Hi, I am trying to simulate a visualisation that portrays Airflow within a building as if it were trails:




I am planning to use Embergen and then export the ABC file to Houdini. I wonder how difficult this is for a beginner? I imagine it is possible, since I still haven't found anything Houdini isn't feasible for.

What do you recommend for a beginner?

Thank you

you have file on qiita web plats , just search on Google "Qiita Advent Houdini 2020" 0r 2021
have Fun.

cncverkstad
Qiita Advent Houdini 2020

I am not sure I am following:

Hi,

You can achieve this entirely in Houdini, either by using its pyro/smoke solvers for more physically based results, or by building a simplified setup with the Linear Solver to generate plausible flow around the buildings.

animatrix_
Hi,

You can achieve this entirely in Houdini, either by using its pyro/smoke solvers for more physically based results, or by building a simplified setup with the Linear Solver to generate plausible flow around the buildings.

Hi. I downloaded a ABC embergen from the library.

Here is the link https://jangafx.com/software/embergen/download/free-vdb-animations [jangafx.com]

Any of those will help as a reference.

So I am not looking to sim in Houdini. Just to achieve the trails of the sim to convert them to curves.

Thank you

I started doing this:





I checked that there is a volume to the trail node. Is it possible that the Alembic is missing the Vel attribute, which is needed to trace the lines?

Thank you

I checked one of the caches and it doesn’t include a velocity field. You can approximate velocity by using Volume Optical Flow SOP between two consecutive caches.

animatrix_
I checked one of the caches and it doesn’t include a velocity field. You can approximate velocity by using Volume Optical Flow SOP between two consecutive caches.

Image Not Found

Image Not Found

Thanks a lot for this. Is it possible to share the scene? Since I am new doing this I am trying to understand the use of the timeshift. Also what do you call cashe sice I do not see the nodes applied in the screen grab.

Thanks again!

I am trying to replicate your setup.




But I am clearly missing something to get the trails. How did you generate the vel attribute?

Thank you

Here is the scene.

animatrix_
Here is the scene.

Hi. Thank you for this. I think I have a bit better understanding now. But lines seem not to be coinciding with the smoke shapewise.
Is this something expected? Thank you

Unfortunately without the original velocity field, there isn't much you can do.

animatrix_
Unfortunately, without the original velocity field, there isn't much you can do.

Ah, I did not know that was needed to align them. I will check if it's an attribute that can be exported from Embergen.

Thank you

I am not sure I am following:

on qiita web plats advent Houdini 2020 , user @shin_t_o_
file "city wind generator" . 2d 3d SIM.
Find user and check Link to the Github