Solitude Posted March 11, 2010 Share Posted March 11, 2010 Like the title says, is there a way to tell if a particle just entered a group? Basically I want to set velocity of a particle on one frame... only when the particle first enters a specific group. Any suggestions welcome Thanks! Quote Link to comment Share on other sites More sharing options...
Sayden Posted March 11, 2010 Share Posted March 11, 2010 Maybe you can use the same expression you'd use to get the particles into the group. For example, if particles are in group when $TY>1 then, in the velocity field write the same expression... Or you could write a python operator to compare the same group node at different frames... but I don't know exactly if it is possible or how... Lots of times errors comes because bad approximation to resolve a problem. Good luck! Quote Link to comment Share on other sites More sharing options...
Solitude Posted March 11, 2010 Author Share Posted March 11, 2010 You know, I didn't really think of that (pretty retarded of me!) -- but here's my issue, though I still have to test.. I am using a voppop to set the group based on a condition, but I'm still wrapping my head around vops, and how to get it to set a value once, and then have my particles keep that value, not have it overwritten every frame (right now I'm trying with color, though I'll try with velocity tonight). If I have time, I'll post a file tonight to better explain what I mean. Quote Link to comment Share on other sites More sharing options...
vi_rus Posted March 12, 2010 Share Posted March 12, 2010 Maybe something like this? =) new_in_group.hip Quote Link to comment Share on other sites More sharing options...
Solitude Posted March 12, 2010 Author Share Posted March 12, 2010 Maybe something like this? =) new_in_group.hip YES! That was it... and I kind of get it too! ...pretty simple, yet was such a pain for me to wrap my head around the logic (overall Houdini Pop logic) Thanks! Quote Link to comment Share on other sites More sharing options...
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