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Everything posted by bonassus

  1. rbd and softbodys

    I'm trying to understand what is possible in combining rbd and softbody simulations. Or what the workflow should be to get a fractured object to break apart like in a rigid body sim but also be a bit squishy. Like how a pumpkin might break when dropped from 2 meters off the ground. I haven't been able to get this look with fem and fracturing as the individual pieces kind of stick together on impact and don't break apart the way rbd does. Is there a solution with the multi solver? or some implementation of the grain solver that i can't think of. if someone has a solution for this i would very much appreciate it if you shared it with me. thank you. B
  2. rbd and softbodys

    Thanks for posting this. It looks like a great example of a bending/denting technique. Very interesting even if there is no explanation of how it was achieved. What I'm after is a sim that is bouncy after breaking apart. Thanks for the reply
  3. rbd and softbodys

    Sounds promising. Any chance you could provide an example? thanks!
  4. rbd and softbodys

    Thanks for the reply Chris. I'm struggling to figure out how to do this correctly. Allow me to describe explicitly what I think you are saying for your first suggestion. Run an RBD sim and cache the results. And then sim the cached geo as a granular solid? I assume that's what was meant by soft body sim (please excuse my ignorance). I have not been able to get this to work. I have attached a hip file softbodytest_grains.hiplc encase you are willing to take a look and possibly point me in the right direction. In the houdini docs in the shattering section under tips it says: http://www.sidefx.com/docs/houdini/dyno/shatter This sounds like what i want to do. but i really don't understand how to set this up. I assume this means start the solid sim on the impact frame of the rbd. would this be done without gravity in the solid sim using the velocity from the rbd sim? Also the solid embed turns the fractured pieces into on tetmesh which wont do a good job of deforming embedded geo. Is the the solution to use a loop to tetrahedralize each fractured piece and feed them separately into the sim? I'm obviously unclear about how this works and would appreciated any guidance. I have also attached my attempts at fem shattering and the rbd fem hybrid approach(neither of which work). I'm hoping you can give me some pointers to get the pieces to break apart. Thanks for any help. softbodytest_fem.hiplc softbodytest_grains.hiplc softbodytest_rbd-fem.hiplc
  5. I'm trying to simulate cloth interacting with an animated file cache. The cloth sim is pretty much from the shelf tool and the collider was set with the surface collider shelf tool. the collider is poking through the cloth. im having trouble finding which parameters to change to stop the interpenetration. i've increased the substeps by a lot but this doesn't seam to have an effect. any suggestions would be appreciated.
  6. cloth interpretations

    thanks for the reply. this sounds like it could work. I'm getting a warning on the static object node in the dopnet Warning emptyobject1: Warning: external object has no valid position at start time 2.333333333333333 I get this with or without the timeblend. I'm not sure what the time blend is doing. I've seen the timeblend work with a timeshift $F/2 but by it self connected to the cache i can't tell if its doing anything. Are you suggeting i create a ID like this?: @id = @ptnum; Is there a way to tell if there are substeps on the file cache?
  7. I've found that with finite elements(or cloth or wire) you can create multiple iteration of an geometry in a sim with the Creation Frame parameter. using floor($F/10)*10+1 see attachment I'm wondering if there is a way to do this with grain solids. I can add multiple pop source at the beginning of the sim but i would like to create a new Pop solid every 10 frames the way I can with FEM. I tried animating the impulse activate on the pop source and tried changing the activation parameter on the pop grains node. I'm guessing this is not really possible without multiple pop source nodes and point deform nodes. But maybe someone here has a solution. thanks
  8. point color on a changing mesh

    Oh right, I guess that's the only way. thanks Hernan
  9. I have an animation from a fractured finite elements sim. the resulting geometry has been smoothed with vdb and re-meshed ect. the geometry and point count is different on every frame. I'm trying to figure out a way to color parts of the geometry hopefully with the paint sop. obviously UV's are not an option. Painted or grouped points on one frame will be distributed to to different locations on the animation on another frame. A rest sop doesn't help as the geometry in constantly changing. Is there a way I can paint color on part of the animation and have it stick there. Thanks
  10. continuous stream of grain solids

    Hamp, That was just what i was looking for. Its kind of a confusing set up with the foreach sub network. Thank you!
  11. adjacent triangles not deleting

    Thank you acey195 i appropriate the help.
  12. Can anyone tell me why this happens? I divided some quads from a grid. In a foreach loop i grouped prims with 3 points: if(npoints(0)==3){ f@group_delete = @ptnum; } but it only adds half of the triangles to the group. If i do npoints()==4 no prims are added to the group. If i do unique points before the loop only some of the quads are added. I suspected that this has to do with vertex numbers v.s. point numbers. so i tried primvertexcount() but got the same result. how can i remove all triangles from this geo? thanks b
  13. qLib Plugin Installation?

