Temperature question

[superrune]

Hi,

I am doing a simulation with just smoke, trying to do something that looks like dry ice.

The manual states that you can "Select the Simulate Temperature checkbox to include it in the simulation", but I can't seem to find that check box in the UI. Since I cannot turn off the temperature, can I simply ignore it? Or is temperature also used when simulation smoke without any fuel (or fire)?

Thanks,
Rune

[Solitude]

Temperature can be emitted without fuel... and so it can affect smoke. Check out the members area off the main page. In the examples section you can download the file from the gallery image of the dry ice style smoke.

[superrune]

The vapor example is beautiful, really great as a reference! Thanks for pointing me to it.

One thing I found lacking in your tutorials are some explanations on why this and that value is chosen. The tutorials just run through a scene saying "this is set to this, that is set to that", with absolutely zero explanation. I would really like a tutorial that explains why the values are as they are, otherwise it just feels like random tweaking.

For this project I am doing, I need to make some dry ice that dissipates rather quickly. Let's say I took this cold vapor sample file, and I wanted to dissipate the vapor just as it reaches the logo - what settings would I need to change and why?

Thanks,
Rune

[Rif]

Hey Rune ,

I couldnt Agree more with you about the Tutorials.. Unfortunatly i think turbosquid was simply reading tutorials and doing them that Roman and ari wrote for them or so and running out of time toward the end of ffx release..

For dissipation , its quite simple : In the Simulation Tab , you have Both Smoke Dissipation and Temperature dissipation .. In your case , what you want to achieve seems to be that the vapor dissipate .. Simply understand few things about theese dissipation parameters :

1- Dissipation Min.Density is the Treshold at witch Each Voxel Density Will start to be affected by your Dissipation Strengh..
2- Dissipation Strenght is the Amount of Strenght that the Dissipation will be aplied ON treshold reached ..
3- Diffusion is some kind of a Blur that will be aplied on the Smoke Densitys to Difuse them in the Air and in the rest of the grid.. this option can get costy so i would suggest to keep it at 0 as you dont need it to achieve your specific task..

In other word , Say you have a Source Density from an Object Source set at 10 ..Fume Will dissipate Naturally no matter what.. In your Case it seems thats its NOt enough so Examine based on a VIsual Ratio ( in your Preview Window Perhaps) the Amount of Natural Loss that you want your Smoke To be Starting to Dissipate from .. This will be Your Treshold of Min.Density for Strengh affectation.. Then All you need to do is put that number ( example 5.0) in your Smoke Dissipation min.Dens and start cranking up your Dissipation Strenght ( example: 5.0 ) .. This Should clearly show you on your next sim where you where near with your treshold or whether your strenght is not enough or too much.. you then can tweek adequatly..

Same Process can be aplied for the temperature if needed.. all though for your task i would think it would mess up your whole timing\speed as temperature is exponential to the BOyency and timescale etc.. .

Hope that helps out ..

[superrune]

Cool, I will see if I can get my head around this....

So if I understand correctly, there's a connection between the "Dissipation Minimum Density" and the Viewport treshold values, meaning I can use the display values to find out at what density I want the Dissipation to occur? Is that right?

Rune

[Rif]

I never did that this way , but You can Probably do that .. I alway did the source\simulation connection way brute force tweek: Density from the source , lower dissipation , render tweek at low rez grid Or look at the preview Window as i said ( witch is pretty fast) and then when it dissipate from where i want 2 then big sim and let it cook..

But , theoricly your understanding is right , so it would be interesting to see if you can reach your result of dissipation tweek using the viewport dots notification (.. I just dont try those cause of old bugs that staid in my head but that are not in the software anymore . heh.. Let us know how that goes !

hope that help !