## New user using value blanking

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darkfall13
Newbie
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Joined: Tue Jun 29, 2010 1:40 pm
Location: USA
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### New user using value blanking

Hello! I've been using Tecplot for the past few days at work but I've been asked to do something that doesn't seem to be readily obvious to me. I've got a scatter plot and the points are colored using multi against a 3rd variable. The contour levels have been defined to run from -50 to 50 but my boss wants to see how the extremes are clumped and wants me to cut out the -10 to 10 range.

Value blanking can meet part of that request. ie blank when variable is less than or equal to 10, but then that blanks out everything below 10, you can't set a lower bound and likewise for the other direction.

So is there a way to get the program to just blank out a specified interval of the data?

Another suggestion by someone in the department (though unfamiliar with Tecplot) is to break the plot into bins and average the values in the bins because it'll get rid of all the overlapping so can Tecplot do this?

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Tecplot Version: 9.2-0-3 (Sep 18 2002)

chai13
Experienced user
Posts: 12
Joined: Fri Jun 14, 2013 1:49 pm
Location: Corvallis, OR

### Re: New user using value blanking

Hi,

Did you ever find the solution to this problem? I am trying to do the same. Would appreciate if you can help.

thanks

salter
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Joined: Thu Dec 21, 2006 10:57 am
Location: NASA Langley Research Center
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### Re: New user using value blanking

You can always blank according to a variable that is either 0 or 1. In this case, you want to write an equation that computes a conditional that would result in a point having a value of 0 or 1, using the equations editor. A sample equation may look like the following:

Code: Select all

`{BlankVar}=(sign(abs(v4)-10.00001) + 1)/2`

In the truth tables, this will produce a 0 for points that have a value of variable 4 greater than -10.00001 and less than 10.00001. All other values will be 1. Then set your blanking to that variable, and all points that have values between -10.00001 and 10.00001 will be gone. Note that I used something slightly higher than 10 because if you use 10, those with values exactly 10 will still be shown.

Good Luck.
Steve...

Aerospace Research Engineer
Aerothermodynamics Branch
NASA Langley Research Center

chai13
Experienced user
Posts: 12
Joined: Fri Jun 14, 2013 1:49 pm
Location: Corvallis, OR

### Re: New user using value blanking

Thanks a lot! This helps ...

Btw can we not use this approach for blanking the isosurfaces? I am trying to visualize near wall structures in turbulent boundary layer (lambda-2 variable) and I would like to see structures which has certain lambda-2 value. But somehow blanking is not working with iso-surfaces..... any suggestions?

thanks again ..

salter
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Joined: Thu Dec 21, 2006 10:57 am
Location: NASA Langley Research Center
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### Re: New user using value blanking

Can you be a bit more specific about iso-surfaces? If you are looking for specific iso-surfaces, you can produce them by using a specific lambda-2 value. So I'm unsure I understand what you are requesting.
Steve...

Aerospace Research Engineer

Aerothermodynamics Branch

NASA Langley Research Center

chai13
Experienced user
Posts: 12
Joined: Fri Jun 14, 2013 1:49 pm
Location: Corvallis, OR

### Re: New user using value blanking

Yes, sorry for the confusion. I have a variable lambda-2 and I can create an isosurface using that variable. But I would like to know if I can somehow visualize isosurfaces for "range" of labmda-2 values instead of a single value.

I also wanted to visualize lambda-2 isosurface at specific x,y,z location (which I was trying to get using blanking option). But it seems to me that blanking does not work with isosurfaces. Is there any workaround?

salter
Moderator
Posts: 188
Joined: Thu Dec 21, 2006 10:57 am
Location: NASA Langley Research Center
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### Re: New user using value blanking

To blank a specific place on an iso-surface. you must first extract the iso-surface as a zone. Then you can do what you want with the display of the data. To look at a range though, there should be an upper and lower bound for iso-surfaces. Which version of Tecplot are you using?
Steve...

Aerospace Research Engineer

Aerothermodynamics Branch

NASA Langley Research Center

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