Tips and Tricks: A typical Hybrido scene

Hi all,

keep in mind this steps when you create a Hybrido scene:

1- Put a GridFluidDomain (in surface tab put the Calculate surface to Always and the Source to “From field”)

2- Once the GFD is simulated, put the Calculate Surface to cache and the GFD to cache too.

3- Put the splash, wet or waterline emitters ( you can use “splash_and_foam”, and “wet_and_foam emitters” too). Connect them to the GFD and any daemon you want.

4- If you put a splash or wet emitter emitter put it to cache. Put a foam emitter (keep in mind that the foam can’t be affected by any daemon force or other emitters so you can’t link it to anything, except the GridFluidDomain or Kvolume). Connect it to the GridFluidDomain.

5- Put the foam in cache and put the gridmesh.

6- Put the Calculate Surface in the GFD to Always and change the Source to “From particles”.

7- Modify the auto radius, smooth and auto cell size to calculate the mesh.

8- Click on the Build grid Butoon in the surface tab to check how the mesh will be working.

luisM.


		

27 comments

  1. thanks.It is intelligible.
    You should add this to page 1 of RF manual.
    by the way,
    I want use From Particles in step 6.
    Should I set source option = From Particles in “step1”?
    or From Field?

    1. Hey,

      I forgot a step for the 9 step. I’m going to put a post to explain that, but basically, when you want to calculate the particles, the “Source to” should be “From Field”. Why, because once the GFD is simulated from field, a new file will be created which will be used when calculating splashes or foam and the simulation for this splashes will be faster than using “from particles”. On the other hand, you should to put “from particles” when you are calculating the mesh because of the GridMesh will be more approximated to the GFD particles.

      I hope it helps.

      luisM.

  2. thanks for the tips, but i was wondering if it can be possible to calculate splash and wet from particles generated using a common circle or square emitter
    i’m asking this because i’ve a scene created that way, and i’d like to improve it with splashes, but can’t find a way to do it, were hoping a GFD could take precalculated particles using common emitters, but it seems there’s no way to do that
    thanks in advance for your time

    1. Hi Mario😉

      Yes, you can use any sph emitter converting it to splash emitter. You have two options to do that. First, you can use the scripting to send the particles you want to a splash emitter. Another possibility and easier is by using the daemons “Move_to_GD_splash” but it needs to be downloaded from http://resources.realflow.com/news_scripts.php?t=2#page=1&mode=0&id=146. With scripting you have more control over the particles, but with the daemon is very easy.

      luisM.

  3. Hello Luis.

    Where is this Surface tab you are talking about? It´s in the GFD Parameters?

    Thanks

    Reinaldo

  4. if I put calculate surface to always, my simulation goes crazy, like water calculates slowly, won’t hit grid walls, instead will disappear, and eventually will explode. if I change back to “on request” it simulates as it should… any clues?

    1. Hi Rafael,

      It is a weird thing. It is true that the simulation will be a bit slower but it shouldn’t be too slow. Are you talking about calculating the Grid Fluid Domain or splashes?. If you are talking about GridFluidDomain it should be ok if the surface parameters are “always”. If you are simulating splashes, one the gridfluid has been simulated you should put the surface parameters “On cache” and the GFD to cache as well.

      luisM.

  5. cmiVFX Hybrido in Action is so great which help me so much in daily work, but I meet some problem while I was making the scene followed you tutorial:
    1.Grid_Fluid_Foam & WaterLine:I change the resolution and resimulate my scene, the amount of generated particles are as more as before, nothing changed, and change emission rate of WaterLine alos do not change anything about particles number. But in your video I found you change resolution for Foam and it works well.
    2.Grid_Mesh : After I changed cell size and radius in GFD, rebuild the Grid_Mesh, the amount of meshes do not change, no matter what value I typed in Cell Size and Radius, the amount of meshes do not change a little.
    3.Grid_Mesh : The optimize settings in Grid_Mesh @Quatity factor @Reduce Percentage do not work, I changed both of them to a very low value, rebuild, nothing happened, the meshed are as more as before.

