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Andrea last won the day on August 14

Andrea had the most liked content!

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About Andrea

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  • Name
    Andrea Sbabo
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    Venice, Italy

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  1. Vegetation using bullet

    Probably here I could have used wires for simulating the branches since they are essentially splines. But in the past I've done some trees simulation with them and I spent most of the time making little changes in the wires parameters for avoid them to get stuck in walls or each other. At the same time I have to say they were really good and easy to use in the scenes were the trees had not much movement. Anyway some people made some amazing plant simulations in Houdini with wires so maybe there are some nice tricks that can be used. Thanks for the tip. If I have the time before moving (&co) I'd like to try change the rotational stiffness and see the difference
  2. Vegetation using bullet

    Yes I can. I was also going to write a short explanation/reminder on my website, but I need to clean it up a bit
  3. Vegetation using bullet

    Thank you Jesper!
  4. Vegetation using bullet

    Hi! Here is something I've been working for a few time on and off. I was searching for something that I could use for plants that are colliding near the camera. So I ended up using the bullet solver with packed geometry. I'm not sure if it's the right way to go for this kind of things but at least I learned a lot about the constraints. Thinking afterwards I probably should have used a few more substeps but I hope you can enjoy it anyway! Suggestions for improvements are welcome
  5. White water question

    If you cached the flip simulation immediately after the dop import and before the fluidcompress (so you have particles + volumes) it should work. Looking at the second video looks like you are missing the velocities from flip
  6. Pop Collision Ignore + Grain Solver

    Thank you for the explanation @3dome! With "it feels wrong" do you guys mean you get two different results? I just tested it again I got the same exact behaviour. But maybe that's because here we still have Houdini version 16
  7. Pop Collision Ignore + Grain Solver

    Great topic and solution! Basically the pbd_group you set to zero is the group that is used inside the POPgrains for the collisions? I've noticed that if in Alvaro setup I disable the "Gas collision detect" the box still collide and the sphere is not. I'm not sure if it happens because they are obeying to the popcollisionignore or something else it's going on.
  8. RBD Glue Constraint Mysteries....

    Here is your scene with some stuff added. Primitives switch to red when they enter in the group "isbroken" which means that the popforce affects them. The volume velocities affect just the primitives that aren't in the group. The group is created in the sopnet inside the Dop network. Here the wrangle checks if the constraints are broken or not every frame. If the constraint is broken then the primitive is in the group "isbroken". The result of this is loaded in DOP through the SOP solver rbd_constraints_test00.hip
  9. Simulation inside a loop

    Thank you again, it worked perfectly!
  10. Simulation inside a loop

    Thank you, I completely forgot about them. Tomorrow I'll try
  11. Hi, I have multiple RBD object that are simulated. I would like to cache them separately for the entire timeline since each object doesn't affect the others. I've been thinking to put everything inside a foreach loop but the issue is where should I put the filecache. If I put it outside the foreach calculates every object frame by frame and not object by object as I would. If I put the filecache inside the loop I don't know how to run it for every iteration. Any suggestions on how can I do that?
  12. How to break pieces in animated alembic mesh

    Yes you are right. I've used only P because there weren't any other informations in the geometry. If there is rotation I think you can still use this method, just in the SOP wrangle you need also to read and copy other attributes like "packedfulltransform" to "transform". As far as I remember if there is deformation I've always used hard constraints. One really cool trick is using uv coordinates for fix the constraint to the deforming object that has a different point count every frame. Testing by ourselves is the best way to learn
  13. Bullet constraints network questions

    2) Glue, hard, spring and cone are different type of constraints with different behaviours and attributes that you can use for get the desired result. For example spring constraints can stretch, glue constraints can't. "All,position, rotation" has nothing to do with this but specifies if the constraints are allowed to rotate or change the relative position between the extremities. In the example files of Houdini there are some great scenes where you can easily see the difference between them. 1) Said this... It's true that if you don't allow the change of rotation/position (constraint_type->all) on hard constraints they are almost as unbreakable glue constraints. But keep in mind that glue constraints can just be broken or not. With hard constraints you can do much more. For example with hard constraints you can specify the exact direction that they are allowed to move, how much they have to move or rotate before breaking and so on.
  14. How to break pieces in animated alembic mesh

    Hi, sorry for the late reply, I was busy. If you haven't fixed it yet here is how: glue_to_alembic_mod.hip The problem in the scene was that in the "kinematic" RBD packed object you had the "create deforming object". You see in the viewport that the kinematic is moving but in reality it's deforming and not moving. As far as I know, you need the packed object to move for update the contraints and everything attached to them. So I've put "Create animated static object". Now the geometry it's not moving because the animation happened before the voronoi fracture. So that's why I've freezed the geometry in the first frame and moved it again using the wrangle in SOP. I'm not 100% sure why is this an issue since @P it's moving anyway, but it fixed it.
  15. How to break pieces in animated alembic mesh

    I don't think it should be a problem if you convert it the alembic to regular Houdini geometry. Try give a look at this: