[novice] Using slice tool to speed up FLIP simulation preview on single machine

[art3mis]

Hi

Normally the Slice

https://www.sidefx.com/docs/houdini10.0/shelf/slice

or Slice along Line

http://www.sidefx.com/docs/houdini10.0/shelf/slicealongline

tools are used to slice a FLIP fluid for distribution among several machines.

However, I would like to use it so that I can simulate just a single slice on 1 machine, in effect giving me a very fast preview.
Can any FLIP experts tell me how this might be achieved?

[art3mis]

Ok the following is supposed to work but...I have no luck. For one thing, where in the world is the 'Gas Net Slice Exchange node'? I searched in my Tree View but see nothing resembling that name.

From

https://www.sidefx.com/docs/houdini/fluid/tips

 

• To make a high-resolution particle fluid system run faster for prototyping or visualization, you can simulate just a slice of the system using the tools normally used for distributing to a simulation farm.

  Use the Slice and Slice Along Line tools on the Particle Fluids shelf tab to slice the system into regions. Then click the Distribute to set up the distribution nodes.

  Finally, you can select the "control" node created by the distribution tool and set the Slice parameter to the slice number you want to view. (You can turn the distribution system off by bypassing the Gas Net Slice Exchange node).

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Edited October 31, 2016 by eco_bach

[galagast]

 I haven't fully tested distributed sims yet.. But the "Gas Net Slice Exchange DOP" is a node that is created by using the Distribute Particle Fluid shelf tool.

Here's a quick 5-step run through of what I did (as I had time to spare ).

1. Create a long box.
   
    
2. Create a FLIP from it using the Shelf. (select the box)
   
   
   
   Current DOP network:
   
    
3. Click "Slice Along Line" Shelf tool. (select the flip solver)
   
   
   
   Your DOP network should now look like this:
   
   
   I optionally adjusted the slicealongline1 parameters to this:
   
    
4. Click on the Distribute Particle Fluid Shelf tool. (select the Flip Object)
   
   
   A pop-up would appear (select any for now --- I chose Slicing)
   
   
   The Updated DOP network for distribution should now look like this:
   
   * Encircled in green should be the Gas Net Slice Exchange DOP you are looking for.
    
5. To test and simulate just a portion/slice of the sim, simply replace the value of the Slice parameter on the DISTRIBUTE_flipfluidobject1_CONTROLS node to your desired slice number.
   
   * You will need to RMB->Delete Channels the parameter first. But return it back to $SLICE prior to doing the final distributed sim.

I hope this helps!

Cheers!
Jeff Lim

 

Edited November 1, 2016 by galagast

[art3mis]

Thanks Jeff! I more or less had already followed your steps but was looking for a node named literally "Gas Net Slice Exchange "

Sometimes I think the documentation assumes everyone already has 10 years experience with Houdini:)

Edited November 1, 2016 by eco_bach

[Atom]

Jeff,

I tried your steps and it does not seem to work. I tried it both with a fluid object, as you describe, and also with a FLIP tank.  The steps are explained well, so thanks for that but when I try to sim just slice #3 the fluid sim explodes and does not work.

I expected just the center portion of my FLIP tank to simulate and all other slices to remain static. Is that the way this tool works? This is a new feature to me.

ap_slice_render_flip_tank.hipnc

Edited November 1, 2016 by Atom

[art3mis]

I seem to recall experiencing something similar. ie the particles just flying off everywhere after I slice the tank:(

Perhaps because I hadn't bypassed-disabled 'Gas Net Slice Exchange DOP'?

Dunno, will give it another try

Edited November 1, 2016 by eco_bach

[galagast]

Indeed, on my test scene above, the particles just falls down.
So I tried fitting and closing the boundaries, now it's also bursting.

After further testing, it seems that the "Distributed Pressure Solve" is causing the burst.

Distributed Pressure Solve OFF

And watching the Pressure Visualization, there are frames that the pressure seems to zero out.. which could be causing the burst (?). The pressure solve might be needed for the final sim.

I also recall that after sending the distributed sims to the farm, each slice would always start with the full particle count, I can't quite recall how to properly deal with that after the sims. The solution might be somewhere on the masterclass video.

 

Edited November 1, 2016 by galagast

[tamagochy]

You cant sim only one slice bacause it depend from neared. It takes fields from border to initials values.

But i have another problem. If i made simulation not from shelf tool i cant make distribution. It gives me error "object haven't name attribute. And i don't understand what its mean. What name attribute its looking?

[art3mis]

tamagochy

Please see my 2nd post

From

https://www.sidefx.com/docs/houdini/fluid/tips

 

• To make a high-resolution particle fluid system run faster for prototyping or visualization, you can simulate just a slice of the system using the tools normally used for distributing to a simulation farm.

  Use the Slice and Slice Along Line tools on the Particle Fluids shelf tab to slice the system into regions. Then click the Distribute to set up the distribution nodes.

  Finally, you can select the "control" node created by the distribution tool and set the Slice parameter to the slice number you want to view. (You can turn the distribution system off by bypassing the Gas Net Slice Exchange node).

•