breadbox Posted November 29, 2012 Share Posted November 29, 2012 Im wondering if its possible to retime a simulation cache Per Particle. so that I can offset the time of a region of particles but not another region. Ideally could control this with a falloff attribute. so If i colored gave all the particles in a region a red color based on the red color would control how many frames forward or back in time each particle was in time. hopefully I have explain that well enough. Quote Link to comment Share on other sites More sharing options...
Annon Posted November 29, 2012 Share Posted November 29, 2012 You can use a mix node in a vop sop. I've made you a quick scene using a grid with two different positions in Y, which are blended between the two using the red colour (altered by a ramp parameter). Obviously you're going to have to take changing point numbers into account with ID's etc, but I think this technique would work for you... Christian mixPos.hip Quote Link to comment Share on other sites More sharing options...
breadbox Posted November 29, 2012 Author Share Posted November 29, 2012 (edited) Thats a great example thanks, I think I'm trying for less of mixing between pos-A and pos-B and more of a retiming effect where each particle/point ID would get a frame value assigned to it based on a color or other attribute. maybe a way through chops? I guess it might be lag based on point color? although now that I think about it, this could get super slow with a simulation of around 500K points. Edited November 29, 2012 by breadbox Quote Link to comment Share on other sites More sharing options...
Annon Posted November 29, 2012 Share Posted November 29, 2012 Well yes but if instead of moving the points like I did you retimed them, left being normal, right being slower/faster, then blended between the point positions, you'd have what you want. But you could also use chops (slow on large particle counts). You might also be able to give each point an attribute and use that in the time offset ($F * $HOWMUCH) etc.. Quote Link to comment Share on other sites More sharing options...
breadbox Posted November 29, 2012 Author Share Posted November 29, 2012 (edited) yea after trying it a bit this method works pretty well and is really fast. I tried it out on a Houdini simulation and that works out because the point numbers are not changing per frame. with a real flow simulation however the point number changes on every frame yet the point ID stays consistent, so i'm trying to sort them based on the ID. in the sort sop I'm trying this: point("../NULL", $PT, ID, 0) but its not quite working. EDIT: opps its this point("../NULL", $PT, id, 0) doh! Edited November 29, 2012 by breadbox Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.