eirik.m Posted September 19, 2011 Share Posted September 19, 2011 Hello friends! I am after a certain fracture effect. I have this skyscraper/tall building and I want it to fracture from top to bottom. Like a beam were to hit the top and the entire building would explode from top and down. You can see an example in the two videos at the top here: Example How can i do this effect in houdini. I have a plan on how to approach this, but I'm fairly new to Houdini, so it would be cool to see how others would approach this effect Thank you very much Quote Link to comment Share on other sites More sharing options...
Netvudu Posted September 19, 2011 Share Posted September 19, 2011 (edited) Well, if we are just brainstorming there are two ways I would usually approach this. One way would be to use a magnet force and metaballs to create that explosion-like motion. Another way, maybe more Houdini-like, would be to transfer the normals from a moving sphere as the velocity of your building pieces and use that velocity as the initial one for your pieces. That as long as the force goes. Regarding the progressive fracturing, there are several examples around this forums already...you should check those if you have any problems. Edited September 19, 2011 by Netvudu Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 19, 2011 Share Posted September 19, 2011 One way would be to use a magnet force and metaballs to create that explosion-like motion. Another way, maybe more Houdini-like, would be to transfer the normals from a moving sphere as the velocity of your building pieces and use that velocity as the initial one for your pieces. Hi Javier, So, what about gravity force? if we have a fractured object, and we have gravity in dops, it affects the whole object, not just those that are exploded by magnet force,and it will start falling down from the first frame! right? Quote Link to comment Share on other sites More sharing options...
Erik_JE Posted September 19, 2011 Share Posted September 19, 2011 Hi Javier, So, what about gravity force? if we have a fractured object, and we have gravity in dops, it affects the whole object, not just those that are exploded by magnet force,and it will start falling down from the first frame! right? If as in the example there is a "bomb" like velocity field animated in negative Y you could group the rbds that should be activated depending on the Y position and the radius of the "bomb". Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 19, 2011 Share Posted September 19, 2011 If as in the example there is a "bomb" like velocity field animated in negative Y you could group the rbds that should be activated depending on the Y position and the radius of the "bomb". Hi Erik, Yes, that would probably work perfectly for this purpose, but do you know any method to just activate those pieces that are affected by the so-called bomb? either it's another geo or a force? Quote Link to comment Share on other sites More sharing options...
Erik_JE Posted September 19, 2011 Share Posted September 19, 2011 Hi Erik, Yes, that would probably work perfectly for this purpose, but do you know any method to just activate those pieces that are affected by the so-called bomb? either it's another geo or a force? I don't remember if the example is on odforce, sesi forum or in the help but there is an example file where RBDs are activated depending on color in SOPs. So when they turn red they become active. That could be used for this kind of setup. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 19, 2011 Share Posted September 19, 2011 I think I know what you're talking about, is that the same one that uses foreach sop in it? if it's that one, it's on odForce. Quote Link to comment Share on other sites More sharing options...
Netvudu Posted September 19, 2011 Share Posted September 19, 2011 (edited) you mean, this one I uploaded? heheh. Gradual Fall It´s mostly ok for this example, but it will only work from top to bottom if you plan to make the whole thing fall. If you leave some part without activation, it will remain there mid-air, which obviously you don´t want to. But with a couple of fixes you could certainly use it for this purposes. It´s not the simplest thing to setup, but it does give an amazing artistic control over how a thing is going collapses. EDIT: Before I forget it, there´s also an example in the Houdini help called "Choreographed Breakup" which might be even better for this specific case. Be sure to take a look at it as well. Edited September 19, 2011 by Netvudu Quote Link to comment Share on other sites More sharing options...
eirik.m Posted September 20, 2011 Author Share Posted September 20, 2011 Thank you all! This has certainly given me some guidence I had a look at the Choreographed Breakup. And it seemed very useful. But if I were to use the Choreographed Breakup, how should I approach this with fractured objects? What I know and what I would do is: Make the building breakable and some kind of group the fractured objects and then add a rbdstate node which would unglue them after the plane passes through. But my expertise stops right after the make breakable step Could someone give some pointers on how to approach ? Thank you VERY much for your time Quote Link to comment Share on other sites More sharing options...
Netvudu Posted September 20, 2011 Share Posted September 20, 2011 It´s pretty much the same thing from the example, but using an RBD Fracture Object or RBD Glue Object instead of an RBD Point object. If you are working strictly from the shelf using the "Make Breakable", then maybe you should spend some time studying what the different RBD shelf tools do, so that you have a better insight on what´s going on there. Otherwise you´ll hit brick walls (fractured or not huh-huh ) every time you start a new project. My 2 cents. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 20, 2011 Share Posted September 20, 2011 (edited) hahaha... actually I didn't mean that one, but that's a good trick too! Edited September 20, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
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