edgem Posted January 5, 2015 Share Posted January 5, 2015 (edited) Hello guys, I am trying to generate air bubbles underwater through a fish mouth. Is it doable with POP ? Does anyone have any idea on how to do it with POP solver inside houdini ? Have been messing with pop force but not achieving the required result... Thanks a lot Edited January 5, 2015 by edgem Quote Link to comment Share on other sites More sharing options...
paxsonsa Posted January 5, 2015 Share Posted January 5, 2015 Its very doable with POPs! These may help you: http://forums.odforce.net/topic/15486-bubbles/?hl=bubbles http://forums.odforce.net/topic/18754-bubbles/page-2?hl=bubbles If you want to use pops its just going to be an instancing problem on how to get the look and the merging, these may help as well: http://www.cs.ubc.ca/~kueck/papers/SimulationAndRenderingOfLiquidFoams.pdf http://graphics.ucsd.edu/~iman/SoapBubbles/soap_bubbles_2.pdf Cheers! Quote Link to comment Share on other sites More sharing options...
edgem Posted January 5, 2015 Author Share Posted January 5, 2015 (edited) Thanks for the reply. Well now the brief has changed, it has become underwater bubbles instead of air bubbles... I managed to get something from the sim though but like you said, the biggest diffuculty is to merge the geo and my math is not very good... I have just instanced simple sphere and I am looking to do something more complex while stamping with different radius scale Is there any way to get some sort of lattice on the sphere to deform over time ? So as to make it look more organic (I would use that as a model) How can I do it ? Thanks people Edited January 5, 2015 by edgem Quote Link to comment Share on other sites More sharing options...
paxsonsa Posted January 5, 2015 Share Posted January 5, 2015 For the geo merging it might be simply enough to use VDB. - Convert Bubble geo to vdb - In the intersection area the volumes should merge smooth - convert back to mesh and you should get something 'like' the way bubbles merge. Maybe..I am just spit balling. what type of deformation are you thinking? I would think a simple lattice before you copy onto the points would be good then stamp some value from the copy sop if want some simply squash and stretch (a transform would do the same) Why not try some noise on a vop sop as well? Quote Link to comment Share on other sites More sharing options...
edgem Posted January 6, 2015 Author Share Posted January 6, 2015 (edited) Yes that's what I am looking for. That nice squash and stretch deformation. Edited January 6, 2015 by edgem Quote Link to comment Share on other sites More sharing options...
j00ey Posted January 6, 2015 Share Posted January 6, 2015 In case it's the sort of thing you're looking for, I made these bubbles - http://tmblr.co/Z3KK8u1Z0tQ1t with a similar setup to what Paxsonsa suggests. If I remember correctly I had 2 sets of deformations going on. First I instanced a sphere with a lattice to flatten the leading side of the bubble in the direction of travel and push the back inwards [a bit like a red blood cell on the back side]. The faster moving and the larger the particle, the greater the deformation. Then I converted the whole geometry to a vdb and used some noise to displace it, to get some wobbly motion in the surface. 1 Quote Link to comment Share on other sites More sharing options...
edgem Posted January 6, 2015 Author Share Posted January 6, 2015 (edited) yes that's exactly how I would like to do. Do you still have the example file for the deformation ? The faster moving and the larger the particle, the greater the deformation. How would you tackle that ? Edited January 6, 2015 by edgem Quote Link to comment Share on other sites More sharing options...
j00ey Posted January 6, 2015 Share Posted January 6, 2015 I don't have the file I'm afraid but I'll make a demo file when I have a few mins later on Quote Link to comment Share on other sites More sharing options...
edgem Posted January 6, 2015 Author Share Posted January 6, 2015 thanks j00ey Quote Link to comment Share on other sites More sharing options...
j00ey Posted January 6, 2015 Share Posted January 6, 2015 No problem. Here you go. I've put in a couple of notes but it's not very complicated. Someone else might know a more elegant method... bubbles_deformation.hipnc Quote Link to comment Share on other sites More sharing options...
edgem Posted January 6, 2015 Author Share Posted January 6, 2015 I will have a look. Thanks Quote Link to comment Share on other sites More sharing options...
edgem Posted January 7, 2015 Author Share Posted January 7, 2015 Might I ask you what the VDB analysis is for ? Quote Link to comment Share on other sites More sharing options...
j00ey Posted January 7, 2015 Share Posted January 7, 2015 That's to calculate the closest point transform, which is the correct method to displace VDBs according to one of the example files here - http://www.openvdb.org/download/houdini_examples.hip.zip I'd recommend having a look through all the examples in there, very useful stuff. 2 Quote Link to comment Share on other sites More sharing options...
edgem Posted January 7, 2015 Author Share Posted January 7, 2015 thanks j00ey. Very useful link Quote Link to comment Share on other sites More sharing options...
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