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daehuck

Rotor wash dust question!!

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Hi all,

I'm doing helicopter's rotor wash dust and have a issue.

added mov and hipfile is my rotor wash

I used circle so I can emit smoke like a ring-shape

but circle has a hole in the center.

I want to fill the hole but have no idea

I'm doing with particles but it doesn't work well

When I downsizing the circle, volume became too small and hard to see...

How can I approach to the solution?

Any comment is good for me. :)

20131111_rotor_wash_flip2.mov

20131111_rotor_wash.hip

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Have you tried scattering points across the circle and switching the fluid source method to 'stamp points'?

It can be a very good and simple solution. Thanks woodenduck!

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hmm... scattering is a well solution, is there anyways to get rid of emitters? whatever I made(fluid source volume or particles) emitters are bordering me. They stood in the center and it looks very bad. I want invisible emitter... Any thanks for your kind reply.

Edited by daehuck

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Don't know how to make smoke emit from nothing. There might be some density/life trickery you could do, but I don't know off the top of my head.

I just tried adding some animated noise in to the volume source and I think it is an improvement, though perhaps not entirely what you looking for.

See attached.

Good luck!

WD

rotor_wash_WD_02.hip

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oh, thanks for kind reply again :)

yeah...it is hard to emit smoke from nothing. I think there may be exist some trick...

I think using particle advect is the best way...

But I don't know how to make a nice smoke from advected particle motion

use them as a emitter again? I don't know...But have to try it

I'll check your file early in the next morning,,,cause im in home now and have no houdin...

Anyway Thanks again WD!!!!!

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Don't know how to make smoke emit from nothing. There might be some density/life trickery you could do, but I don't know off the top of my head.

I just tried adding some animated noise in to the volume source and I think it is an improvement, though perhaps not entirely what you looking for.

See attached.

Good luck!

WD

I checked this file and looks fine. I've tried this method before but I don't know how to modify the speed of noise, So I used vopsop and add a noise based scattering~ but it looks not fine. Now I find pulse duration adjusts speed of noise. Thanks!! Edited by daehuck

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well to get a emission from nothing, you have to create a emitter:)

just don't render it and use a density ramp together with age to let the smoke density fade in, that way it looks like the smoke comes from nothing.

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well to get a emission from nothing, you have to create a emitter:)

just don't render it and use a density ramp together with age to let the smoke density fade in, that way it looks like the smoke comes from nothing.

What a nice solution! Thanks very much :)

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well,,, have a one more question...

according to the JuriBryan's advice, I checked the <smokeobject1 - multi - density ramp > but it is already increasing(fade in). And it is related with overall density not separately generated smoke(I think)

and I have no idea about 'age' attribute,,, cause it is not a particle...

So I use a gasfieldvop and make a ramp from 'time' and multiply it with density. But it looks different from what I want.

Q = How can I get a 'age' attribute?

Q2 = It has to be done in gasfieldvop? or shader or anywhere else?

Edited by daehuck

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Guys I tested it in the other way...

with popadvect

which way looks more realistic??

any comments will be appreciated!! :)

and if use it as a emitter again then additional smokes will appear. Finally it doesn't match with pop's movement. Is there any suggestions??

20131114_popadvect2.mov

Edited by daehuck

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hey,

you are right, sorry about that. I did not find a way to create a age volume as well... maybe a real houdini master like Bunker knows how to generate one.

But seeing that you will have a circulare emission you can cheat it...

I had no chance to test it in renders, since my license is rendering at the moment, but seeing that you can scale the density to what ever you want you should be able to get the look you want with the ramps in the pyro shader.

In my test file you will find a VolumeVop, that uses a point cloud look up to get a spherical distance to the density... meaning you can control from what point onwards there should be density.

Just adjust the radius to the max scale of your emitter and you wont see it anymore.

Then inside the vop play with the max volume of the fit node to control how much density should be shown inside of the look up radius.

This is a very very crude method... and I would love to hear from some real houdlni masters how this should be done.

Cheers,

Juri

rotorWash_v01.hipnc

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it is created in H13... works fine on my machine, but its really far from the best way of doing it anyway:)

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