Voxels from expression

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Al Greynolds

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Apr 30, 2021, 9:22:50 AM4/30/21
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Can the new voxels capability display an isosurface of an expression, i.e. a given function of x,y,z?

Al

Gavin Buxton

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Apr 30, 2021, 10:08:54 AM4/30/21
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On Friday, April 30, 2021 at 9:22:50 AM UTC-4, Al Greynolds wrote:
> Can the new voxels capability display an isosurface of an expression, i.e. a given function of x,y,z?
>
> Al

Apparently so....

https://lwn.net/Articles/828761/

although I've not played around with it. Looks awesome though!

Al Greynolds

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Apr 30, 2021, 11:40:35 AM4/30/21
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Here's what I'm trying to do:

R=1
L=8
n=2
h=3
m=3
f(x,y,z)=x**2+(y-h*(z/L)**m)**2-(R*(1-(z/L)**n))**2
set vgrid $wh size 100
set vxrange [-R:R]
set vyrange [-R:h+R]
set vzrange [0:L]
vfill ?
splot $wh w isosurface level 0

Why does vfill require a file or datablock as a source? Why can''t my function f be used as easily as plot and splot allow plotting expressions/functions instead of files or datablocks?

Al

Gavin Buxton

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May 1, 2021, 10:02:13 AM5/1/21
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Hopefully someone else can help, but you used to be able to set terminal as 'table' and output functions to a file. Assuming videos requires discrete points. Hopefully someone has more experience with voxels. Thanks for asking the question though, as I didn't this was a new feature!

Al Greynolds

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May 4, 2021, 9:59:40 AM5/4/21
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OK I sort of got what i wanted, but had to begrudgingly resort to separately creating a file of point data for vfill. However, even though all inputs are symmetric about the x=0 plane, the resulting isosurface is not. I can provide the script and data files if anyones interested.

Al
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