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Everything posted by violalyu

  1. Thank you so much! Somehow I cannot hit thank you on your entry...lol
  2. Falling Dust - Characteristic

    Still testing on this lol
  3. Falling Dust - Characteristic

    Hi Houdini friends! I've been trying to do a sim for falling dust, the kind of look I want to get is similar to this: The shape of the leading edge of the falling dust is "spiky" and has the grainy details. I kind of "cheated" by giving it a high disturbance and warp the velocity field so that all vel.y will be going down and scaled down vel.x and z, but when there's interaction with collision geo this will not work since the velocity field is manipulated, and it gives this "sliding" behavior along the collision geo. Attached is an example file that shows this issue. Has anyone done similar sim before or have any advice on how to get this kind of characteristic in the sim? Thank you soooo much in advance! Much appreciated! fallingDust_test.hipnc
  4. Pyro smoke localised drag

    Hi Agelos, you could try gas damp, you can check out the parameters and play with them, should be able to get that effect:)
  5. Velocity Field issue with smoke clustering

    @Atom Hi Atomic, thanks for the reply! However, it seems the density and temperature field already have a suffix with cluster number... their name is density_1, density_2...etc, and it's still doing that though:( @fencer Hi Paul, thanks for the reply! That works for me now, and learnt some new thing today lol, thank you so much!
  6. Hi Houdini friends! I'm having some issues with getting velocity field to work with volume clustering... I made a simple example file (please see attached) to show this issue, and in my actual scene I've also tested with force and deforming static objects as collision, and both seem to work, but not with velocity field, and this velocity field will work if i turn off instancing on smoke object and fluid source with the same exact set up. Does anyone else had this before or have any idea how this is caused or workarounds? Thank you sooooo much in advance! Best, Viola cluster_velFieldIssue.hipnc
  7. Hi @pak thanks for the update! Good to know
  8. Hi @pak, I didn't have the error message, but it is basically the same for me, it might be Houdini version difference? I'm using Houdini16.0.633, something might changed from 15.5 to 16? Also it seems you need the group attribute on the points for some later operation? Maybe there are other ways to directly achieve that, like instead of using group name as the "marker", there might be other attributes that could be used?
  9. @pak yes sorry I wasn't reading the title carefully! I went from @jon3de 's file and added a (very roundabout) way to get the group name as an attribute on the newly created centroid points, I'm sure there are better ways, but I'll just post it here in case this could be of any inspiration :-) pointsOnPrimitiveGroups_viola.hipnc
  10. One way I've used before is scale it to 0 on a per primitive basis and then fuse all the points, so that you get the center point of each one. Hope it helps :-)
  11. Guiide geometry for Shattered pieces incorrect

    Hi Zac, I tried in your file, by tightening the collision padding (in this case i changed it from 0.02 to 0), that will make a better representation of the smaller pieces. Hope it helps.
  12. Retime slow motion points

    using match by id probably?
  13. Hey Houdini friends! Does anyone know if the straight corner style wiring display of network is deprecated in Houdini 16? I tried SHIFT+S and there's only rounded and "straight"... Thank you so much!!!
  14. Hi everyone! I was trying to see how OSL works in houdini, and there's pxrOSL and ris_oslShader in the RIS NET, and this is what I did for testing purpose, it doesn't seems to work. I did bind export in the ris_oslShader and exported a const color red, referenced it in PxrOSL and wired the result into pxrDisney, but the base color didn't change. Has anyone tried these nodes yet? Please advice, thanks a lot!!!
  15. Offsetting cached animation inside DOPs

    Hi @orinfitchett, I made a simple test file where it is just particles, and it is kind of a post sim thing so it will not have actual dynamics, if you are using a multi solver setup where you have bullet and pop solver, and you want the actual sim to be handed off at a specific frame from animation to actual rbd sim, you might have to do this inside a sop solver in dop. However if the explosion will not react to other geos, this should work just fine:) Hope it helps! offsetCache_viola.hipnc
  16. Spin force for RBD objects

    Hi Houdini friends, Sorry to bother you three times in a day... I'm still having issues with the simulation of leaves on the ground. I can't use POP for simulation because these leaves are in foreground and they'll hit the ground and stay eventually. However it seems wrangle torque or angular velocity on the packed points won't work, these leaves are not spinning around their own origin. Is there any way to fix this? I have the files attached that may better explain. Thanks a lot!!!
  17. export point P data

    Hi Martin, Probably run a sop solver where you could give it a vector array and every frame push the P in the array?
  18. Reducing Stretch and Bounce in Grain Ropes

    Hi Dylan, From last time I did some stretchy thing with pop grain, since it is pop I tried "taming" it using pop drag, and it helped a little bit, also you can write in a pop wrangle where you force the velocity to go low once it reach some high value, hope this helps!
  19. Deal with substeps and gaslinearcombination

    Sorry my bad, if it's 1.02 per second you could probably do pow(1.02, @TimeInc), if it's 1.02 per frame then probably pow(1.02, 1.0/substep) :-)
  20. Deal with substeps and gaslinearcombination

    Hi Tom, From my understanding I think @TimeInc is the length of time for one substep, however rethinking this problem, since it is a multiplier, and you want say 1.02 per second, so probably something like pow(1.02, 1.0/substep)? so that they match 1.02 per second upon multiplication?
  21. Deal with substeps and gaslinearcombination

    Hi Tom, Probably consider using @TimeInc something like that?
  22. Trail SOP help

    Hi Tim, I think the trail is actually doing the right thing, since your point number is not changing only the positions, the points go suddenly from one end to another, and that is causing the velocity and the added geometry to suddenly get large. I attached a cheat way where you just delete those long edges caused by this... and after this you could probably keep track of the point number that belongs to the deleted primitive, do a point cloud look up for these points to their neighbors and use average v as velocity and compute the other end of the line based on this velocity and add that line? Sorry I could not think of a direct way to fix it right before the trail so that you don't need to do all these post process... Hope it helped! broken_trails_cheatVL.hipnc
  23. Hi Fyre, I did a really rough test as posted, i could be getting you wrong, so maybe you could explain in more details? Thanks! pc_connectTest_viola.hipnc
  24. Hi Craig, Maybe check on "use object transform" on your rbd object in you dop?
  25. Hi Jason, If this is on SOP level, you can use a sop solver and compare it with it self from last frame, something like if(point(1, "active", @ptnum)) { i@active = 1;} where you have the first input as itself and the second input as prev frame. However, if you are doing the vop that you are doing inside dop solver it should keep your comparison, imho. Hope it helps!