notintricate Posted December 19, 2015 Share Posted December 19, 2015 Hi! I created a density field from a noisy volume, then I created a velocity field from that density field. Inside DOP I advect the density field through the velocity field but my fog just goes through this velocity and disappears. What I want to achieve is continious circulation of thick smoke-like volume inside that initial shape. How can I make it circulate inside the shape with some interesting behaviour without disappearing? Any advices would be highly appreciated! advect_pig.hip Quote Link to comment Share on other sites More sharing options...
notintricate Posted December 21, 2015 Author Share Posted December 21, 2015 Hm, so many views but no replies. Is it because there is something wrong with my question? Sorry if so, i'm new here and I really did my best before posting this thread, but it seems that I can't cope with my problem alone. Would be great to hear any idea how can I move further with my issue. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
sekow Posted December 21, 2015 Share Posted December 21, 2015 (edited) your smoke dop is not complete. the most obvious part missing is some kind of border element, a collision object. you are advecting density outside of the fluid box, hence the density loss. fetch a vdb from polygons off the pig, load it into the dopnet as static object. use volume sampling and dont forget to invert the sign. you still get a bit of density loss due interpolation issues, which are better explained here: advect_pig_2.hip Edited December 21, 2015 by sekow 1 Quote Link to comment Share on other sites More sharing options...
notintricate Posted December 21, 2015 Author Share Posted December 21, 2015 Thank you for your reply, Sebastian. I naively thought that I could get it working without collision objects because I was afraid of adding one due to calculations expense. Thank you for the video as well. Seems to be helpful! Quote Link to comment Share on other sites More sharing options...
koen Posted December 21, 2015 Share Posted December 21, 2015 You could also take a look at the target driven smoke tools ( based on this paper http://www.cs.huji.ac.il/labs/cglab/projects/tdsmoke/tdsmoke.pdf). They construct forces to get smoke to form a shapen and stay inside it. If you are only sourcing inside, you should be able to get what you are after without collisions. Cheers, koen 1 Quote Link to comment Share on other sites More sharing options...
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