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bonassus

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Everything posted by bonassus

  1. I'm watching Steve Knipping's Applied Houdini-Rigids III. He does a point snap align thing that I don't understand. see attached vid. He calls it a magnet snap which I assume is a Maya term. Can someone explain how he does this? Thanks magnet_snapping.mp4
  2. magnet point snap align

    Awesome, Thank you. I didn't know about part where you hover over the second point. Thanks for taking the time to demonstrate this.
  3. magnet point snap align

    Thanks for the reply woodenduck. No, the geo in the video i posted is a test with a line sop. It's not packed. It's just two points and a line prim and yet point snapping does nothing...
  4. magnet point snap align

    I can make point snapping work in some cases but not in this one. see attached video. My original question is how to do the point align to axis snap but i can make these points snap at all. Why does it not work? thanks snapping.mp4
  5. magnet point snap align

    Thanks. I did notice that. Its not working for me. I select the bottom point enable the transform tool turn on point snapping. no snapping happening. not sure why. seams like it would work.
  6. Houdini 17 Wishlist

    I have an obvious suggestion for chops. Dot syntax in the attribute Scope parameter field on the Channel node. This works P(1) but not this P.y
  7. colon in path

    I have an object merge inside a sop solver that is inside an rbd sim. The object merge is pointing to the Geometry in the rbd object from the sim. with: ../..:rbdobject/Geometry Why does this work with the colon? why isn't it another forward slash. ../../rbdobject/Geometry I understand that its pointing at the rbd object which is different than the rbdpackedobject node. What does the : signify? thanks
  8. Thanks for posting this. It is a very helpful example for beginners like myself. I'm wondering if there is a way to use cached geometry as the source for a setup like this? I like the motion of an rbd sim but would love to add some squishy/springy motion to the fractured parts. So that it doesn't look like concrete. I have tried running the sim through an fem sim very similar to this but I can't get it to work on the deforming mesh. I wonder if you have any ides for me. Thanks agian
  9. 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
  10. 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
  11. rbd and softbodys

    Sounds promising. Any chance you could provide an example? thanks!
  12. 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
  13. 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.
  14. 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 $F/2 but by it self connected to the cache i can't tell if its doing anything. Are you suggeting i create a ID like this?: @id = @ptnum; Is there a way to tell if there are substeps on the file cache?
  15. I've found that with finite elements(or cloth or wire) you can create multiple iteration of an geometry in a sim with the Creation Frame parameter. using floor($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
  16. point color on a changing mesh

    Oh right, I guess that's the only way. thanks Hernan
  17. 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
  18. 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!
  19. adjacent triangles not deleting

    Thank you acey195 i appropriate the help.
  20. 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
  21. 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.
  22. 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
  23. 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
  24. 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.
  25. 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.
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