Waasha Posted June 22, 2013 Share Posted June 22, 2013 Hi, I'm doing a tornado project with custom velocity field made from POP NET, but I have a problem with the centrifugal force - the smoke is leaving the area where the particles are turning because of the centrifugal force.. I tried adding the centripetal force to the particles outside the main tube (I'm not doing a classical tornado shape - widening to the top, but just a simple straight-tube-shaped tornado ), but that didn't help - the swirling speed is too strong, so some fluid always escapes my main tube and there it stops. I tried adding a collider outside the main tube, but that doesnt work well and it's adding very much to the sim time... Is there a way I can map dissipation to the velocity? So that when the fluid is stopping, it will disappear? I need the the time dissipation quite low, so that the fluid has enough time to go from ground, where I source it to the few meters height.. But if i could somehow have something like the time dissipation = low and the velocity dissipation = high (when velocity is low, the gass will quickly dissipate), it would fix my problem with fluid leaving my main velocity area... hope it makes sense... Any advice GREATLY apretiated.. p.s.: sorry for any mistakes, english isn't my natural language.. Quote Link to comment Share on other sites More sharing options...
bunker Posted June 22, 2013 Share Posted June 22, 2013 you can use a gasfield VOP here is pseudo-code (nodes), where "dissipation" is a parameter vel > length > fit_range > ramp > a density * (1-dissipation*a) > density 2 Quote Link to comment Share on other sites More sharing options...
Waasha Posted June 24, 2013 Author Share Posted June 24, 2013 Thank you VERY much for your advice, bunker! I have few questions, if I may: 1) where do I plug this gasfield VOP? I guess to the last input of the pyrosolver? But I'm not sure.. 2) that "a" is some parameter, which I get from the ramp, or....? 3) dissipation is DIRECTLY a parameter of the field VOP, that I can use? I am a little unsure, because for example velocity is stored in the field "vel", so.... And one last question - Maybe I could solve this whole problem by somehow make the fluid without the centrifugal force, so that it doesn't escape my circular velocity field, but I hon't know how.. I tried the drag force (with high torque value) after the pyro solver, but that didn't help.. On the little scheme is the top view of the problem I'm trying to solve.. Just to explain: I need to source the density from the ground, so I need the dissipation to be relatively low, so that the smoke has enough time to get up to the 6m height.. But with this low dissipation the smoke that escapes my velocity field is just sitting outside and inside the tube, waiting to dissapear... I think the "torque way" is the way for me, but I don't know how to do it.. the drag force torque didn't have almost any effect... Thanx for any help! Quote Link to comment Share on other sites More sharing options...
Waasha Posted June 24, 2013 Author Share Posted June 24, 2013 Here are some of my many test scenes, each driven a little diferently... Hope it clarifies what I'm trying to achieve.. I'm using volume settings I found in the examlpe here (I think it was yours, bonker, but am not sure - thanks a lot! ).. So all i need is the volume to hold in the main velocity area and don't escape out or in... If anyone has some idea, i would be VERY gratefull... Thanks! example_driven_by_particles_1.hip example_driven_by_particles_2.hip example_driven_by_field.hip Quote Link to comment Share on other sites More sharing options...
dobin Posted June 24, 2013 Share Posted June 24, 2013 here is the bunker's advice in action: example_driven_by_particles_dissipate_1.hip D. 1 Quote Link to comment Share on other sites More sharing options...
Waasha Posted June 24, 2013 Author Share Posted June 24, 2013 dobin, thank you VERY much, this is perfect! You are my savior Bye! Quote Link to comment Share on other sites More sharing options...
Vivoco88 Posted September 10, 2013 Share Posted September 10, 2013 (edited) hi =D, I have been trying to make my tornado with mr bunker's method, but it doesnt work at all with my file =(,it's just the tornado keeps generating smoke that doesnt follow the velocity or it will just dissipate leaving my tornado with no detail at all. Please kindly help me =D Thank youu =D Edited September 12, 2013 by Vivoco88 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.