ashu_tosh_m 3 Posted April 2, 2020 I was trying to expand the some smoke simulation using divergence field. the divergence field create a big hole in the smoke simulation. any idea why is this happening Test Smoke.hiplc Share this post Link to post Share on other sites
Atom 1,234 Posted April 2, 2020 I think divergence needs to be negative. Try changing your keyframe value from 20 to -20. Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 6 minutes ago, Atom said: I think divergence needs to be negative. Try changing your keyframe value from 20 to -20. its still creating hole after changing value to -ive Share this post Link to post Share on other sites
Atom 1,234 Posted April 2, 2020 (edited) Hmm... That's Od. (rewind to clear old cache..?) Here is negative divergence using your scene. I made the attraction point, bigger and visualized it. Edited April 2, 2020 by Atom Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 6 minutes ago, Atom said: Hmm... That's Od. Here is negative divergence using your scene. I made the attraction point, bigger and visualized it. can u share this hip file? Share this post Link to post Share on other sites
Atom 1,234 Posted April 2, 2020 Sure, here you go. ap_test_smoke_divergence_040220.hiplc Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 44 minutes ago, Atom said: I think divergence needs to be negative. Try changing your keyframe value from 20 to -20. Ops i made the value from 20 to -20 not from 0 to -20 :-| thats why i was creating a hole ! Thank You sooo much :-) Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 (edited) 14 minutes ago, Atom said: Sure, here you go. ap_test_smoke_divergence_040220.hiplc Hey its working but i want to expand the smoke.. its looking like the divergence field is attracting the smoke .. how to expand the smoke.. I want to make something like this.... look how the smoke got expanded in this video.. Edited April 2, 2020 by ashu_tosh_m Share this post Link to post Share on other sites
Atom 1,234 Posted April 2, 2020 A lot of that look is determined by collision objects. Add a ground plane and make your velocity point down. You can check out my fuel based rocket launch thread here. Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 1 minute ago, Atom said: A lot of that look is determined by collision objects. Add a ground plane and make your velocity point down. You can check out my fuel based rocket launch thread here. BTW I'm not making rocket launch smoke..... i want to learn how that guy has expanded the smoke. Share this post Link to post Share on other sites
toadstorm 307 Posted April 2, 2020 (edited) If you want to make smoke expand, source a scalar field with positive values like you'd source any other field (density, etc), and set the destination field to "divergence". If you're getting holes inside, consider adding more density into the area that you're expanding. Edited April 2, 2020 by toadstorm Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 1 minute ago, toadstorm said: If you want to make smoke expand, source a scalar field with positive values like you'd source any other field (density, etc), and set the destination field to "divergence". yes i have done that... its creating hole u can check the screenshot .. or hip file that i had shared.. Share this post Link to post Share on other sites
toadstorm 307 Posted April 2, 2020 Looks like you're losing density because your divergence scale is enormous, and it's causing the velocities to be too high relative to the time increment. If you increase your max substeps a bit, you should get more accurate results. Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 Just now, toadstorm said: Looks like you're losing density because your divergence scale is enormous, and it's causing the velocities to be too high relative to the time increment. If you increase your max substeps a bit, you should get more accurate results. u have increased the substep? may u share this hip file.? it will be easy to understand.. bcoz im noob in Pyro Share this post Link to post Share on other sites
toadstorm 307 Posted April 2, 2020 It's the same exact file you uploaded. All I did was increase the maximum substeps on the Pyro solver to 4, under the Advanced tab. Share this post Link to post Share on other sites
ashu_tosh_m 3 Posted April 2, 2020 1 minute ago, toadstorm said: It's the same exact file you uploaded. All I did was increase the maximum substeps on the Pyro solver to 4, under the Advanced tab. okay thank you..... let me try Share this post Link to post Share on other sites
Atom 1,234 Posted April 2, 2020 (edited) You can set the Operation of the divergence field to Subtract and the smoke will move away from the divergence field, instead of being drawn in. Upres on right. Animating the scale of the volume might not be the best approach. All that does is increase or decrease the value in the area of the divergence field. To expang and area, you might try want to animate the scale of the divergence field shape at the SOP level and leave the DOP scale set to a constant. That way, when you expand the size from zero and up, the field size area of effect will grow, not the strength. ap_UPRES_smoke_divergence_040220.hiplc Edited April 2, 2020 by Atom 1 Share this post Link to post Share on other sites