# Thick Smoke Dissipation **URL:** \ **Category:** Public\ **Created:** [March 1, 2012, 12:52pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559 "2012-03-01T12:52:30Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Paul\_Oblomov](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/paul_oblomov/32/41296_2.png) [@Paul\_Oblomov](https://forums.chaos.com/u/Paul_Oblomov)\ **Post date:** [July 23, 2012, 9:06pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/21 "2012-07-23T21:06:01Z")
Another option to get phx better, but it is not anyhow commented 😄 Love it 😄 ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [July 24, 2012, 5:03am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/22 "2012-07-24T05:03:33Z")
> [@Backwards compatability](https://forums.chaos.com/t/backwards-compatability/38890/6): > > here is the scene with the correction **Ivaylo.** That looks realy promising! Thank you very much! I´ll try to adapt this setup to my scene and I´ll let you know about the progress. And again I´m really pleased by the Chaos support. With no other software developer I have had this amazing experience. Kind regards. **Sascha** ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [July 24, 2012, 5:07am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/23 "2012-07-24T05:07:28Z")
> [@cojoo](#): > > Another option to get phx better, but it is not anyhow commented 😄 Love it 😄 **Hi Paul** 😉 Yeah, maybe this conservation method is worth a comeback - with detailed documentation and a good sample (the one Ivaylo provided yet is excellent) everybody should be aware of the dangers and the benefits… ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [July 24, 2012, 6:05am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/24 "2012-07-24T06:05:55Z")
here is the result of the last scene, 100 minutes for 500 frames simulation, and 2h rendering with vray. [![](https://europe1.discourse-cdn.com/chaosprd/original/3X/0/b/0b02cf726a2f8096ba454482e4f40b056b6812dd.jpeg "block") ](https://www.youtube.com/watch?v=wQWoFii97ZY) about the hidden conservation methods: actually this is not fully different method, it is just a modification of the smooth method. refltype=11 produces the same result as the usual smooth method in version 1.x of phoenix. this modification gives high convergence rate, i.e without it you can reach the result with quality set to very high value. however, this modification leads to some very annoying problems, and because of this it is hidden. but in some cases, it is very, very useful. ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [July 24, 2012, 6:28am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/25 "2012-07-24T06:28:16Z")
> [@No VrayMaps in Mat Editor after installing Advantage Pack 2012](https://forums.chaos.com/t/no-vraymaps-in-mat-editor-after-installing-advantage-pack-2012/38895/2): > > …but in some cases, it is very, very useful. Yes it is! Thanks again. ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 1, 2012, 8:02am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/26 "2012-08-01T08:02:26Z")
> [@No VrayMaps in Mat Editor after installing Advantage Pack 2012](https://forums.chaos.com/t/no-vraymaps-in-mat-editor-after-installing-advantage-pack-2012/38895/2): > > but in some cases, it is very, very useful. **Ivaylo** , hi, I have another question here:… In your samplefile I see, that you setup your geometry so that it definitely intersects at a certain amount. Is this important? Shall I avoid walls that touch each other with complanar faces? I always do pure and clean modeling with snapping, so my geometry does not intersect usually. Of course I do avoid **visible** complanar faces in terms of rendering due to AO and GI problems, but I always have **invisible / covered** complanar faces… Is this a problem? Do I have to modify the geometry for better simulation with PhoenixFD? Thank you and kind regards. **Sascha** ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [August 1, 2012, 10:01am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/27 "2012-08-01T10:01:05Z")
it is important only when inscribed geometry representation is selected, in this case the geometry should overlap a bit. ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 1, 2012, 10:05am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/28 "2012-08-01T10:05:25Z")
> [@How to get a UV map in the RE](https://forums.chaos.com/t/how-to-get-a-uv-map-in-the-re/38962/3): > > it is important only when inscribed geometry representation is selected, in this case the geometry should overlap a bit. Thank you, Ivaylo. ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 1, 2012, 1:50pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/29 "2012-08-01T13:50:15Z")
And again another question: When my smoke is travelling through the walls (geometry) - what do I wrong? Thanks again. **Sascha** ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [August 1, 2012, 2:09pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/30 "2012-08-01T14:09:50Z")
the most common reason is the use of inscribed geometry representation ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 1, 2012, 2:12pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/31 "2012-08-01T14:12:07Z")
> [@SreckoM](#): > > the most common reason is the use of inscribed geometry representation I use “center” - shall I better use “circumscribed”? Remind, I use the setup you provided in the “block.max”-sample. And you are fast! 😉 Thank you. **Sascha** ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [August 1, 2012, 2:31pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/32 "2012-08-01T14:31:22Z")
circumscribed is better, inscribed is used for liquids with thick walls ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 7, 2012, 11:29am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/33 "2012-08-07T11:29:51Z")
