# All Activity

1. Past hour
2. ## SDF from density in Dops

Maybe the master himself? @Pazuzu
3. ## SDF from density in Dops

In this article: https://www.gridmarkets.com/alejandro-echeverry Alejandro describes the process of doing a pyroclastic smoke simulation. And he says: "Because we need a signed distance field to better compute the necessary fields, I did convert the density field to a SDF representation." But I can't figure out how to do that.
4. ## Best/Fast approach for car wreck look (no sim needed)?

Thanks Andrea I have a huge set of cars and the goal is to test whether it's possible to produce their wreck automatically, hence cannot sculpt manually. I am trying metaballs and so far they produce better results than just turbulence/anti aliased noise (but still sometimes, they produce intersecting pieces!). Another idea is to create deformers with metal like deformation (this is step is manual though), but then apply these deformers anomaly ! will see BTW, I've seen your car crash shot on youtube and it looks awesome
5. ## Best/Fast approach for car wreck look (no sim needed)?

Hello! Maybe you can try with manual sculpting of the damaged parts and then add on top the noise (I think I would go with worley and antialiased). You can also get extra details with the shader and painting cracks. Doing a real simulation would be cool but between geometry preparation and setting up the simulation, you risk to lose a lot of time.
6. Today
7. ## My question about UV-Flatten ...

Hi; In uv-fllaten what are pink islands? Thanks.
8. ## Ring pyro burst

Hey @Atom Attaching hip file, would be super helpful if you take a look, been struggling with this for 2 hours. For the velocity, I did a curve, polyframe N > vel. Didn't use gas curve force. I tried some stuff like: Using negative sink as velocity with no luck. Adding more dissipation affects the overall smoke but not that density artifact Checked all fields separatedly to see if some weird stuff was staying there Adding more res to both container and vel particles with no luck, also tried taking off the gasresize Deleting particle source, playing with velocty modes and stopping density Thanks! ring_density_issue.hip
9. ## Ring pyro burst

It's hard to say, without seeing the hip file. Are you deriving velocity from normals? Some times, the last point on a path can go astray. That last point of the circle, may have a normal pointing in the wrong direction, thus causing the velocity to head off in the stray direction..? If you are using a Gas Curve Force, once it reaches the end of the path, it continues in the last known direction.
10. ## Missing Point Velocity (point.v) in collision VDB

Its missing because you dont have the 'v' attribute on the incoming geometry.
11. ## Ring pyro burst

Hey @Feather thanks for the advice, did that and i think is getting closer. Now I'm trying to figure out some weird density that doesnt follow the curve after the explosion Any thoughts on what can be causing this? @Atom thanks for the good ol' wiki help, gonna check that now. Cheers!
12. ## Missing Point Velocity (point.v) in collision VDB

Trying to set up a simple VDB collision with rotating 'fan' geometry. My issue is I am missing point velocity in my VDBFromPolygons SOP. No point.v available under Surface Attributes. What is the simplest way to resolve this? collision_VDB_missingVelocity.hiplc
13. ## Making Laplacian Eigensolver plugin for Houdini

I wrote an article that is probably only of interest for the .1% It is a crash introduction to HDK, C++ and the mesh laplacian. https://mbaadsgaard.com/portfolio/laplacian-eigenvector-plugin-for-houdini/ Feedback is, of course, also welcome
14. ## popdrag - slower particle in selected radius

Hi Michal, the LYNX_force from the LYNX VFX Toolset can also do this, but more user friendly/interactively with customizable falloffs, see this video for more info. You can grab it for free here: https://github.com/LucaScheller/VFX-LYNX Cheers, Luca
15. ## How to make the pointreplicate follow the shape of the mesh

All the powerfull and magic of houdini, few line written to do what other software will do with addon or more hassle, and with less flexibility. If you are confused and intimidate but these vex lines, i could tell you that if you start learning houdini in a proper way from the base, this will look totally natural to you very quickly in fact
16. ## houdini， The effect of the internal illumination of the object

I prefer to achieve this through mantra，I made some attempts,But external objects do not show the feeling of being illuminated internally.Do you have any good suggestions for this? If there is, then I will be very grateful.
17. ## houdini， The effect of the internal illumination of the object

You seem to be everywhere, brother
18. Yesterday
19. ## Best/Fast approach for car wreck look (no sim needed)?

Hello, I need to deform a car geometry to quickly create crash like deformation (plz, see attached). Note, I don't need a full simulation, just the final shape. What is the best approach? I tried to deform some parts of the car mesh using turbulence/anti-aliased/mountain noise, but it did not look right! Another idea is to use vellum (or bullet with soft constraints) to simulate metals and hit the car by random objects, but I am hoping for something faster. Any ideas? Thanks,
20. ## Solver SOP Prev_Frame problem

Hello everyone! I'm having problem with this Solver SOP, the Prev_Frame doesn't contain the attributes I modify in the solver, like it's always the first frame. Maybe I don't understand how this work but isn't the Prev_Frame node containing the output geo from previous frame? I idea here is to check if a point velocity is above a certain threshold then start a timer on it (decreasing each frame), these points are used as a smoke emitter. The original geo is a RBD sim, at first a thought is was that but even with a test sphere it doesn't work... Please help, thanks you! panda_dust.hipnc
21. ## Copy from a random Seed

Hello, i have an issue with the copy stamp, I created a Point wrangle where I choose randomly pieces from black or red color in a loop (its a building), so i created a variable with a random in my copy stamp and i want to paste it in a seed I created in the point wrangle, in order to copy different seed of my object on point, it doesn't work at all, it's always the same copy of the same seed... Thank for any advice, cheers
22. ## popdrag - slower particle in selected radius

Hey Drughi OMG! How u guys are doing that?! works.... thank u so much!!!! But how to make it with multiple "center points". I mean more centers with slower motion of particles. I tried something in popnet/ pop vop, but unsuccesfully.... particles_issue.hip
23. ## Simulating flip from bottle

Thanks for all the answers. I still havent gotten it to not lose volume at the end. Tried different settings for couple of days now. As for volume loss, i would think that the volume loss would occur when the bottle is animated and not on the glass that is standing still? How would you set up a collider with thicker walls? if i make the model with thicker walls only for collision then i will get a problem from the flip particles colliding with that geo if they are spilled on the outside? is there a workaround for that? When you say that i should make sure the collision volume is calculated on a single frame i guess that you are talking about the glass? This one is a static object created from the shelf tools. Not sure i'm making this 100% correct but i locked the geo i use in the file and uploaded it here so you can take a look if you have time. Thanks! ek_pouring_beer_001.hiplc

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25. ## Exporting Material Diffuse Animation

Hi there, Im stuck on this problem im facing. I have created a material which basically shows the wetmap (collision history) of my flip fluid colliding with my static object. The issue I face is how to export this diffuse material as an animated image sequence in the correct uv space and unwrap of the static object model. i want to use this in maya as a shader. If anyone has any suggestions i would be thankfull forever :). Cheers.
26. ## SDF from density in Dops

I know its possible with the sop solver, but I guess it's not as fast as SDF Representation
27. ## popdrag - slower particle in selected radius

You can use length of P to control the speed. Something like this: v@v *= fit(length(v@P), radius_min, radius_max, max_drag, 1);
28. ## SDF from density in Dops

How to use the "SDF Representation" Node to convert a density volume to SDF? Or is there another way?
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