[UE4][Niagara][Houdini] Need help creating a global wind vector field

As I said in the title I’m trying to build what is essentially a way for particles to move around mountains in our landscape. I want to do this by making a wind force vector field in Houdini. Currently I’ve got a few steps outlined but I’m getting stuck in a few places.
Stages:

  1. Run a simulation over the landscape
  2. Saved the velocity of that simulation to a velocity field
  3. Reference that vector field in the Niagara particle systems

With step 1 I’ve tried using a particle sim and a pyro sim to get the vector field that I want. I haven’t figured out how to get the stimulant to run around the geometry only through it. I found this video that outlines what I’m trying to achieve but they don’t go in depth on how they achieved the results:

With Step 2 I’ve looked at a few online tutorials to see how they managed to get a vector field and their visualizations always look a lot different to what I’m getting out. Instead of the long strands I only seem to get tiny lines like so:

With step 3 I’ve managed to get the particles doing something with the outputted vector field but I don’t have a way of visualizing it so I have no idea if the fields in the right location, pointed in the right direction or is the right size.

Does anyone know how I can fix the issues I’m having?

Made some progress with steps 1 and 2!

Major issue I was facing was collision not working right which was caused by my landscape being a thin sheet. Fixed by extruding the edges, merging a cube on the bottom, VDBing it then converting it back to polys to “dynamesh” it. Now that’s working I have particles flying over the surface as I’d expect.

Step 2s issue was due to the landscape being landscape size which is too big for a lot of Houdini features to handle. at first I shrunk it down by a factor of 100, and then shrunk it down to a further 0.085 of that. Now I’m getting the strands I’m looking for.

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looks like a great effect to learn from, can’t wait to see what the results are!