    Thank you f1480187 your exaple worked for me. this was confusing for me. in fact the read me file has this: QLIB=<<path to qLib install>> QOTL=$QLIB/otls HOUDINI_OTLSCAN_PATH = $QOTL/base:$QOTL/future:$QOTL/experimental:@/otls HOUDINI_GALLERY_PATH = $QLIB/gallery:@/gallery HOUDINI_TOOLBAR_PATH = $QLIB/toolbar:@/toolbar HOUDINI_SCRIPT_PATH = $QLIB/scripts:@/scripts I did not know how to interpret this into what you provided. what is &; Is this hscript? thanks.
  14. two objects in a granular solid sim

    I'm trying to set up two pig heads in a grain sim that collide together. an extension of the grainular solid example in Jeff Lait's h15 grains masterclass. in stead of one pig head i want to wire in two. I've set up two pig heads (skipping the bone group part for now) see attached file. Jeff shows how to override the P and v with from an animated version of the geo with a wragle. I've set the dop net up the same way with two sources. however for some reason one of the P values apparently collapses to 0. if i switch the merge order it switches which source goes to 0. see attached file. I'm obviously missing something here. help would be appreciated. twosolidpigs.hiplc
  15. I'm trying to arrange (or add) points on a line so that the distance between them decreases based on a ramp. I have a ramp controlling Cd on the line using: @ptnum/(@numpt -1) I tried using a scatter node and generating the points based on Density Attribute Cd. But this results in some randomness in the decreasing distance. I thought I could use the resample node's distance attribute. but i haven't figured it out. I could one could shed some light here I would appreciate. Thanks B
  16. Hey thanks! that works well. Okay now I have a random question that you may want to answer. why do I get a different result if i combine the code from the two wragles in to one? It seems like the order of operation should be the same. No? Thanks Again.
  17. I'm trying to control the normal of a single point. I want to use normals to visualize vectors that i will convert to velocity later. I've reduced my experiment to a single point to hopefully simplify things. I'm trying to make the normal point in a truly random direction for each frame. I tried this: float x = fit01(rand(ch("seed1")),-1,1); float y = fit01(rand(ch("seed2")),-1,1); float z = fit01(rand(ch("seed3")),-1,1); @N = set(x,y,z); which gave me a random direction with in a disk. If i substitute @N for @v and feed this into a popnet that uses inherited vel i get particles in a plane. see attached image. If I control each component of the vector leaving two at 0 and setting the third between -1 and 1 i can point the normal in any direction. I can't figure out how to get houdini to randomly set the normals direction in all directions. Help appreciated.
  18. random normal direction

    Oh okay. the rand function run once for each component in the vector() I assumed it was just casting the resulting value. thank you noobini. F1, thanks for the clarification and the two examples that also do the same thing.
  19. random normal direction

    ikoon, thanks for the reply. I'm not sure what you mean.
  20. random normal direction

    James, thanks again for the vex solution. v@v = (vector(rand(ch("seed1")))-{0.5,0.5,0.5})*2; allow me to attempt an explanation. The rand function returns a value between 0 and 1. casting it as a vector creates a 3 float vector with 3 identical values. subtracting the 0.5 vector makes some values negative and then multiplying by 2 normalizes the values. shouldn't this create a vector with three identical values? why is this equivalent to Noobini's offset solution?
  21. random normal direction

    Vusta, thank you for the demonstration. I see you can get a roughly even distribution of directions by offsetting the sin cos functions. weird.
  22. random normal direction

    thank you! that works. I wish i understood why that works.
  23. I'm trying, with out success to create an Id map to use in substance painter. something like the quixel colors plugin. I assigned two principled shaders, with different base colors with a material sop at geometry level based on primitive groups (see Attached image). I set up a baketexture rop to export a basecolor image plane, see attached image. The exported image is white. I want uv rendering of the colors in the textures. There is something i don't understand called a uvlense shader. do I need to use this? I didn't add any lights to the scene I don't think i need them. I got this warning: A head-light was automatically added to the scene. If the soho_autoheadlight parameter cannot be found in the Objects tab, add the rendering property to control this behaviour. I would appreciate if someone would point me in the right direction. Thanks
  24. Thank you for your reply. I found that the games baker from the game develpment toolset did what i wanted it to do. An id map is just a colorized uv map. Substance can select using the colors that are assigned to the uv map. thanks again
  25. I'm wondering if someone can help me out. I have a bunch of line primitives and i want use a carve sop to make them appear to grow. But I would like to stagger the effect so that prim 0 starts to animate with the carve and when its 50% prim 1 starts to animate and so on. I can't think of how to do it. I put them in a foreach loop but still not sure how to stagger the effect. help would be appreciated.