jyh126 Posted May 30, 2019 Share Posted May 30, 2019 Hi all ! I'm trying to make a cloud collision effect using pyro solver. so I need totally stopped smoke simulation but drag force in dopnet doesn't work normally. It works very slightly. Smoke spreading speed get slower little bit but that's it. I tried another way to using timescale in pyrosolver. It looks like worked but collision effect doesn't work in slow time scale. How can I get a stopped smoke simulation with collision effect? thanks in advance!! Quote Link to comment Share on other sites More sharing options...
Andrea Posted May 30, 2019 Share Posted May 30, 2019 Hi! You can modify the velocity volumes your self using microsolvers such as gas linear combination, gas calculate or gas field wrangle. You can scale down the velocities manually and globally at a certain frame or use volumes as masks. Using masks is generally better because you can focus the effect on a specific area and leave everything else as it is. This mask volumes can be created in SOP context, created in DOP or from the fields of the pyro solver or combine them all! Quote Link to comment Share on other sites More sharing options...
jyh126 Posted May 31, 2019 Author Share Posted May 31, 2019 18 hours ago, Andrea said: Hi! You can modify the velocity volumes your self using microsolvers such as gas linear combination, gas calculate or gas field wrangle. You can scale down the velocities manually and globally at a certain frame or use volumes as masks. Using masks is generally better because you can focus the effect on a specific area and leave everything else as it is. This mask volumes can be created in SOP context, created in DOP or from the fields of the pyro solver or combine them all! hi Andrea! Thanks for your reply. I'm beginner to Houdini so don't know how to use gas linear combination, calculate etc. But I tried to use gas field wrangle and detected that if velocity is zero, collision doesn't work. Anyway I found a way to stop smoke using drag force assigned animation key in Activation. Thanks for your help again and I will use your tip someday! Quote Link to comment Share on other sites More sharing options...
char Posted May 31, 2019 Share Posted May 31, 2019 On 5/30/2019 at 8:41 AM, Andrea said: Hi! You can modify the velocity volumes your self using microsolvers such as gas linear combination, gas calculate or gas field wrangle. You can scale down the velocities manually and globally at a certain frame or use volumes as masks. Using masks is generally better because you can focus the effect on a specific area and leave everything else as it is. This mask volumes can be created in SOP context, created in DOP or from the fields of the pyro solver or combine them all! @Andrea Would you care to show a quick example of how this can be used? Or describe one. I'm trying to understand the deep end of microsolvers and what the ones you mentioned could be used for. Turbulence, Shredding, Disturbance microsolvers were covered so many times and are a lot easier to understand than "gas linear combination". I'd love to see it being used in an example file if anyone has a minute to set it up. Quote Link to comment Share on other sites More sharing options...
Andrea Posted June 1, 2019 Share Posted June 1, 2019 On 31/5/2019 at 3:57 AM, jyh126 said: hi Andrea! Thanks for your reply. I'm beginner to Houdini so don't know how to use gas linear combination, calculate etc. But I tried to use gas field wrangle and detected that if velocity is zero, collision doesn't work. Anyway I found a way to stop smoke using drag force assigned animation key in Activation. Thanks for your help again and I will use your tip someday! Sorry I had no idea you where a beginner. Glad you found the solution of your problem by yourself! 21 hours ago, char said: @Andrea Would you care to show a quick example of how this can be used? Or describe one. I'm trying to understand the deep end of microsolvers and what the ones you mentioned could be used for. Turbulence, Shredding, Disturbance microsolvers were covered so many times and are a lot easier to understand than "gas linear combination". I'd love to see it being used in an example file if anyone has a minute to set it up. They aren't really that complex. As always in Houdini you need to understand where to write or change parameters. A couple of examples with this microsolvers: example_volume_masks.hipnc (sorry for the low res, my pc tried his best) Great resources are: - The microsolvers you mentioned! If you go inside of the turbulence microsolver for example you will find other nodes. It may take a while to understand what's going on but 100% worth it. - https://ceyhankapusuz.com/2017/01/09/houdini-micro-solvers-1/ - https://nccastaff.bournemouth.ac.uk/jmacey/MastersProjects/MSc09/Claes/thesis/PeterClaesThesis.pdf which is @pclaes thesis. More advanced but full of useful informations - this forum Somewhere here there was a great topic with a lot of examples but I can't find it anymore 2 Quote Link to comment Share on other sites More sharing options...
char Posted June 3, 2019 Share Posted June 3, 2019 Great stuff, thanks for taking time to reply and present the file! Quote Link to comment Share on other sites More sharing options...
Dave Rand Posted November 4, 2020 Share Posted November 4, 2020 This example file no longer works with Houdini 18.5 Quote Link to comment Share on other sites More sharing options...
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