Rotor/Wind sim on instanced geometry

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sant0s
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Rotor/Wind sim on instanced geometry

Post by sant0s » 19 Jan 2018, 19:06

Hey all, me again :D

I was just testing the super cool "Instances to Geo"-Compounds from the mootzoid plugins and build a grassfield.

Next test was to create a simulation on that geo, to get something like rotor balde wind on the grass.

Actually, it works already quite well.
I used a sphere to get the distance bewteen the emitter grid and the sphere itself.
Than I used the distance value to get a weight map on the grass geometry, to control the power of the "Surface Force"-Compound.

Actually the first 15-20 frames look cool, than it becomes kinda silly when the rotor moves...

Does anyone have some ideas, how to make it more realistic?
I also thought about Syflex - but first that would be a massive sim and second somehow I dont get nice turbulence in the Syflex Forces.
It does not work with the normal "Turbulize around Values"-Compunds etc...

And of course some grass parts, dust, flying debris will make it more cool.

Rendered in Redshift, ~40 seks per frame in HD Ready on a 1080er.

Thx,
sant0s :)

Last edited by sant0s on 26 Jan 2018, 21:03, edited 1 time in total.

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rray
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Re: Rotor Wind sim on geometry

Post by rray » 19 Jan 2018, 19:54

Heyy, Looks great :) Ideas hmmm.. the air seems too well-behaved maybe, some occasional turbulences flying away outward from the center might help with it
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

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sant0s
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Re: Rotor Wind sim on geometry

Post by sant0s » 19 Jan 2018, 22:52

hey rray :)

thx!

I thought also, to create wind with particles.
Like a rotor blade that emits particles and these particles than control the turbulence and bend direction of the grass.
That would give super much control and more variations (speed, votex, etc.).
Maybe Ill try to combine that with emFluid, I think I can use the velocity somehow to deform the gras.

The mbFeaters plugin has these particle wind as far as I remember.
Points are shot on the feathers and generate a nice and realistic wind flow to the feathers.
Have to try that again, too.

edit:
something else I try without use of heavy sim, is these wind flowing over a field.
Did not find a video on youtube yet - but its like a massive brush is moving over a field of plants.
Not everything is move, but just a width line bending the plants... looks epic :D
Have to find that example video. :)

edit2: another idea, just testing that.
Using the Xocean compound to create a wave abvove of the grass, using the distance between the wave and the grass to generate a weight map to control the strengh of the null/surface force... :)

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sant0s
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Re: Rotor Wind sim on geometry

Post by sant0s » 19 Jan 2018, 23:26

thats the goal, a massive grassfield (and than a helicopter or dragon pass by/hoovers above :D):


the result is still a bit blocky and the grass sometimes bends total what looks stupid.
But a beginning point and the tec works super fast, working on it. :)


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rray
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Re: Rotor Wind sim on geometry

Post by rray » 19 Jan 2018, 23:51

Maybe this could be done the low tech way with a turbulence field that controls a 2nd turbulence field that has a higher frequency (jitter for single grass strands). Maybe even a third on top for good measure.
No idea about controlled movement though atm except moving one field globally.
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

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sant0s
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Re: Rotor Wind sim on geometry

Post by sant0s » 22 Jan 2018, 13:41

Hey,
was playing with some Quixel Models/Textures, the grass model is form jesus fernandez.

The grass Animation looks crap, Dof and Lens Flare are just very quick comp, have to work on it - but rendered in more or less 45 sec per frame, only needed 64 samples max in HD without noise?! :D

It has that strong Dof, since its a close up of a bird later. :)


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sant0s
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Re: Rotor/Wind sim on instanced geometry

Post by sant0s » 26 Jan 2018, 21:23

Some more progress :)

Still lot of construction sites: integrate soil simulation, feathers, nice eyes, good comp, etc.



Having some problems, to get the feathers without jumping on the bird.
I guess, its becouse of the geometry changing sometimes.
I thought, I can solve that by adding more subs and smooth, than add the ICETree with the featers - but still flipping around.
Anybody had problems like that and solved it? Actually I think, I need something like the cage thing like in Pauls FUZZ, right?


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rray
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Re: Rotor/Wind sim on instanced geometry

Post by rray » 01 Feb 2018, 13:55

Looking good.

No idea about the weird feather flips. Point local reference frames should remain smooth even with a lot of animation. Unless the topology changes. Maybe there's some other coordinate systems mixed in that causes this.
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

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sant0s
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Re: Rotor/Wind sim on instanced geometry

Post by sant0s » 01 Feb 2018, 14:14

Hi rray :)

I guess, the problem is, that the topo is very low poly and so the feathers have problems on the edges, even when I subdivide the mesh.

Ill fix that, think its only some weights that are not good.