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fieryspoon

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About fieryspoon

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    Ben
  1. Vorticity for particles

    Can you do a VDB from Particles and turn the particle velocity 'v' into a volume grid velocity 'vel'?
  2. packed point number on unpacked geo

    The foreach would work for me. Thanks very much! :-) You're saying that if I want to emit packed objects, the best way would be to: unpack it before adding it add the ID repack it add it to the sim ? I feel like the unpack sop should have the option of adding the original packed point number as an attribute.
  3. packed point number on unpacked geo

    Here's an example of what I mean. packedpoints.hip
  4. packed point number on unpacked geo

    Hi, thanks! I don't have a 1 to 1 correspondence of packed points to unpacked name attributes. I'm emitting the rock geo over time and re-using some of the rock models sometimes, and I think that due to a memory optimization, it's storing the points that refer to the same geometry under the same 'name' attribute when it unpacks it. I'll put together an example of what I mean.
  5. packed point number on unpacked geo

    Unpacking it adds a 'piece*' primitive attribute, but the highest piece number is 312, but I have 650 points in the packed geometry, so I'm not sure how to build an association with that. I have 312 unique rock types in the sim, but I need to isolate them per rock, not per rock type.
  6. I have a bunch of rocks that I've got in a bullet simulation, and now I need to unpack the geometry and modify them based on some data on the packed points. I want to get the packed point number after unpacking it. Or, basically just figure out some way to associate the packed geo points with the unpacked geo. How can I do that? Thanks, Ben
  7. Using DCM Holdouts with Volumes

    I'm also interested in this. Did you ever put together a worst case geometry file? :-)
  8. Hey Solitude -- do you have an example of how this is put together?
  9. object thickness

    What's the best way to get the thickness of an object? What I'm doing right now is: 1) Convert the object to VDB, making an SDF. 2) Analyze the gradient of the SDF to get the direction to the surface 3) Scatter a bunch of points in the volume 4) Transfer the SDF and gradient values on to the points. 5) Move the points along the gradient * SDF, to get all the points to be on the surface 6) using a local point cloud to transfer the minimum SDF values to the local area 7) transferring those values on to the original polygon points This seems extremely gross and unreliable, especially since it's using point clouds to do the attribute transfer. It's unreliable because I can't rely on a specific point density or whatever. In general, I'd like to have a more exact method of figuring this out. Preferably without rays, too, but that might be another option. I also figured that SSS must have a way of determining object thickness, right? Thanks!
  10. sop solver points changing

    Hi -- could you post your hip file? It's a little hard to figure out what's going on without seeing it directly :-)
  11. I used a SOP solver to transfer the data over from the SOP context and added it between the bullet solver and the pop force. I think the deal is that within dynamics contexts, the dynamics take over control of every attribute. So you need to explicitly pull in the attributes you want, if DOPs isn't controlling them in another way. I normally do the transfer with a VOP SOP, but in this example I used attrib copy, since it's a little clearer for examples :-) You don't want to just overwrite every attribute wholesale, because then things like P or v or whatever else would also be overwritten and you wouldn't get any motion. packedattrib_sopsolver_BA.hipnc
  12. Animated packed primitives in H13 Bullet

    Whoops, I didn't attach the file. packed_prim_xform.hipnc
  13. Hi -- I'm trying to figure out a way to get animated/deforming geometry working for packed primitives in dops. I really like working in VOPs and SOPs, so the packed primitive workflow is really appealing to me, but I can't seem to figure out how to get animated/deforming colliders. I have gotten my packed primitive to animate and match the animation in SOPs, and activate based on an attribute This is my best attempt so far. Inside the dop network, there is a red switch node. You can switch between the packed and unpacked primitives, for reference. The unpacked primitive never gets released to becoming dynamic, but maybe it's useful. Inside the green sop solver in the DOP network is another red switch node. The first input here works great after the packed primitive becomes dynamic, but doesn't collide properly/at all until then. The second input works while it's tied to the animation, but gets all squirrely and weird afterward. It's almost like the pivot point is totally off, or.. I don't know. More confusing than that is that the guide geometry is clearly not what the bullet solver is colliding with, since the guide geometry is in the right place. Could someone take a look and see if there's a better way to do this? All I want is for my packed primitive to be tied to some SOP animation for a while and then become active in the scene. Also, as an aside, do DOP groups work correctly and reliably in a multi-solver? I know it's a dumb question, but I have had a pretty hard time isolating which geometry my solvers are running on so far. Thank you so much to anyone who can help :-)
  14. rebuilding a fractured object

    Was anyone able to figure out how to match the rotation and turn off collisions for those pieces?
  15. Isolate solvers to certain groups in DOPs

    Hrm, filling in the group name to solvers if the first input is empty seems to work erratically. It works now for the sop solver after recooking it a few times, but the fan_force says it's an invalid group. I'm pretty new to DOPs, but maybe someone could explain what the intended workflow is for building solvers that operate on only parts of the simulation within a framework that is simulating all of those individual pieces together?
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