MAYA_ Posted June 16, 2018 Share Posted June 16, 2018 Hello people of Houdini! I am having a problem and I am struggling to find a solution. I simulated some points, they start of as a small number and accumulate over time. Now, I want each point to have a unique point number. Normally, when dealing with a changing point number, I create an ID attribute at frame one. But so far, I have only ever encountered scenarios where the points got less and less over time, not more and more. I am not sure how to approach this and it is driving me crazy. I don't really want to resimulate my points and turn off the spawning over time, but I need to keep track of which point is which. If someone has an answer to this issue, I am super grateful for any input. Thank you so much in advance! Quote Link to comment Share on other sites More sharing options...
bonsak Posted June 16, 2018 Share Posted June 16, 2018 Could you reverse your sim and write the IDs from the last frame all the way through to the first frame. Save that to disk and reverse it again when you read it back in. That should give you consistent IDs. -b Quote Link to comment Share on other sites More sharing options...
davpe Posted June 16, 2018 Share Posted June 16, 2018 check out this video... around min 14. cheers Quote Link to comment Share on other sites More sharing options...
MAYA_ Posted June 16, 2018 Author Share Posted June 16, 2018 1 hour ago, davpe said: check out this video... around min 14. cheers Hi, thank you! But I think you forgot to attach the link Quote Link to comment Share on other sites More sharing options...
MAYA_ Posted June 16, 2018 Author Share Posted June 16, 2018 1 hour ago, bonsak said: Could you reverse your sim and write the IDs from the last frame all the way through to the first frame. Save that to disk and reverse it again when you read it back in. That should give you consistent IDs. -b Yes, I could. It is a bit painful but defiantly an idea thank you! Quote Link to comment Share on other sites More sharing options...
davpe Posted June 16, 2018 Share Posted June 16, 2018 heh, sorry 1 Quote Link to comment Share on other sites More sharing options...
MAYA_ Posted June 17, 2018 Author Share Posted June 17, 2018 4 hours ago, davpe said: heh, sorry Oh wow, thank you so much! This does the trick Quote Link to comment Share on other sites More sharing options...
ZMARDINI Posted October 18, 2021 Share Posted October 18, 2021 (edited) On 16/06/2018 at 9:06 PM, bonsak said: Could you reverse your sim and write the IDs from the last frame all the way through to the first frame. Save that to disk and reverse it again when you read it back in. That should give you consistent IDs. -b can you explain how would I go about doing this ? took the last frame and added ids, but could not figure out how to copy these ids to interpolating geometry, something to do with a solver sop no ? cheers! Edited October 18, 2021 by ZMARDINI Quote Link to comment Share on other sites More sharing options...
Atom Posted October 21, 2021 Share Posted October 21, 2021 I typically turn off reaping, which is what reuses point numbers and gums things up. This means all your particles will never die, and have a unique ID, assuming there is no point replication taking place. This doesn't invalidate the @dead attribute. So I let particles spawn, then after the popnet run a wrangle to remove any dead ones. 1 Quote Link to comment Share on other sites More sharing options...
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