FLIP - emit from particles and propper collisions

[borisb2]

Hi.

 

to create more interesting secondaries (than just ballistic) I'm trying to emit from whitewater-source into a new Flip-sim. Inside DOP I'm using standard source-volume for emission. This kind of works but creates little streaky shapes .. not sure if thats the propper way to emit Flip from particles?

 

Would it be better to convert the WW-points to a new surface-field and source from that instead? .. or more general, whats the best way to emit from any kind of POP-network into a Flip-Sim?

 

About collision:

since this setup is for secondaries I still need to let them collide with the base sim. For that I am using in DOP a static-object, set to proxy-volume, that pulls the surface-field from the base-sim. This seems to work fine for collision and also hase "some" velocities in the right direction but this new sim looks more floating on top of the base sim, rather than traveling with it (its a riverbed). Is it not getting the vel-field form the base sim that way? What would be a better way to setup collisons with flip?

 

Thanks a lot

[danw]

This may not be much help, but I'm not sure emitting fluid from a fluid will get you very far.  The idea of secondaries is to approximate details too fine to be represented by the limited resolution you can manage in a genuine fluid simulation.  Whitewater is treated as a simple ballistic particle simulation so that you can chuck out masses of tiny particles and inherit the motion onto them from a pre-solved, lower resolution fluid.

Two fluid simulations riding on top of one another would almost certainly be better as just a single combined fluid sim, otherwise they probably will appear strange.  You can't really enforce a previous sim's velocity onto a secondary fluid simulation, as fluid has to respect a pressure solve, and generates its own velocities as a result.  You can only really enforce pre-calculated velocities (and thus "match" the behaviour between sims) by advecting "dumb" particles around.

 

Personally I'd suggest trying to get the most out of the whitewater system as it stands.  It's certainly not the perfect way, and there's always room for new ideas and techniques, but I also think there's plenty of mileage in the "official" setup, if you spend time working up the look.

[borisb2]

well yes and no .. I recall doing a lot of secondaries in Naiad as full Flip-sims, whether it was a geysire (where half of the geysire look was just secondaries), splashy waves or wakes etc... sure, doing a riverbed project the whitewater setup might be perfect .. but even there I was (and still am) struggeling a lot to get good moving secondaries .. as seen in my other thread here: http://forums.odforce.net/topic/20946-foam-and-spray/page-2

 

no idea, what I am doing wrong there. The foam/spray is moving in the right direction but the advection looks averaged, this looks more like ambient-mist then foam/spray (despite my foggy rendering test)

 

Realflow 2014 is very proud to finally add flip/sph for secondaries.

 

But you're right .. the ww-setup is a cool tool (as we had at mpc with flowline -> bubble turning into foam etc.) .. it just has to look good .. but thats maybe just my fault

[CeeGee]

Flip as secondarys are great to add realistic look,

 

this is some old test but you can see here flip as secondarys working great

 

http://www.igorfx.com/street_flood/street_flood_break.html

 

also just for foam, you can use wwater source for emition, and advect by volume from main flip solver this is simple and works more less ok, and add on top flip secondarys for splash

 

Igor

Edited October 7, 2014 by CeeGee

[michaelliu]

Igor,  i am your fans

 

can you give us some advice ,for  flip collision with the deform object ?  

 

like  this:

 

thank you !