Need help on Tornado simulation

[Blacko0ps]

Hi Guys,

I just started learning about smoke simulation. I am trying to create a tornado simulation using smoke solver instead of Pyro. I followed the custom force tutorial from Ben Watts. The problem that I am facing is that when I start my simulation, after a while the smoke spread out and remains floating and it doesn't follow my velocity field.  How can I get it to follow my velocity all the time, or is there anyway to kill the smoke based on their age?

I have attached a quick preview and my hip file. 

Thanks, 

Preview.mp4

Tornado_test7.hiplc

Edited November 12, 2016 by Blacko0ps

[dimovfx]

You can try to add small inward velocity. Or adding dissipation based on velocity. Also maybe you can try "gas curve force".

[marles]

Hi, Or maybe you can use a vortex force in DOP to keep your smoke turn around your main axis. To do that, you need to create the orbit's attribute from your deformed line (create a vortexforce atrribute next to the line) and then use them to drive the vortex force in your DOP. You can control the vortex in 2 node: in the vortex force DOP and in the VortexforceAttribute in SOP.

See the hip below, the red node are the news.

ps: i'm not sure if it works, because i didn't have the time to run the sim totally. Let us know.

Tornado_test7.hiplc.hipnc

[rtep]

Here's a slightly different set up that I found worked well to keep the smoke moving.  I modified your set up, it's not perfect but it will show the workflow.  You scatter points in the bounds of the tornado, transfer your rotation vel to the points and bring them into the dop as a gasparticlefield. 

 

Tornado_test7_rtep.hiplc

[Blacko0ps]

Thank so much guys for your help on this one. I end up controlling the smoke with Gas Dissipate, Gas Combustion, and Gas Disturbance nodes. It worked pretty good.

Here is the result. Although, I am still not really happy with detail level of my smoke. Also, I am gonna work on the house destruction effect. Looking forward to hear your suggestions and feedback.

 

 

 

 

[anto187]

cool bro, you can enhance the detail using arnold i think, displace the shader using noise. hope it help.

[StepbyStepVFX]

For a good tornado setup, I encourage you to look at those FXPHD tuts, where they start with particles and sample them to create velocity field. Very interesting and lots of control over the look you want achieve :

https://www.fxphd.com/details/491/

https://www.fxphd.com/details/502/

[Midasssilver]

Nice tornado! My main note would be, tornadoes usually have a velocity that travels upwards, as opposed to downwards, like in your sim.  Might want to research this a bit more and possibly reverse that direction.  Also, adding a little twist to the top clouds would probably help as well. Cheers

[duongduy92]

Hi guys, 

I'm also working on the tornado simulation. I'll share with you my setup below. I have one question too. I would like to achieve an explosion effects like the twister in the movie Into the wood. I'm stucking on this one for awhile. Could somebody jump in and shed me some light? Thank you very much. 

intoTheWoodTwister.mov

Tornado_v2_3_discord.hip

xoay.obj

[Blacko0ps]

I got a chance to improve the tornado project a few months ago and here is the result, although it's a fire whirl now :