angadrana 1 Posted April 9 Hey guys, I'm trying to make a missile go very fast in Houdini. I have a missile model and a sphere parented to it as the emitter. I'm using the Billowy smoke shelf tool. The problem is that when it goes fast, the smoke is in the shape of a sphere and far apart from each other . How can I make a really good looking smoke trail behind it with the smoke trail/ billowy smoke preset when it's going really fast? I'm pretty new to Houdini. Can someone please help me? Share this post Link to post Share on other sites
StepbyStepVFX 42 Posted April 9 Try increasing the number of substeps of your simulation, on the DOP node itself. Don’t forget that a simulation works in « discrete » amount of time - the solver don’t « evaulate » your missile in between frames -, so if your missile goes too fast, you will only see isolated sources of smoke. That’s why you need to tell the solver to look also between frames : substeps are meant for that :-) Given your image, try at least 4 substeps I would say (but you will increase simulation time by 4 :-) If you want to know more about simulation, a great MOOC is here : https://www.edx.org/course/animation-cgi-motion-columbiax-csmm-104x-2 Share this post Link to post Share on other sites
cudarsjanis 39 Posted April 9 4 hours ago, StepbyStepVFX said: Try increasing the number of substeps of your simulation, on the DOP node itself. Don’t forget that a simulation works in « discrete » amount of time - the solver don’t « evaulate » your missile in between frames -, so if your missile goes too fast, you will only see isolated sources of smoke. That’s why you need to tell the solver to look also between frames : substeps are meant for that :-) Given your image, try at least 4 substeps I would say (but you will increase simulation time by 4 :-) If you want to know more about simulation, a great MOOC is here : https://www.edx.org/course/animation-cgi-motion-columbiax-csmm-104x-2 That course is looks great! Have you done it already? Cheers Janis Share this post Link to post Share on other sites
cudarsjanis 39 Posted April 9 7 hours ago, angadrana said: Hey guys, I'm trying to make a missile go very fast in Houdini. I have a missile model and a sphere parented to it as the emitter. I'm using the Billowy smoke shelf tool. The problem is that when it goes fast, the smoke is in the shape of a sphere and far apart from each other . How can I make a really good looking smoke trail behind it with the smoke trail/ billowy smoke preset when it's going really fast? I'm pretty new to Houdini. Can someone please help me? As mentioned substeps will help you out. Also you can try motion blur on fluid source node. So your source is already like smoke trail. that would fill up the gaps as well. Mix it up with some substeps and you`re good to go. Share this post Link to post Share on other sites
StepbyStepVFX 42 Posted April 9 5 minutes ago, cudarsjanis said: That course is looks great! Have you done it already? Cheers Janis I am still following it, you can download the video (very nice to watch them in the subway :-), but of course I can’t code). Anyway, that’s more for my pleasure : if you have studied physics and did a bit of maths, there is nothing new :-) By the way, teacher is great (i think he made is phd or post doctoral studies at Weta or something like that). 1 Share this post Link to post Share on other sites
angadrana 1 Posted April 9 Thank you so much guys! I really appreciate it! Share this post Link to post Share on other sites
Midasssilver 1 Posted May 4 A cheaper way to resolve source stepping without resorting to substeps is having a trail on your source points/surface before the fluid source. This will make the source itself longer, filling in those gaps without the need for substeps. A blend of a trailed source, and some amount of substeps might be necessary, but this should help. Share this post Link to post Share on other sites
