dangerweenie Posted June 20, 2011 Share Posted June 20, 2011 Hi there, I'm running a simulation in which a long branch collides with an object during a storm. Everything simulates fine (using an L-System -> polyWire -> voronoi_points -> voronoi_fracture -> RBD Glue), however I'd like to get a bit of bend or deformation along the length of the branch as it snaps upon impact. Does anyone have any advice? Thanks! Matt Quote Link to comment Share on other sites More sharing options...
Netvudu Posted June 20, 2011 Share Posted June 20, 2011 Are you sure you want to use dynamics for that? From your description it sounds like something I would like to hand animated with a lattice or something... Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted June 20, 2011 Author Share Posted June 20, 2011 Are you sure you want to use dynamics for that? From your description it sounds like something I would like to hand animated with a lattice or something... Yes, I'd like to try and do it with dynamics, as we might have to change the angle and speed and shape and impact of the breaking object after review. Keyframing by hand was my first solution, though, and it's what I'm doing at the moment - I'd really like to try and figure out how to bend a fracturing object, though, for the sake of learning. Quote Link to comment Share on other sites More sharing options...
Adam Ferestad Posted June 20, 2011 Share Posted June 20, 2011 I would look at deforming the system using a bend on the points for the branch before I put it through the simulation. If you time it right, it should all come together to give the basic effect you are looking for. The other option, and I haven't gotten into doing breaking geometry yet so I'm not sure if it is there, would be to affect the elasticity of the branch. If it processes right, that should allow it to bend some before finally snapping off. Again, I have no idea if the option is there or how it will process, but I would imagine it is somewhere in the RDB Glue settings. Quote Link to comment Share on other sites More sharing options...
Netvudu Posted June 20, 2011 Share Posted June 20, 2011 (edited) I´m not sure what Adam´s suggesting will work at all. His first option sounds as non-procedural as the previous options. Regarding his second suggestion, I don´t think the Glue Object has an elasticity setting at all. At least, I can´t find it. If you wanna go the dynamics way, you owe it to yourself to take a look at the SOP Solver which would be a way to add deformations to an object, and activate those deformations with dynamics. That would allow you to go the procedural way and still use geometry deformers. Edited June 20, 2011 by Netvudu Quote Link to comment Share on other sites More sharing options...
ikarus Posted June 21, 2011 Share Posted June 21, 2011 id build a wire sim of the branch and sim that up until the point it breaks then change it to a rbd/breakable object and break it that way, there's several example files floating around that do similar things Quote Link to comment Share on other sites More sharing options...
michael Posted June 21, 2011 Share Posted June 21, 2011 to expand on what ikarus suggests... build a set of wires (one for each branch/subBranch), wire solver, then animate the gluetoanimation attribute lots of options here. Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted June 21, 2011 Author Share Posted June 21, 2011 Thanks for the quick replies, everyone. So yes, the bend deformer is great, but it's not really the procedural result I am going for. Doing it all dynamically isn't the most practical for production, but I find the challenge helps develop my understanding of Houdini, which I am still new to. The glue settings have been very useful, but only insofar as they are letting me control which parts of the branch break, based on impact force. I haven't seen any elasticity attribute. The wire solution sounds interesting - I'm coming from Maya, and while I haven't used wires in Houdini at all, I imagine that the tools offer at least somewhat similar functionality. At the moment, the whole branch is only one L System going into a polyWire -> RBD. What you guys just suggested about doing it with a SOP -> DOP seems to be the consensus among other Houdini artists I've asked as well. I haven't found any example files illustrating this workflow, but I think I get it. The question is, do I run the SOP to achieve the bend, and then fracture the object, or do I run the DOP fracture, and then apply the SOP to those sub-pieces? It seems pretty obvious that the former would be best, however I'm wondering if by doing that I am losing the force and velocity that the RBD simulation has been building up to the point of impact. I'm not sure if "inherit velocity" is going to help. Would it help to run the sim as RBD up to a frame or two before impact, then set that as the initial state for the geometry after it gets handed off from SOP to DOP? Again, thanks for the advice! Any more ideas are appreciated. I'll be sure to follow up once I get a good result. to expand on what ikarus suggests... build a set of wires (one for each branch/subBranch), wire solver, then animate the gluetoanimation attribute lots of options here. Quote Link to comment Share on other sites More sharing options...
Netvudu Posted June 21, 2011 Share Posted June 21, 2011 Apparently you didn´t read properly where I wrote SOP Solver Dynamics-driven SOP deformation. You don´t have to loose your velocity at all, AFAIK. This being said, I love ikarus suggestion. In fact, I think it is way better than mine. I would try that as opposed to the SOP Solver solution. Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted June 23, 2011 Author Share Posted June 23, 2011 Apparently you didn´t read properly where I wrote SOP Solver Dynamics-driven SOP deformation. You don´t have to loose your velocity at all, AFAIK. Ha, sorry. Like I said I'm pretty new with this (coming from a few years of Maya), but I'm getting the hang of the whole network anatomy, etc. I know what you meant now. This being said, I love ikarus suggestion. In fact, I think it is way better than mine. I would try that as opposed to the SOP Solver solution. Even missing you and Ikarus' advice, I kind of found my way (eventually) to trying to get the results with the SOP solver. The main issue I'm having now is how to copy, move, import and generally hook everything up. I've been trying to work with the "Multiple Solver" node (SOP solver, POP solver, Cloth Solver, etc) + (RBD Solver) for most of the day. Not really getting anywhere though. It seems like I need to find a way to get the point data from the RBD sim into the SOP solver. The included "simple multiple solver" .hip file included in the example scripts is quite promising and taught me alot, but it only changes the color of the points - doesn't use any fetch or DOP reference at all. I've been trying to cannibalize it into something better but everything I've tried is a dead end. If you have any good examples of two solvers working together on one object (ideally a RBD solver + something that deforms the object at the shape level), I'd be quite grateful. Thanks again for the feedback! Best, Matt Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted June 23, 2011 Author Share Posted June 23, 2011 um. can someone with admin delete the twelve billion replies i accidentally posted earlier? kthx. Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted June 24, 2011 Author Share Posted June 24, 2011 Thanks for the advice guys, I found an example scene that demonstrates what you were suggesting - the proper way to use a SOP solver combined with a RBD solver -> multiple solver in a DOP network. It's called "dentingwithpops.hip", if anyone newcomers out there encounter a similar question. Quote Link to comment Share on other sites More sharing options...
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