How to separate fields from same sim? Dopimportfields mixes floats & vectors leading to ridiculous storage cost and longer geo save time

[Coz_y_not]

I have a smoke sim in a DOPNET and a Dopimportfields initialised for smoke showing density, vel, temperature.

is there a way to run the simulation only once and save separately the density, vel and temperature, each in a separate file cache?

is it possible to do it with several dop import fields nodes? or somehow have as many outputs to the dopimportfields node as the number of fields, e.g. Density has its own output density, and the same for the others each with its own output? and then a file cache with 3 inputs each saving separately one of the fields

 

Edited 13 hours ago by Coz_y_not

[tamagochy]

This is not good way because in this case you will have 3 simulations. You can cache all together and than take field you need and work with it. If you still need separate files(I dont know what a spesial case you have) you can save it from cached VDB to save a lot of time.

[Coz_y_not]

Here is why: These are a few tests for a tiny sim (DTV: Density and Temperature and Velocity).

For the same simulation, same frame, if you save:

• Density alone -> 55mb
• Temperature alone -> 55mb
• Velocity alone -> 55mb

Theoretically I should be able to get away with 165mb total storage

if you mix floats you're still good: density and Temperature: 55mb + 55mb = 110mb (exactly as simulated and saved, exact sum)

Up till now, I should be able to use only 110mb (density & temperature together) + 55mb (separate velocity) = 165mb total storage

Once you feel like mixing apples and oranges, funny things start happening:

Density (float) + Temperature (float) + velocity (vector) = 425mb total storage (I repeated the test 3 times because I couldn't believe my eyes)

can you explain the difference between 165mb and 425mb? (425/165=2.5)?

Try repeating the test and see for yourself.

Can you explain to me why I should buy 2,5 times the storage instead of 1 just because floats and vectors are being mixed in one output?

In case of a large simulation, instead of paying for only 1 drive, you need to pay for 2.5 drives. Scale that cost up for more servers / farm, and your numbers start having a louder voice. Instead of 20 drives you need 50 drives, for the same bloody sim, it gets funny real quick.

No one paid attention so far (I wonder why) to the fact that the dopimportfiels is mixing apples and oranges at a very high dollar cost for no reason + ridiculously 3x longer geo saving time, 

It needs to be fixed by having 1 simulation but the dopimportfields offers 2 outputs, one for floats and one for vectors, from the very same simulation (no re-sim):

1. floats separate (all of them): Density, Temperature .... 
2. vectors separate (all of them): velocity ...

and just for arguments sake, I did resim, and it was way faster to resim twice (float separated from vectors) than to sim once (mixing apples and oranges) because saving geometry takes forever when you mix apples and oranges. But this is not what I want, re-simming is not the way to go, I need saving separate floats and vectors from the same simulation.

Is it possible to do it with PDG (2 simultanuous dopimportfields for the same frame from the same sim)? or to change the dopimportfields node?

Edited 13 hours ago by Coz_y_not