Pazuzu

Unfortunately that's one of the limitations of the FLIP method, the volume loss. As Andrew said a particle separation can help to cont-rarest the volume loss on the system. You can try also to apply some drag forces as soon as the fluid start to settle with some speed or pressure conditions, but that can kill a bit the nice momentum. For this kind of FX I really miss SPH, but its so slow; So in my case I come around to this problem using a mix between PBD and FLIP/PIC in my microtension tools, this way the volume loss is less noticeable, but still not as good as the SPH method, I really hope that SESI update some of the SPH microsolvers some day!. I hope that this helps you! Cheers! Alejandro

Hi, Here is an approach to accumulate scatter using a for block, I know that is a bit cumbersome, but maybe there is a much better way. Cheers! Alejandro scatterAcum.hip

Yes, its just a static mask, because the field is overridden on every timestep as the relationship is active, but you can use that mask to source into a dynamic field (Density, Divergence, Temperature, Fuel, etc). Cheers! Alejandro

If you want to find even more details of the amazing surfacepressure implementation in the FLIP solver, look at the second edition of the "Fluid Simulation For Computer Graphics" book!! Is amazing!!! Cheers! Alejandro

The Smoke object is just the container of data (In DOPs is very important that you have a container where all the data will be for DOPs to process) that contains all the necessary fields that the smoke/pyro solver will use to make the sim evolve by the DOPs engine. In the file you will find two main colors to identify the relationship type, there are two in this case, a source relationship (green) and a sink relationship (red). So all the colored nodes makes each relationship works, for example for the source one, you need a merge DOP that will define the type or relationship as a source, then you need the object to generate the mask from (sphere) and finally the microsolver that will generate the mask field for your relationship (gasbuildrelationship__source). Regards the "reference field density", is a parameter of the node to generate the mask as a "fog" field, by default the node creates SDF representations. Cheers! Alejandro

This microsolver helps you to define a field mask using standard DOPs relationships (using the merge DOP for example). You can define for example a source object mask to emit fuel or density using just relationships, so if you have many objects and connect those besides the smoke solver with a merge using source relationship mode, the gasbuildrelationshipmask will create a field representing the objects as a fog or SDF representation. Attached is an example file (one hip is better that a thousand words ) Cheers Alejandro gasbuildrelationshipmask.hip

Ohhh Man I don't think so!! So much to learn still! DOP context is like a black Hole full of Chaos and Alternate Possibilities! Cheers!!

You can control the pressure jump per particle with a scalar field as a factor for the surface-pressure field. Attached is a very raw example of it. I hope that helps! Cheers Alejandro pp_st.hip

I think that you can simplify even more the code:

Thanks for the info! Its possible to apply also as a remote worker? Or It should be in London? Thanks Alejandro

Sure you can! The nice thing about pyro is that the combustion model is a post computation (but by default you can't accumulate divergence aka "Gas Release", because there is a cleaning before the combustion model), so you can create an ad-hoc scalar field to then sample your age out of your particles to use as a factor for the divergence to control the expansion/contraction of your sim in a per particle basis. But I think also that the divergence is not the only problem, I think you should also control or force the fuel to die with the same "age" field, to have even more control or shaping of your sim. Cheers! Alejandro

One think that the diffusion filter misses right now is that it doesn't take into account the time increment of the system; But that can easily be implemented with a blended average technique in that sop solver. Cheers! Alejandro

No Problem! Here is an example for diffusion and dissipation as the material gets closer to the collision object. I hope that this helps! Cheers! Alejandro dissipation_by_collision_proximity.hip

The pcopen just give you a handle with the points sampled at a given radius; Then you can use another pc function like pcfilter to average the result of some data over the handle points, or you can use some pc combo functions like pciterate-pcimport to construct a loop over the handle. The pc arsenal is very usefull and is faster in some cases than using arrays. Cheers! Alejandro

Nice changes! You don't need to define a new divergence volume if you want the divergence to work as it should. You only need to activate the field in the flip object, then define the divergence attribute on the particles directly. Regards filling faster, you can use the same rules for the collisionWeights to define the divergence and help the fluid gain volume when is inside the collision object, also you can create particles on demand when the fluid expands, so you can use reseeding for this or create your own dynamic setup for on demand particle generation. Here is a mod to the Jim's file that shows that, it will became unstable at the end mainly because of the volume gain, but you can animate the reseeding toggle and kill the divergence, or test the fluid volume against the volume of the collision object to deactivate the expansion, a more procedural solution. Finally one limitation on this collision weight technique is that if you use so much extrapolation the fluid will escape at the zone where the fluid stream is flowing, all of this is because of the fluid reconstruction with the gas particle to field. Hope that helps! Alejandro ap_collisionWeights_v001_jlim_FasterFilling.hiplc

You can create an ad-hoc field out of your collision field, or make it directly in sops using your collision field. So you can extrapolate from the iso-contour to construct a mask to control a dissipation filter when the density is in proximity. I hope that this helps! Alejandro

You're Welcome!!

collisionWeights_v001.hip

Here is the scene file that shows how to manipulate collision weights for an explicit control (rules) of how your particles collide. Enjoy! Alejandro

Its all about playing with collision weights! This is totally possible! I did a modification to the Flip solver to do exactly this a year ago. I'll try try to search the file and send you an example. But basically you should do manipulate the collision weight per particle to control the collision behavior. So with just a simple rule like sampling the collision SDF you can test if you want to turn on or off your collision weight to let the particles collide or not with the objects boundary. Cheers! Alejandro

Hi Huge! Please look at this tutorial that Ben Watts did sometime ago using my technique, is very very simple but powerful. Cheers!

I think you can give speed variation to the propagation using a per point factor of aggregation on each iteration. That can give you faster or slow zones of accumulation, then you can use that factor to grow your instances in a more smooth way. I hope that this helps! Cheers!

Really Nice Pavel! Thanks for sharing this!!!

Here is a little correction to preserve your original fracture position. Cheers! Constraint Obj Test 02.hipnc

More love to the small scale fluid pipeline (Rewriting of SPH solver and related microsolvers) New methods for the gas pipeline (incompressible Schrödinger flow for example)