juvilian Posted December 18, 2019 Share Posted December 18, 2019 * Posted the same question in Houdini forum. But no reply until now. So reposting here I want to create an effect where a Flower is getting hit by drops of rain water. The water drops sticks on the flower and slowly drips down. I need to create the wet map. As well as, the flower should react (bend or disturbed) when the drops fall on it. I am fairly new to houdini. If someone can suggest me a path to achieve this effect, it will be very helpful for my R&D. Please suggest me a brief process from where i can start developing. I am hoping to learn a lot from this project. HERE are SOME REFERENCES Quote Link to comment Share on other sites More sharing options...
toadstorm Posted December 18, 2019 Share Posted December 18, 2019 I documented a process like this on a short animation I made a couple years ago: When I did this I was stuck with FEM because Vellum didn't yet exist, but you could do this waaaaay faster using Vellum and some Vellum-friendly force attributes... you'd just have to translate a little bit from the FEM solver attributes I was using to generate force. The short answer is that I just randomly applied forces to areas of the leaves/petals until the rhythm of the impacts looked believable, and then I isolated those impacted positions in the simulation and used them to generate raindrops after the fact. The raindrop particles were POPs that I slid down the petals using the "gradient descent" algorithm (described in the following blog post), and then randomly released after a time. It was easier to do it this way and get the timing right than to actually try to collide the leaves with falling raindrop particles. This is a long post, scroll about halfway down and you'll start seeing how the impacts were done: https://www.toadstorm.com/blog/?p=557 There's a HIP file you can download linked at the beginning of the first post in the series: https://www.toadstorm.com/blog/?p=534 4 Quote Link to comment Share on other sites More sharing options...
juvilian Posted December 18, 2019 Author Share Posted December 18, 2019 6 minutes ago, toadstorm said: I documented a process like this on a short animation I made a couple years ago: When I did this I was stuck with FEM because Vellum didn't yet exist, but you could do this waaaaay faster using Vellum and some Vellum-friendly force attributes... you'd just have to translate a little bit from the FEM solver attributes I was using to generate force. The short answer is that I just randomly applied forces to areas of the leaves/petals until the rhythm of the impacts looked believable, and then I isolated those impacted positions in the simulation and used them to generate raindrops after the fact. The raindrop particles were POPs that I slid down the petals using the "gradient descent" algorithm (described in the following blog post), and then randomly released after a time. It was easier to do it this way and get the timing right than to actually try to collide the leaves with falling raindrop particles. This is a long post, scroll about halfway down and you'll start seeing how the impacts were done: https://www.toadstorm.com/blog/?p=557 There's a HIP file you can download linked at the beginning of the first post in the series: https://www.toadstorm.com/blog/?p=534 Thank you so much... I am gonna go through the process and try to learn as much as possible from this. This is an incredibly awesome work... 1 Quote Link to comment Share on other sites More sharing options...
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