when I invoke the "ParticleTracer" or "ParticlePath" filters, I get a blank screen. I have tried changing all the settings I can think of--for example, representing the results as glyphs, surfaces, etc. Nothing has worked. I am using Paraview version 5 and Ubuntu 16.04, but I had the same problem when using Paraview 4 versions and Ubuntu 14.04. My budget is about 30 Euros.

July 23, 2016, 08:13		#3
SFr New Member Join Date: May 2016 Posts: 19 Rep Power: 10	Hi Crixman, thanks for your response. This looks promising, but there's something I don't understand. Apologies in advance for what is probably a silly question. I think "Value" for Clip is based on colour somehow, but can't figure out how. This is an issue because I have two different types of simulation: (1) two layers of fluid (different colours) and (2) just one type of fluid (one colour)... When I am dealing with two layers of fluid and want to pick a line somewhere in the tank to track, I can pick any "Value" for Clip below 1 and the result is always the interface between the two fluid layers. When I pick a value above 1, the clip disappears and there's a blank screen. When there's just one fluid layer, I'm getting a blank screen. Do you have any idea where I'm going wrong? Thanks very much. P.S. if this works, PM me and I'll send the money your way! Last edited by SFr; July 23, 2016 at 08:28. Reason: Clarification

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July 23, 2016, 07:15		#2
crixman Member Christian Join Date: Apr 2014 Posts: 74 Rep Power: 12	Hi, I think you need to apply the Clip -> scalar filter selecting alpha as variable with value 0.5 (the range should be 0 to 1). The fluid interface should be at a value of 0.5 - if the fluid is between 0.5 and 1, leave it as is, if from 0 to 0.5, tick below the inside out box. Let me know if that solves the problem. Christian

July 26, 2016, 17:14		#4
crixman Member Christian Join Date: Apr 2014 Posts: 74 Rep Power: 12	Hi, it's not based on colors, it's based on the range of the variable - you need to select the variable and then rescale the range with the button on the right of the value. Let me know if that works! Christian

July 29, 2016, 08:56		#5
SFr New Member Join Date: May 2016 Posts: 19 Rep Power: 10	Hi Crixman, thanks. Sorry for the late reply, I didn't see the notification. I have figured out how it works in general, but unfortunately, it's still not working for me. I have X-Y plots of various variables. My problem is that I want to draw a horizontal line at time = 0, then track that over time. If I understand how Clip works now, I don't think it's possible to do that. I can pick a particular variable value (like concentration) and track that, but I can't pick a particular line or plane in X-Y space and track it.