Work in progress **Ivaylo** https://www.youtube.com/embed/lY5cDaefC0Y?feature=oembed&wmode=opaque It starts working, but I have to crank up the discharge to 4000 - isn´t it a little like a jet engine? **Sascha** ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [August 7, 2012, 11:44am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/34 "2012-08-07T11:44:22Z")
the discharge is measured in scene units per second, for big scale scenes you need bigger discharge in order to achieve the same effect. ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 7, 2012, 12:05pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/35 "2012-08-07T12:05:57Z")
Discharge > [@Element AA problem](https://forums.chaos.com/t/element-aa-problem/38996/3): > > the discharge is measured in scene units per second, for big scale scenes you need bigger discharge in order to achieve the same effect. Can you please explain this more? The documentation says “The speed (not the quantity) of the discharged fluid. The quantity of the fluid will be equal to this parameter multiplied by the object’s surface.” So I have system unit scale 1 Unit = 0,1 inch - that means my object emits with 400 inches per second - but what means the surface multiplier? And isn´t 400 inches per second still very much? In a default scene (1 unit = 1 inch) a PHXSource starts with discharge 40. I have 100 times more if I calculate right… In my scene I do 2 diffenrent simulations: the biiig smoke simulator with discharge 4000 and a small hires simulator for the fire with discharge 400 (which fits the default of 40 with my scene units set to 1 unit = 0,1 inches). If I use a small discharge to get a nice fire I do not get enough smoke to fill the scene unless I crank up the smoke multiplier - which produces some weird dense smoke that is really hard to shade. So what would be the right way to achieve this: a nice small fire on the cooking place burning on and on producing THAT MUCH smoke that the whole building will be filled up? Do I have to crank up the discharge or better the smoke multiplier? Or do I have to try to achieve this with the transparency in the simple smoke? Or is it a mixture of all? Thank you again. **Sascha** btw.: What do you think about my smoke? ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [August 7, 2012, 12:47pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/36 "2012-08-07T12:47:00Z")
> that means my object emits with 400 inches per second - but what means the surface multiplier? > the surface multiplier means that your source produces 400\*S cubic inches per second, where S is the surface of the emitter. > And isn´t 400 inches per second still very much? yes, it sounds like a big value, but if your source has small surface (your case seems to be like this) the total volume of the produced smoke isn’t so big. > i think the best way to do this is to use smaller discharge and high smoke value of the source. to limit the density you can use curve based transparency (not simple smoke). ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 7, 2012, 1:04pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/37 "2012-08-07T13:04:18Z")
> [@Tupaia](#): > > to limit the density you can use curve based transparency (not simple smoke). Yeah, I tried that, but for me it´s hard to understand whats going on with the curve… For example: what would the curve look like to reproduce the simple smoke behavior? A straight line between lets say 0,0 / 0,0 and 1,0 / 0,1? What do x and y stand for? Is x the density value given by the simulation and y the transparency at a given density? I would like to understand what the curve exactly does and what will happen when I start to move the points around… Thaaaaankyouagain 😉 ---
**Author:** ![Ivaylo\_Katev](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/ivaylo_katev/32/3695_2.png) [@Ivaylo\_Katev](https://forums.chaos.com/u/Ivaylo_Katev)\ **Post date:** [August 7, 2012, 3:27pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/38 "2012-08-07T15:27:15Z")
> For example: what would the curve look like to reproduce the simple smoke behavior? A straight line between lets say 0,0 / 0,0 and 1,0 / 0,1? > not exactly, but it’s near, it should be curved in negative direction. > Is x the density value given by the simulation and y the transparency at a given density? > yes, it is. with the additional note that y meaning can be switched between transparency/opacity. the “density value” is actually one of the channels exported by the simulator, it can be temperature, smoke, even velocity. i.e. you can make the faster parts of you simulation to look dense 🙂 > i would recommend you to use the curve of the scene “nuke.max”. you can do this exporting/importing it with the right button ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 7, 2012, 3:41pm UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/39 "2012-08-07T15:41:51Z")
I´ll check this tomorrow… 🙂 EDIT: Learning A LOT about Phoenix! Thank you Ivaylo. ---
**Author:** ![Sascha\_Selent](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/sascha_selent/32/4796_2.png) [@Sascha\_Selent](https://forums.chaos.com/u/Sascha_Selent)\ **Post date:** [August 9, 2012, 6:29am UTC](https://forums.chaos.com/t/thick-smoke-dissipation/40559/40 "2012-08-09T06:29:21Z")
Work in progress **Ivaylo** Take a look 😉 https://www.youtube.com/embed/ql-WTxlJvJw?feature=oembed&wmode=opaque The smoke with a lowResGrid (16mio) - sim time is too long, I´ll further reduce the resolution and bring up the vorticity and the random amount a bit. [Previous page](https://forums.chaos.com/t/thick-smoke-dissipation/40559.md?page=1) [Next page](https://forums.chaos.com/t/thick-smoke-dissipation/40559.md?page=3)