bazza2534 Posted May 31, 2014 Share Posted May 31, 2014 Hi guys, I've created a particle simulation which will simulate perfectly fine in houdini view port and will render via mantra node fine up until frame 157. on frame 158, the render really grinds down slow. It also tends to suddenly blur the frame quite badly. I've tried disabling the particle color and other nodes which don't seem to make any difference. Since it renders 157 frames as it should, I don't understand why it would suddenly have an issue with frame 158 and beyond. Would this be a caching issue while rendering? Or maybe the mantra renderer itself? (I am using a PC but I've also tried it on a Mac -same version of houdini with the exact same result). Any help would be much appreciated. Cheers! B Quote Link to comment Share on other sites More sharing options...
Hello world Posted May 31, 2014 Share Posted May 31, 2014 chances are there if u have cached it only till frame 157.can u share the hip? Quote Link to comment Share on other sites More sharing options...
bazza2534 Posted May 31, 2014 Author Share Posted May 31, 2014 Even without a cache, it will still do it. I've attached the hip file. Cheers for ya help. particles.hip Quote Link to comment Share on other sites More sharing options...
bazza2534 Posted May 31, 2014 Author Share Posted May 31, 2014 I've been told that because the particles begin to die on frame 158, the trail node suddenly has to re calculate motion blur for the decreasing amount of particles (makes sense, And I hadn't even thought that at all). Cheers for your help! - B Quote Link to comment Share on other sites More sharing options...
Skybar Posted May 31, 2014 Share Posted May 31, 2014 (edited) Yes, by default the Trail SOP tracks each particle by point number. So when you kill off particles, the point numbers change and from the Trail SOPs point of view the particle have moved, even though it is an entirely different particle. This might lead to really big velocities and then of course insane motion blurring. Take a look at "Match by Attribute" on the Trail SOP. You'd have to find a way to give a unique ID per particle that doesn't change with the point count, that way it should be fine. edit: Didn't realize you were using a POPnet, in that case each particle is given an ID by default. So it should already be there for you to use. Edited May 31, 2014 by Skybar Quote Link to comment Share on other sites More sharing options...
mawi Posted May 31, 2014 Share Posted May 31, 2014 Why do you need a trail sop? Velocity attribute is already calculated in POPs. Quote Link to comment Share on other sites More sharing options...
bazza2534 Posted June 1, 2014 Author Share Posted June 1, 2014 That makes a lot of sense. Cheers guys, much appreciated. Quote Link to comment Share on other sites More sharing options...
mangi Posted June 1, 2014 Share Posted June 1, 2014 (edited) Hi Brayden. here is your sim, and I managed to get frame 158 rendering just fine now. No changes have been made in your project. Could you give it a render at your end and see if it is okay now. Cheers Mangi particles_render 158(RENDER_fix_Vel scale 8.62a).hipnc Edited June 1, 2014 by mangi Quote Link to comment Share on other sites More sharing options...
bazza2534 Posted June 1, 2014 Author Share Posted June 1, 2014 Cheers Mangi, Yea I just ended up disabling the trail node so I ended up rendering my project and added 100,000 extra particles just for the hell of it. Cheers for your help bro. - B Quote Link to comment Share on other sites More sharing options...
mangi Posted June 2, 2014 Share Posted June 2, 2014 Okay Brayden Glad to here you got it working . Cheers Mangi Quote Link to comment Share on other sites More sharing options...
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