J.Santos Posted June 29, 2010 Share Posted June 29, 2010 Hi all! I'm trying to build a sandbag trench over a "rugged" terrain. I decided that the best way to make it look "natural" was to drop the bags from up high and let them conform (or rather deform) according to the terrain... But this is easier to think then it is to do, to me, of course... I tried using cloth but after some experiments I begun thinking that cloth is really cool to do... well... cloth simulations -> or similar stuff... My geometry kept being squashed 'till a line... but deformed !!! So then I went to RBD, converted the terrain to a static RBD and the sandbag to a RBD Object, looked through the info/help file and activated the Use deforming geometry and the referred Point Velocity parameter but... nothing happened! What do I need to do more? This is my first go at RBD so I must have made something wrong or haven't made yet some critical step... Thanks for the time to read this post and any help you can spare! Quote Link to comment Share on other sites More sharing options...
goldleaf Posted June 30, 2010 Share Posted June 30, 2010 That's not how RBD's work unfortunately. When you make an object an RBD object, it is considered one solid object. Using the 'Use Deforming Geometry' just means that the solver will look at the shape of the object on every frame, not just the creation frame, but it's still looked at by the solver as a rigid object. I think your first attempt with cloth is more along the lines of what you want to get done. I'm not very familiar with the cloth solver, but I think you need to put a few small spheres or boxes inside of the cloth bag to help it keep its shape. Quote Link to comment Share on other sites More sharing options...
Jason Posted June 30, 2010 Share Posted June 30, 2010 I could only see this working if each "sandbag object" was maybe a constained set of, say, three boxes next to each other -- kinda like a bit of a tank track. These could be deformers for sandbags perhaps? Quote Link to comment Share on other sites More sharing options...
Macha Posted June 30, 2010 Share Posted June 30, 2010 How about that? I am sure there must be a better way of doing this, because it is very inefficient and hard to control. sandbags.hipnc Quote Link to comment Share on other sites More sharing options...
J.Santos Posted June 30, 2010 Author Share Posted June 30, 2010 (edited) Hi! Thanks for all this input guys! goldleaf -> funny you say that of "stuffing" the bag with some objects... when I was looking at the sims I was thinking something like "Mmm... does Houdini considers the sandbags as only a shell, a empty bag?"... now I see I was thinking correctly! I just keep questioning me about how to use the spheres or boxes inside the bag... Will they be also a cloth? Nope because that would flatten them... a RBD object perhaps? Jason -> if the above idea of stuffing the bag doesn't work... I'll try yours! I was thinking also about metaballs and magnets... don't know if this makes sense, but it just appeared in my mind... Macha -> really a big Thank you for your file and all your work... unfortunately I got lost while reverse engineering a part of it so I can't use it... I can't fully understand it! I could just copy your nodes and all but I don't like to work that way... Thanks again guys! It's good to be in a community with this kind of feedback! Edited June 30, 2010 by J.Santos Quote Link to comment Share on other sites More sharing options...
J.Santos Posted June 30, 2010 Author Share Posted June 30, 2010 Hi guys! Just been checking and probably this can be done using a Squishy Object (looks like a gummy bear, on the "Create Particles" shelf... Quote Link to comment Share on other sites More sharing options...
ikarus Posted June 30, 2010 Share Posted June 30, 2010 (edited) what about stacking a few Sand objects together and have a really high viscosity/cohesion, if u have a good base volume you should be able to control the flow Edited June 30, 2010 by ikarus Quote Link to comment Share on other sites More sharing options...
Macha Posted July 1, 2010 Share Posted July 1, 2010 Hi guys! Just been checking and probably this can be done using a Squishy Object (looks like a gummy bear, on the "Create Particles" shelf... There was a thread here that deals with squishy object interaction (not resolved). If you get this to work it would presumably be very fast. Quote Link to comment Share on other sites More sharing options...
J.Santos Posted July 1, 2010 Author Share Posted July 1, 2010 Hi again! Ikarus -> I didn't knew that existed a sand object... I'll look into it, thanks for the "heads up". Macha -> Thanks for the link. I'll see it right away. I already achieved some "acceptable" results with squishy... But of course, it renders out as spheres so I'm thinking about "cooking/baking" the sim into the object... Will have to read a bit about it and test things up... Quote Link to comment Share on other sites More sharing options...
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