Lee Jackson Posted May 8, 2015 Share Posted May 8, 2015 Hey there everyone, I'me relatively new to Houdini, but I've been trying to create a river that I can have an animated quadruped erupt out of. However I can't get my particles to slow down. They rush through my river bed and look far too destructive. Does anyone have a simple fix for this, I'm sure there is one and I've just missed it. Thanks. Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 You can add drag or change timescale. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 You can add drag or change timescale. does that just slow the speed of the entire sim? Effectively like applying slow motion? Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 Increase Smoothing parameter under Volume Motion tab. Decrease collision bounce and Velocity Scale. Increasing Surface Extrapolation might help too. Changing these parameter will create less splash and Velocity Scale will help in shooting. Quote Link to comment Share on other sites More sharing options...
Netvudu Posted May 8, 2015 Share Posted May 8, 2015 Yes.Changing the timescale will look like slo-mo. The only problem is that it will affect the look of your simulation. So if you have a quick one that you like, you cannot just change the timescale and expect the same result but slower. Another option, if you can change it in advance is to alter the frames per second of your scene. I like this as it´s similar to recording with a high-speed camera. Pradeep mentioned some parameters that can also help in achieving a smoother-looking sim. If you already simulated but want to change it to slo-motion then you´re going into the the very "thorny" topic of retiming simulations. For that be sure not to re-seed particles during your simulation and then you can use your time blend and time shift tools on a cached sim to change the pace of your particles. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 Increase Smoothing parameter under Volume Motion tab. Decrease collision bounce and Velocity Scale. Increasing Surface Extrapolation might help too. Changing these parameter will create less splash and Velocity Scale will help in shooting. Hmm, after trying to alter these parameters, I got little to no change in the speed of my river. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 Yes.Changing the timescale will look like slo-mo. The only problem is that it will affect the look of your simulation. So if you have a quick one that you like, you cannot just change the timescale and expect the same result but slower. Another option, if you can change it in advance is to alter the frames per second of your scene. I like this as it´s similar to recording with a high-speed camera. Pradeep mentioned some parameters that can also help in achieving a smoother-looking sim. If you already simulated but want to change it to slo-motion then you´re going into the the very "thorny" topic of retiming simulations. For that be sure not to re-seed particles during your simulation and then you can use your time blend and time shift tools on a cached sim to change the pace of your particles. I don't won't to play with the speed of the simulation as I plan on having an animated object erupt out of it once I get the speed of the river sorted, I don't want to mess with the look of the breach. Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 Post your file. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 Post your file. just trying to work out how to now, new to this forum sorry. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 Here we go. River_1.hip Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 (edited) Here we go. There is no NewRiverBend.obj included. Lock it or upload it separately. Edited May 8, 2015 by pbarua Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 (edited) There is no NewRiverBend.obj included. Lock it or upload it separately. Woops, I'm trying to do things too fast. I'll upload now. NewRiverBend.rar Edited May 8, 2015 by Lee Jackson Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 (edited) Why did you place emitter in the air? Place it on ground and reduced or zero out RBD's Bounce. Edited May 8, 2015 by pbarua Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 And give some velocity to your emitter in negative Z -axis. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 Why did you place emitter in the air? Place it on ground and reduced or zero out RBD's Bounce. Learn something new every day. Pretty new to houdini, loving it so far though. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 And give some velocity to your emitter in negative Z -axis. When you say ad velocity, are we talking the initial velocity inside the flipfluidobject? Quote Link to comment Share on other sites More sharing options...
pbarua Posted May 8, 2015 Share Posted May 8, 2015 You can add it at SOP level in Fluid Source SOP under Velocity Volumes. Quote Link to comment Share on other sites More sharing options...
Lee Jackson Posted May 8, 2015 Author Share Posted May 8, 2015 Will have to have a look soon, just baking out a few hundred frames to see what it's looking like. Quote Link to comment Share on other sites More sharing options...
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