fluids, velocity (static) why?

#1

hi

fluidShape in maya has tons of adjustments… and of course I’v used and read about them…

but I have a question that couldn’t understand … please clear this to me!

we have options to set the density/velocity/… to Off/static/dynamic/gradient right?

but consider that we a velocity set to static!!!

how is it possible velocity to exist in a voxel but in static mode and never used in dynamic simulations( which in my opinion impossible and unnatural) ?
on the other hand how is it useful to have such information …???

considering this is possible to have static velocity which doesn’t push the existing density to other adjacent voxels … so what does diffusion do ???
I mean, is it possible to imagine a moving density (due to diffusion factor), without any velocity??

totally I mean if there is diffusion, there is velocity, no matter the velocity is set to off/dynamic … etc.

and … velocity could have Off/dynamic/constant(maybe) , not static option!

hope I can clear it out what I’m asking…

thankx

#2

The value in the velocity grid changes from frame to frame when it is dynamically solved. In the normal simulation the velocity pushes its self. When it is static it is simply whatever the initial state velocity is for the full simulation. One could for example paint a fixed flow path into a fluid then use that as a static velocity to push density or, if the fluid is used a field, particles.

#3

yes, now I get it sir!

thank you :slight_smile:

#4

another very important question for me… that took me so long to understand…

in the document we have:

Replace moves contents through the container towards a specified amount. This amount is set by contents/Voxel/Sec attribute and the rate at which this fixed amount is achieved is set by the Rate (Percent) attribute. If the contents/Voxel/Rate for a property, such as Density, is set to 0, then contents are removed from the container.

I don’t know the equation is behind density/voxel/Sec …

I mean I have …

Rate ( percent) = 100
density/voxel/Sec =10
density scale = 1

density/voxel/Sec tells me that a voxel will be filled 10 ( of what??) per second… ( sorry very confused about this :sad: )
so the replace method wants the Density to reach to what amount of density per voxel according to these setting??

in another word when a voxel knows that is filled by Specific amount of Density and now density should fill the adjacent voxel?

this is a very confusing problem for me… pleassse clear this to me!
thank you in advance

#5

this is the same question …

for example Heat/voxel/sec … set to Replace right?

what is the specific heat number ( degree,Fahrenheit, … whatever!) the fluid emitter is trying to reach to?
1, 200,2.5 … full voxel, half the voxel, any way but what is the Unit used for temperature ?

please help … I really need to figure this out!

#6

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