    1. Hi miedie!,

      About your questions

      1. Keep in mind that when a splash particles is colliding against the GFD surface, the particle will die and a new foam particle will be born. So, the number of foam particles will depends on the number of splash particles as well. The waterline has several parameters to control the amount of particles. The first parameter is the “Emission rate”. If you put a low value here, it means you’ll have more particles in less time. By default is 30 so it is generating particles each 30 frames. Then, the min and max % particles will change the amount of particles when they appear.

      2. Make sure you don’t have the “Calculate surface…” parameters to “Use cache” or “On request”. It should be in “Always” when calculating the GridMesh.

      3. Check the point 2.

      luisM.😉

      1. Thank you very much helped me so much, you really enthusiastic, later there are many questions to ask you, first thank you!

      2. Sorry for trouble again, I have a question about Only Simulate Foam Map, I have a scene with splash already been calculated, now I want to calculate foam, I do not want to simulate foam particles, I only need foam texture, so I turn calculate partitles in foam panel off, turn on calculate texture, then I press simulate button, the foam gray images are exported correctly in my foam folder, but along with frame incease, my computer memory is occupied more an more! Never get down untill my OS is die! My idea is that the next frame data only need 1 previous frame data, so the more previously frame data should be cleaned up from memory? But why? Please teach me, thank you very much ^_^

      3. Hi miedie,

        There is a trick to simulate the foam faster. Simply put the substeps min and max to 1. It is due to the foam is calculated over the GFD surface movement, when a splash particle is colliding against it. So, if you have the substeps to 1 for and 333 for max, the memory will be increasing depending on the amount of splash particles you have in the scene. In addition, make sure you don’t have the splash and the foam linked between them. It is not good😉

        luisM.

  6. This is a good checklist, but what are the steps when you also want to export a displacement texture, in order to get the foam and splash offset to interact with the displaced surface?

    1. There is a trick I use to export the displacement maps. Problem whit the displacement is it will take long time to simulate even if the GFD is cached. Why?. Because RealFlow will need to read the GFD before creating the displacement and if the gdc files are huge, it takes long take to read them. So, the workaround is, in a new scene in realflow, you must create a new Domain. The size can be as you want. Now, copy the displacement parameters from your original scene to the new one. Next, put a very low resolution. Particles are not important here so the resolution can be 1000 or 10000, or 10 if you want. Once the displacement maps have been created, copy them to the displacement folder for your original scene.

      I advice you when meshing that you simulate a couple of frames, including the displacement maps. Next, calculate the grid mesh and meshing the simulated frames. Once you have meshed the frames, and with the mesh displaying in the viewport, set the displacement shader for the mesh and now you can change the parameters for the displacement watching the changes in the viewport and setting them as you want before simulate all sequence.

      I hope it helps.

      luisM.😉

  7. Is it your opinion not necessary to connect the splash to the objects that are causing the splash?

    I thougth maybe the splash would go through instead, but maybe it’s not visible. It’s very much slower for me to calculate when I link the splash emitters to the object that’s causing the splash.

    1. Hi David,

      In my opinion it is not necessary due to, as you say, the simulation will take long time to simulate. I advice you to put a K collision so the splash particles colliding with the geometry will be removed doing the simulation faster and more natural.

      luisM.😉

      1. Ok, yes that’s a good way to go I guess.
        To detect collisions with the geometry it still needs to be connected right, but you I guess what you’re saying is this will be significantly faster anyway?

  8. I am using realflow with grid fluids, long story short i am simulating a simple but potentially quite large sim of rushing water down a stream (classic). My sim looks good but after a few hundred frames it wont hold any more particles, the stream continues but the particles don’t continue down the stream. Almost like there is a clipping border but its not a sharp edge.

    My domain is the right size but it’s almost like the grid can’t hold any more particles (only currently at like 350000), and i can’t find a max particle setting in the grid domain anywhere nor on google.

    Please help.

    1. Hello,

      Usually there is not a limit to emit particles if you have an emitter in stream mode. Do you have a kvolume or any daemon to kill the particles? Do you have an initial state for the hybrido domain before simulating?

      luisM.

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