noumiere Posted October 24, 2018 Share Posted October 24, 2018 Hi there, I am currently doing RnD on an effect that I am trying to achieve that involves cutting a long strip of geo (think of it as a strip of plastic) using another object (blade) I have approached this head-on while learning Houdini and I have learned tremendously just by making mistakes and troubleshooting on the go - I have learned so much and this is the best part of learning Houdini in my opinion. At the moment I have tweaked a basic Houdini wire solver and used a Wire Capture to drive geo using that wire deformation. My question : I would like to know how I can go about cutting this Geo driven by the Wire using another object? The hip file with my tests is attached. Some tips I have found so far is that 1) You cannot fracture a wire instead, use a ConvertLine node (This warps my geo) I would greatly appreciate any help and pointers! Thanks wire_constraint_example_v02.hipnc Quote Link to comment Share on other sites More sharing options...
noumiere Posted October 29, 2018 Author Share Posted October 29, 2018 Hi there just wondering if anyone has any suggestions for this problem? Regards Quote Link to comment Share on other sites More sharing options...
Noobini Posted October 29, 2018 Share Posted October 29, 2018 at my level, I doubt I would be able to help but maybe others can help if you would further clarify the problem. So are you saying, if you have a knife, cutting the rope (while it's simming), you'd want the rope to be cut in half, so 2 pieces of ropes each dangling at each end attached to each cube....AND the 'strip' should also be cut in half and deform as per the 2 ropes ? Quote Link to comment Share on other sites More sharing options...
noumiere Posted October 29, 2018 Author Share Posted October 29, 2018 Thanks for the reply Noobini, let me clarify my question a bit better. Put simply : I have a simple plane that is being Translated downwards continously. I have an object that slices this plane and rips it into two. That's pretty much it, but to the nature of the plane (a plastic film strip) I wold like it to pile up a bit (as it is moving downwards) while it goes off frame. That's pretty much it I would greatly appreciate any pointers, currently I am still where I left off with the example in the first post - A wire solver using a Wire Capture to deform Geo but I can't for the life of me figure out how to fracture the wire and have the Geo do the same. Thanks! Quote Link to comment Share on other sites More sharing options...
Noobini Posted October 29, 2018 Share Posted October 29, 2018 well ok then, if i understand you correctly....it's quite simple, you'll need H17. Don't need the wires. The cutter does not have to be centered, you'll see i've offset it to the side a bit, adjust in the transform however you like, it will cut where you place the cutter. vu_cutter.hipnc Quote Link to comment Share on other sites More sharing options...
vicvvsh Posted October 29, 2018 Share Posted October 29, 2018 It's straightforward but it works cutting_wire.hipnc Quote Link to comment Share on other sites More sharing options...
noumiere Posted October 29, 2018 Author Share Posted October 29, 2018 Thank you immensely for taking the time to help me and provide examples. Both solutions have been extremely helpful, 9 hours ago, vicvvsh said: It's straightforward but it works cutting_wire.hipnc Vic, do you know how I would go about including an object that is stationary that the strip falls into once it is cut? Right now when I place geo and make it an RBD I can't get the strip to collide with it Thanks a lot 1 Quote Link to comment Share on other sites More sharing options...
vicvvsh Posted October 30, 2018 Share Posted October 30, 2018 It is not necessary to make RBD object. In this case use static object. cutting_wire_02.hipnc Quote Link to comment Share on other sites More sharing options...
noumiere Posted October 30, 2018 Author Share Posted October 30, 2018 7 hours ago, vicvvsh said: It is not necessary to make RBD object. In this case use static object. cutting_wire_02.hipnc Thanks so much for your help! Finally, do you know where I would key anination so the strip is cut while it is moving downwards? Would I key it in the Wire solver? Or the geo Thanks again for your assistance . I appreciate it Quote Link to comment Share on other sites More sharing options...
noumiere Posted October 30, 2018 Author Share Posted October 30, 2018 The issue is that pinto animation is on for the topmost points so even if the geo translates it is still bouncing back up Quote Link to comment Share on other sites More sharing options...
vicvvsh Posted October 31, 2018 Share Posted October 31, 2018 21 hours ago, noumiere said: Thanks so much for your help! Finally, do you know where I would key anination so the strip is cut while it is moving downwards? Would I key it in the Wire solver? Or the geo Thanks again for your assistance . I appreciate it If you mean animation strip geo then in SOP. Cutting strip in my example is taking place in DOP with keyframing "activation" parameter in wireglueconstraint1 dop node Quote Link to comment Share on other sites More sharing options...
vicvvsh Posted October 31, 2018 Share Posted October 31, 2018 21 hours ago, noumiere said: The issue is that pinto animation is on for the topmost points so even if the geo translates it is still bouncing back up Hard to tell without the scene. Would be easier if you attach your file. Quote Link to comment Share on other sites More sharing options...
noumiere Posted October 31, 2018 Author Share Posted October 31, 2018 50 minutes ago, vicvvsh said: Hard to tell without the scene. Would be easier if you attach your file. Thanks again for your time, I have attached the script and the objects. What I am trying to achieve is to cut the strip while it is moving downwards so that after it is cut, we see some of the strip that is still moving downwards. Basically like a projector film strip, if you cut it, the film strip will keep piling up a little bit I have attached the scene file For now what I have done is the extend the strip so that it is longer (to act like it is a long film strip) and I have keyframed transforms in the SOP. This doesn't seem to work, as you can see in the attached file. I have another problem where it isn't properly interacting with static objects. I appreciate your help cutting_wire_Test_v02.hipnc cutter.abc plate_1.abc plate_2.abc projector.abc spool_B.abc spool_L.abc spool_R.abc Quote Link to comment Share on other sites More sharing options...
vicvvsh Posted November 1, 2018 Share Posted November 1, 2018 I'll look at your file a bit later I'm a little busy right now Quote Link to comment Share on other sites More sharing options...
vicvvsh Posted November 2, 2018 Share Posted November 2, 2018 What I have done: in static object DOPs changed collision type from bullet to Use Solver Default. used proxy geometry for collision object because original geo is too thin for collision. changed some parameters in wire objects and wire solver. See by yourself. changed expression in wireglueconstraint1 bypass transform4 sop All new nodes I've marked green and nodes with changed params blue. Maybe I forgot something but anyway… cutting_wire_Test_v02_fix.hipnc Quote Link to comment Share on other sites More sharing options...
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