Wind Tunnel / Vector Field Masking

[AsgerMortensen]

Hi, I love the "wind tunnel direction" feature in the sparse solver, and I would like to find a way to mask it's effect.
I know this is just a vector field node with "External Direction" set to a given value, but I don't know how to apply a mask to it (say I'm simulating a chimney with smoke rising out from the top. I wouldn't want the wind inside my chimney).

I can do this inside the gas wind node or with any other force node. The problem is: none of them look nearly as good as the "External Direction" option in the vector field node! (with gas wind being the worst).

I've tried using the "Sop Vector Field" node, and plugging in a sop field with the same value to what an "External Direction" value might be. It kinda works, but not quite. The result is not the same, and I noticed that the velocity field is getting incorrectly updated. (it flashes in and out of active areas when "activated") - also it's slower 

I hope there is a Gas DOP expert who can help me. Basically what I want, is a wind that looks as natural as the "Wind Tunnel / External Direction" but with the ability for applying masking (and other stuff if possible).

Thank you so much, if you actually read this. Thank you even more, if you can help 

Best Regards, Asger Mortensen.

[bunker]

wind tunnel direction is on the smoke object. it sets the velocity on the boundary of the vel field.
so no, you cannot mask that.

 

[bunker]

if you really want to use the wind tunnel direction,
you could try cancelling the wind velocity inside the chimney for example.
 

Edited April 14, 2021 by bunker

[bunker]

windtunnelmask.hip