mentor Posted November 14, 2007 Share Posted November 14, 2007 (edited) I'm trying to make realistic snow in Houdini with particles and metaballs. But i've discovered some problems... I don't know how to make metaballs smaller at the end of branches... So, i need in good advices how to change metaball's radius towards the ends of branches I'm thinking how i can use bounding objects... Here is my latest test (rendered in 3dmax): How to make snow fluffy (larger metaballs) in the areas where i have many particles? And smaller metaballs near branch borders? Edited November 15, 2007 by mentor Quote Link to comment Share on other sites More sharing options...
MIguel P Posted November 14, 2007 Share Posted November 14, 2007 Nice So, i need in good advices how to change metaball's radius towards the ends of branches Maybe you can measure the polygon area and use it to modify the size. Quote Link to comment Share on other sites More sharing options...
michael Posted November 14, 2007 Share Posted November 14, 2007 not sure about getting smaller metaballs at the ends of branches...been a long day... but from the above image I don't think you really need to worry about it...that's what this kind of heavy wet snow looks like on spruce/pine etc... a better improvement might be to figure out a way to knock chunks off from random areas... keep up the good work Quote Link to comment Share on other sites More sharing options...
Dhiren Shah Posted November 14, 2007 Share Posted November 14, 2007 Gr8 start.Like it. Quote Link to comment Share on other sites More sharing options...
terze Posted November 15, 2007 Share Posted November 15, 2007 this was just a quick test but you can somewhat scale the metaballs with the stamp func from copy with $BBX Quote Link to comment Share on other sites More sharing options...
mentor Posted November 15, 2007 Author Share Posted November 15, 2007 Snx for help I think that measure SOP can't help me - actually i have very different polygon's areas, for example - long and thin one. I'm thinking about Bounding Box - but how to use this variables with rounded trees? With pine, spruce etc. So, i'm currently thinking about making low-poly envelope around my tree (bounding object) and calculating distance from this envelope to particles. For example - if particle located near my envelope (how to check this?) then metaball's radius has to be smaller. Another idea - to make envelope around main branches, group particles inside/outside and use this groups to modify the size. Quote Link to comment Share on other sites More sharing options...
rdg Posted November 15, 2007 Share Posted November 15, 2007 It all depends on how you generate your base geometry. though it might be possible i cannot reverse engineer this from your network screenshot. I'd try to isolate the branches as lines to scale the metaballs based on $PT. But this doesn't explain the popnetwork - does it "grow your snow"? Maybe there is something inside the popnet that can be used too. Georg Quote Link to comment Share on other sites More sharing options...
mentor Posted November 15, 2007 Author Share Posted November 15, 2007 I'm importing trees as meshes from Onyx TreeStorm Unfortunately i have only mesh. Quote Link to comment Share on other sites More sharing options...
loopyllama Posted November 15, 2007 Share Posted November 15, 2007 attrib transfer red from a simple geometry to your tree. use blend width and distance to control falloff. copystamp up the red to your metaball. use fit01 to remap red to your min and max metaball size. Quote Link to comment Share on other sites More sharing options...
mentor Posted November 15, 2007 Author Share Posted November 15, 2007 (edited) Great thanks! I made it!!! Edited November 15, 2007 by mentor Quote Link to comment Share on other sites More sharing options...
cellchuk Posted November 16, 2007 Share Posted November 16, 2007 Nice work I like it. :thumbsup: Quote Link to comment Share on other sites More sharing options...
mentor Posted November 16, 2007 Author Share Posted November 16, 2007 Another question! For example i have grid object, how i can procedurally select border's point or edges? Quote Link to comment Share on other sites More sharing options...
flowerdealer Posted November 16, 2007 Share Posted November 16, 2007 Use the divide SOP with Remove Shared Edges turned on? Got that from the On the spot book, (it's great by the way). Quote Link to comment Share on other sites More sharing options...
mentor Posted November 16, 2007 Author Share Posted November 16, 2007 Snx! And the last (i hope) question - i have small volumes of metabolls - how to delete them? Or delete small pieces of polygons? (i'm growing metabolls over them) Quote Link to comment Share on other sites More sharing options...
mentor Posted November 16, 2007 Author Share Posted November 16, 2007 I used Fuse SOP after Convert Meta to remove undesirable points Quote Link to comment Share on other sites More sharing options...
mentor Posted November 16, 2007 Author Share Posted November 16, 2007 (edited) Small udate Edited November 16, 2007 by mentor Quote Link to comment Share on other sites More sharing options...
michael Posted November 16, 2007 Share Posted November 16, 2007 good stuff! now lets see a forest! Quote Link to comment Share on other sites More sharing options...
Jason Posted November 17, 2007 Share Posted November 17, 2007 good stuff!now lets see a forest! And a Mantra render! Quote Link to comment Share on other sites More sharing options...
Jordan Posted November 17, 2007 Share Posted November 17, 2007 And a Mantra render! yea.. definitely a mantra version of this!!! I would like to see how far it can go. Quote Link to comment Share on other sites More sharing options...
mentor Posted November 17, 2007 Author Share Posted November 17, 2007 (edited) Rendering in mantra takes near 20 min! Its terrible! But i don't know how to improve render time, i'm novice in mantra In this scene i have 1.3 million vertices, raytraced shadows and Global Illumination (full irradiance, 32 samples) If i do renders with Global Illumination Matra renders 2 frames - 1st something white 256x256 and 2nd goes my picture. After turning off Global Illumination mantra doesn't render 1st white frame... Edited November 17, 2007 by mentor Quote Link to comment Share on other sites More sharing options...
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