Pancho Posted June 20, 2017 Share Posted June 20, 2017 Am I the only one who seems to experience flip fluid movement due to surface tension on high viscosity fluids? Viscosity is set to 100.000, object size about 5cm (0.05 units) and tension is set to 1. The details disappear rather quickly and the surface gets smoother. THis shouldn't happen with such a high viscosity. Can I override the surface tension per particle, since the viscosity changes on a per particle basis? H16 here with the new surface tension in the solver. Cheers Tom Quote Link to comment Share on other sites More sharing options...
chrisdunham95 Posted June 20, 2017 Share Posted June 20, 2017 Perhaps you could interlink the viscosity and surface tension using custom attributes - Or have the surface tension directly derive from the viscosity or the opposite way - Will post a file later if i get chance! Quote Link to comment Share on other sites More sharing options...
Guest tar Posted June 20, 2017 Share Posted June 20, 2017 On 6/20/2017 at 12:38 PM, Pancho said: THis shouldn't happen with such a high viscosity. Expand Based on what? Quote Link to comment Share on other sites More sharing options...
Pancho Posted June 20, 2017 Author Share Posted June 20, 2017 Well, if you want to melt something in H16 and it turns into a liquid it shouldn't deform before changing from its solid state into a liquid one. The way to do this a.f.a.i.k. is to use high viscosity and then change it to something lower. Quote Link to comment Share on other sites More sharing options...
Guest tar Posted June 20, 2017 Share Posted June 20, 2017 Do you have a test file that shows this? Simple tests here don't show any movement with high viscosity and surface tension. Surface tension attributes aren't in H16, you should be able to build it though with a GasToParticle and a new field IIRC. Quote Link to comment Share on other sites More sharing options...
chrisdunham95 Posted June 21, 2017 Share Posted June 21, 2017 On 6/20/2017 at 6:22 PM, marty said: Do you have a test file that shows this? Simple tests here don't show any movement with high viscosity and surface tension. Surface tension attributes aren't in H16, you should be able to build it though with a GasToParticle and a new field IIRC. Expand Their are new surface tension control and attributes in H16 within the flip solver itself, how accurate etc it works i dont know but pretty sure it is their Quote Link to comment Share on other sites More sharing options...
Guest tar Posted June 21, 2017 Share Posted June 21, 2017 On 6/21/2017 at 11:15 AM, chrisdunham95 said: Their are new surface tension control and attributes in H16 within the flip solver itself, how accurate etc it works i dont know but pretty sure it is their Expand Hmmm - not sure why you think there is an attribute for surface tension, because.. ta da.. there isn't! Quote Link to comment Share on other sites More sharing options...
Pazuzu Posted June 21, 2017 Share Posted June 21, 2017 On 6/21/2017 at 10:39 PM, marty said: Hmmm - not sure why you think there is an attribute for surface tension, because.. ta da.. there isn't! Expand 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 2 Quote Link to comment Share on other sites More sharing options...
Guest tar Posted June 22, 2017 Share Posted June 22, 2017 @PazuzuBoom! master DOP magician Quote Link to comment Share on other sites More sharing options...
Pazuzu Posted June 22, 2017 Share Posted June 22, 2017 On 6/22/2017 at 12:24 AM, marty said: @PazuzuBoom! master DOP magician Expand 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!! 1 Quote Link to comment Share on other sites More sharing options...
chrisdunham95 Posted June 22, 2017 Share Posted June 22, 2017 On 6/21/2017 at 10:39 PM, marty said: Hmmm - not sure why you think there is an attribute for surface tension, because.. ta da.. there isn't! Expand this is what i am referring too; Quote Link to comment Share on other sites More sharing options...
Guest tar Posted June 22, 2017 Share Posted June 22, 2017 On 6/22/2017 at 4:03 PM, chrisdunham95 said: this is what i am referring too; Expand right - so how do you define that control to have more surface tension in low viscosity vs high viscosity areas? Quote Link to comment Share on other sites More sharing options...
Dave Stewart Posted June 22, 2017 Share Posted June 22, 2017 Pazuzu's file, slightly modified, would let you drive the surface tension field values based on a point viscosity attribute or whatever. Makes for some interesting shaping by the end! See attached modded file... --Dave pp_st_ds.hip 4 Quote Link to comment Share on other sites More sharing options...
chrisdunham95 Posted June 23, 2017 Share Posted June 23, 2017 On 6/22/2017 at 7:36 PM, marty said: right - so how do you define that control to have more surface tension in low viscosity vs high viscosity areas? Expand Im not sure but my point was their is a surface tension attribute in the new h16 Quote Link to comment Share on other sites More sharing options...
Guest tar Posted June 23, 2017 Share Posted June 23, 2017 On 6/23/2017 at 10:31 AM, chrisdunham95 said: Im not sure but my point was their is a surface tension attribute in the new h16 Expand That Surface Tension control is a 'parameter' - totally different to an 'attribute' in Houdini. Quote Link to comment Share on other sites More sharing options...
myke3d Posted July 4, 2017 Share Posted July 4, 2017 On 6/22/2017 at 10:54 PM, Dave Stewart said: Pazuzu's file, slightly modified, would let you drive the surface tension field values based on a point viscosity attribute or whatever. Makes for some interesting shaping by the end! See attached modded file... --Dave pp_st_ds.hipFetching info... Expand That's super awesome. Thanks Dave and lord Pazuzu... you guys are TOP Quote Link to comment Share on other sites More sharing options...
eetu Posted July 4, 2017 Share Posted July 4, 2017 On 6/23/2017 at 6:27 PM, marty said: That Surface Tension control is a 'parameter' - totally different to an 'attribute' in Houdini. Expand Well, yes and no. It's a field in the flip solver so you can vary it by voxel, like Dave/Pazuzu did above. Conceptually I would regard it to be closer to an attribute than a parameter, even though you would need a spoonful of extra noodle soup to source it from a point attribute. The name is surfacepressure not surfacetension, but don't let it fool ya ;) Quote Link to comment Share on other sites More sharing options...
Pazuzu Posted July 4, 2017 Share Posted July 4, 2017 (edited) 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 Edited July 4, 2017 by Pazuzu 3 Quote Link to comment Share on other sites More sharing options...
Dave Stewart Posted July 4, 2017 Share Posted July 4, 2017 Here's another version using PopVop/GasFieldVop instead of wrangles... hope it helps clarify the process! Set this up *very* quickly so let me know if I missed anything. Should be able to drive the surfacepressure field directly from the viscosity field, but the values would probably need adjusting in the 'fit' node. --Dave pp_st_ds_PopVOPs.hiplc Quote Link to comment Share on other sites More sharing options...
Guest tar Posted July 4, 2017 Share Posted July 4, 2017 On 7/4/2017 at 10:55 AM, eetu said: Conceptually I would regard it to be closer to an attribute than a parameter, even though you would need a spoonful of extra noodle soup to source it from a point attribute. Expand it's simply a matter of the degree of generalisations and context here.. e.g. hey you call that a number! it actually an element of a field, a scalar, a coordinate, a component, a matrix and a vector. Quote Link to comment Share on other sites More sharing options...
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