Splash Tank sim cache

[Fostertron]

Hi Guys, another stupid question. 

 

Every time I create a splashtank sim, I'll stick it at frame 150 for example. Once the calculation is complete, I can view those frames of the sim. Now, I'll save that .hip and then close the file for example. When I go back to the file, it seems that I need to re-calc the 150 frames again which can takes hours if the tank is large and the particle separation is low etc. 

 

What am I missing? Do I need to render out each frame as .geo under wavetankfuid? Then they're always ready to import without re-calcing ect?

 

I can't find a tutorial to explain this so I'm sure I'm missing something obvious. Here's my progress so far but I need to keep the file open or I'll loose the sim....

 

 

Thanks again for any help!

[cwalrus]

Yep - with any sim you'll have you'll have to recaclulate it each time you change anything. While you're working with it, it has cached it to ram, which will be indicated by blue on your timeline. 

To cache out to disk on a splash tank - it looks like you want to choose the fileCache node in your splash sim, pick a place for the .bgeo file sequence, and then choose "Write" under the File Mode. Then click render - after it has finished, change "Write" to "Read" and that should work.

[Fostertron]

Thanks very much Cameron, 

 

I'm trying that now. I had tried it before but to someone who's new to this, there are so many options and seemingly so many ways to do things.  

 

I'm getting this file format in my geo folder:

 

.surface_cache.1.bgeo.sc

 

Does that look right?

 

Also, is this file just for the main splash fluid and not the spray/foam/bubble? Do I need to do the same process for these too?

 

Where do people learn these things other than on courses or the forums? The documentation seems to describe everything in detail but doesn't seem to explain workflow. The tutorials explain a vast amount which is great but there are still gaps regarding workflow etc. 

 

I'm probably just not paying enough attention!

 

Thanks again,

 

Kyle

[Atom]

I learned a lot about the FLIP system workflow by watching the VFXPipe line tutorial on the flooded hallway. Caching and Whitewater are also covered.

Once you realize that Houdini is really about preparation and display the whole simulation/cache system starts to make more sense. In the end all you need is a file node and material for a complex scene.

Edited October 19, 2015 by Atom

[Fostertron]

Thanks again Atom, 

 

Those videos are great and they're also short and concise compared to a lot of others. Easier to take in imo.

 

I'll make my way through those videos but ever since Camerons reply, I've been thinking of something else. My first question on this forum was whether it's possible to comp a splash/wave layer tank over an ocean wave surface. 

 

After matching the oceanspectrum settings for each, I just can't understand how to make the look/colour/attenuation of the tankfluid look like the oceanwave. 

 

I've been trying to decipher the purpose of the wave layer tank compared to the splash tank:

 

This tool creates a FLIP tank simulation of a thin layer of water on top of an ocean surface. The particles are initialized with ocean velocities, and the ocean surface at a specified depth acts as a collision layer underneath the particles, allowing the particles to roughly match the ocean waves.

 

I'm wondering if my understanding of these tools is all wrong. I thought that I needed to comp the entire tank rendering over the ocean wave surface. Do I actually just need to extract the foam/spray/bubbles from the sim and comp those of the ocean? And the tankfluid is simply there to allow interaction of the foam?

 

Sorry again for all the questions but thanks for all the help. 

 

Kyle

[cwalrus]

Kyle in answer to your question above- I believe that the .sc after .bgeo is a compression algorithm and is ok to have. I would make sure you have $F4 somewhere in your file name so you have clearly delineated sequence numbers, eg.  cache.0001.bgeo, cache.0002.bgeo  etc.

 

As for your other remark about learning it, I am also suffering tremendously from this dearth of learning materials!  I've been playing with Houdini for a couple years now, and recently started using it in a professional capacity, and I'm finding the learning is driving me NUTS! Not only is it the most complex prorgam to learn - harder than Maya in my opinion - but a lot of the tutorials, and even the documentaion, refer to older versions of Houdini, which are now completely obsolete!!! It drives me nuts when I just start to grasp the nodes used in a tutorial, to find they have been completely replaced or moved in H14.... 

 

This forum has been a life-saver in that regard.  THANKS FORUM PEEPS!

[Fostertron]

Thanks again Cameron,

 

I can't thank the people on this forum enough for the help I've received. Tbh, without odforce, I think it would be near impossible to learn Houdini. Even with all the tutorials, there are many gaps that need to be filled in for beginners like me. 

 

Although, I expect I'm just not as clever as most people here!

 

Have you any thoughts on boat tank/ocean compositing Cameron?

 

Thanks again

[cwalrus]

I used Maya's ocean shader when I needed to do this previously, and a funky plug in for the foam and spray - the name of which escapes me - to create stuff like this

for reality tv. 

 

I'd totally use Houdini's stuff now - very excited to check out it's wave/foam stuff when i have a chance

[Atom]

As far as mixing the two sims fluids together I asked a similar question here. The answer ended up modifying the HDA to accomplish the goal. Maybe it could work with merging the tank and the ocean too?

http://forums.odforce.net/topic/22089-fluid-tank-fluid-from-object-interaction-fill-tank/

[Fostertron]

Hi Atom,

 

Thanks again for your replies. I thought you'd be sick of my lack of knowledge by now. 

 

I think what you've suggested is a more complex solution than I need. My question wasn't clear but I expect you understood it anyway. 

 

All I want is to make the tankfluid look like the ocean waves that I'm matching it to. So I'll have 2 animation sequences, one of the splash tank and one of the oceanwaves. I'll then composite the 2 animations in Nuke. 

 

The last piece of the puzzle is making the tankfluid look like the waves (using Mantra). From what I can see, the oceanwaves consists of a wafer thin surface (displaced with maps) with the oceansurface shader assigned to it. This is then followed by an extrustion with the ocean volume applied to it. 

 

Do I need to emulate this to make it work? As in extract the top surface of the tank fluid and create an extrusion from this?

 

Here's an example of the body of water from Mantra:

 

 

 

 

I hope its not frowned upon but I'll put this question as a new thread since I think it's not specific to this thread. 

 

Thanks again

 

Kyle