aracid Posted August 4, 2009 Share Posted August 4, 2009 Hey Guys Soo I was wondering if anyone had any idea how to get a pile of marbles (or sand.. cough cough) RBD's to react to paper being pulled out from underneath them, naturally if one does this fast - u left with this pile on your desk and the paper in ur hand, and the slower u go, the more u can bring along with u - ie classic case of inertia how can i fake this, or more like, I'm stuck with something from the animation department that accelerates really quickly and this pile literally cant keep up. just setting a high friction doesnt work, even with a thin film of marbles, they seem to stay behind. Is there something specific i need to do to achieve this, or an area of either the obj RBD (mass, friction) or the solver that can help deal with this? ive tried using the velocity of the animated object as a field force and driving the rbd's intially with this, but it seems like a hack. any ideas would be great brian Quote Link to comment Share on other sites More sharing options...
pclaes Posted August 4, 2009 Share Posted August 4, 2009 ive tried using the velocity of the animated object as a field force and driving the rbd's intially with this, but it seems like a hack. That's what I was thinking to do as well. On top of that field force you could also turn the animated object into a volume and use the gradient of the volume to help as an attraction force for the other objects. (Like turning the entire sheet into a big magnet). Perhaps this sort of thinking could help as well: if you pull a smooth and even piece of paper from the pile of sand, the sand stays behind. If you pull a crumpled piece of paper from the pile, there might be more friction and more would come along. So deforming the animated sheet of paper with a mountain sop or so might make it less smooth and therefore cause more friction, dragging more sand along. just my two cents Quote Link to comment Share on other sites More sharing options...
Matt_K Posted August 5, 2009 Share Posted August 5, 2009 Hiya Brian! As a quick idea - what about a pin constraint on the marbles that lasts for a single frame to give that initial pull? Later! Matt. Quote Link to comment Share on other sites More sharing options...
aracid Posted August 9, 2009 Author Share Posted August 9, 2009 Hey Guys I never got around to doing this, they ended up using physx... sadly Thanks for the help tho Quote Link to comment Share on other sites More sharing options...
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