vbk!!! Posted November 16, 2009 Share Posted November 16, 2009 Hello, I begin to learn Houdini and, of course, I have some question to achieve a specified task ! I watched the tornado and sprite shader tutorial from 3dbuzz. I made my own tornado sim and procedural sprite surface shader. I include parameters to my shader to allow me to change it easely. I have still some problems importing attributes in vop shop. In the file attached ( simple particle emission), I try to make some changes in the color of my sprite using attribute like speed spritescale or life ... It works fine with speed, spritescale, Cd or Alpha. But I failed using the life attribute. Is it because it's not a float and not a vector ? I watch and rewatch my scene. I don't what I miss Thanks for your help sprite04.hip Quote Link to comment Share on other sites More sharing options...
itriix Posted November 16, 2009 Share Posted November 16, 2009 hi there, the LIFE variable is not actually "local" inside of SOPs and if brought in to VOPs it's actually life[0] and life[1], where life[0] is the amount of time you're particle has been alive, and life[1], is the amount of time you're particle can live... Therefore in order to get the "LIFE" variable you're thinking of, you have a couple options here: in VOPs, divide life[0]/life[1] to get you're LIFE or in SOPs, lay down an attributeCreate SOP, set it to TYPE FLOAT and POINT, and then in the value1, use $LIFE... then for the name you can either override this, by calling it life, or make you're own "newlife"... then in VOPs, reference this "newlife" var. Cheers, and g'luck Jonathan Quote Link to comment Share on other sites More sharing options...
vbk!!! Posted November 17, 2009 Author Share Posted November 17, 2009 Thank for the reply Jonathan, If the first option is possible in vopsop, is no more possible in vopshop. The global panel doesn't contain any life param. I tried the second option but regarding your post i think i made a mistake filling the attributeCreate node. The strange thing is, when I use the life attribute like I do with speed or Cd, NOTHING happen. I excepted a wrong result, something crazy but something. Quote Link to comment Share on other sites More sharing options...
vbk!!! Posted November 18, 2009 Author Share Posted November 18, 2009 i create a new attribute like you said Itriix It works fine. I just forget to update my cache to make the change effective (!) Thanks for your help Quote Link to comment Share on other sites More sharing options...
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