# ? Thin Wispy Layers of Fog or Smoke?

I need to get thin wispy fog or smoke spread out in layers or lines. Like the layers of fog one sometimes see forming in a forest. Or smoke where a very slight wind is moving the smoke around objects such as trees.

I understand the tight colour ramp with mostly transparent to get the thin wisps. My problem is with the particle physics and smoke flow.

I tried having moving particles going along trailing smoke. The particles still emitted the smoke in a spherical manner. Force fields such as wind or vortex did not stretch the wisps out like I need.

I then thought of having an emitter plane off camera with a collision mesh just in front of it. The collision mesh would have random holes cut in it for the smoke to pass through. Vorticity of the smoke passing through the holes should give me the sort of streaks I want.

Then I ran into smoke velocity problems. If I turn on physics for the emitter particles, they collide with the mesh and then move through the holes. But as soon as the particles are through the holes they go back to emitting smoke in a sphere as above.

So I thought to turn off physics for the particles so they would stay at the emitter mesh. But then I run into a problem with the smoke having no initial velocity to pass through the collision mesh. I look at the smoke flow and in the settings there the smoke initial velocity seems to be based on the velocity of the particles. Which is now zero.

I tried getting rid of particles altogether and changing the smoke flow to be emitted direct from the emitter mesh. But when I try to find documentation on the relatively new capability of meshes to emit smoke directly, it appears to say the initial velocity of the smoke is based on the velocity of the mesh. The mesh is not moving. So I do not understand this.

Can anyone give me some suggestions how to do this? Or tutorials which might show something similar?

The inkdrop tutorial from BlenderDiplom taught me quite a bit about how to get the wisps. But I can not seem to modify those ideas to stretch the wisps out into layers. The various tornado and wind tutorials I have found so far seem to result in the heavy smoke spherical blob sort of thing - not thin wisps drawn out into layers.

Started experimenting using version 2.65.