Timm Dapper Posted April 1, 2008 Share Posted April 1, 2008 Hi there! I just started working with Houdini and while I think I got a good grasp on the basic principles, rigging this a lamp is alraedy causing me a little bit of a headache. Actually the first thing I thought about was setting the whole thing up using wire dynamics, but this is probably only suitable for certain parts and just stupid for others. The lamp is supposed to sit on top of a table that makes some pretty erratic movements and wiggle around (and perhaps even fall off the table - at least tumble around on it a little). This last part made me think, that I'd probably want to use RBD for the base. Then I figured that pretty much everything else is rigid as well (except for the cabling and the springs), so I kinda came to think that it's better to set this up with RBD, but then I wasn't sure how to set up the proper constraints for the triangular joints (which I think would've been a breeze with Wires). The RBD approach would also spare me of binding the geometry to the wire setup. I think I am pretty good ad finding my way through examples, web, books, tuts, etc. to get the setup finished, but it would be extremely helpful if any of the cracks here could give me a little pointer into the right direction (or a good direction, as in Houdini there's obviously always more than one way of doing things). I attached a screenshot of the corpus delicti... Best Timm Dapper Quote Link to comment Share on other sites More sharing options...
GallenWolf Posted April 2, 2008 Share Posted April 2, 2008 Hello! So basically what you want, is the lamp to react dynamically to a wobbling table right? I can't do any tests right now but what I can think of. - Use stand in proxy geo for your model. Then use the Dop Import SOP to transfer the animation data onto your final mesh. - Use a spring to maintain the bounciness in the arms. - wire for the power cord - You will probably need to up the sub sampling for the rbd solver too. I'll give it a go tonight. If I don't get distracted trying to fix my ubuntu driver problems :-/ HTHs! Alvin Quote Link to comment Share on other sites More sharing options...
Timm Dapper Posted April 2, 2008 Author Share Posted April 2, 2008 Hi Alvin! If I understand you corectly, you are suggesting going the RBD route + constraints for most things except the power chords. Makes sense. I made a first attempt on it (using proxy geometry) and got stuck pretty early. I just have a base and two arms, I hinge constrained the arms to the base, then tried to have another spring constraint between one of the arms and the base to retain the bounciness. The next step would have to add another constraint at the top of the arms, so they keep a constant distance to each other (or hinge constraint another connecting piece again). The spring constraint doesn't seem to play well with the other pieces. If I have it applied on its own, it's behaving as I expect. When I have it applied together with the hinge constraints, it doesn't behave well at all. Not sure what my problem is, this setup might be too naive in terms of interaction of constraints? Any idea? I attached my file so far... Best Timm Hello!So basically what you want, is the lamp to react dynamically to a wobbling table right? I can't do any tests right now but what I can think of. - Use stand in proxy geo for your model. Then use the Dop Import SOP to transfer the animation data onto your final mesh. - Use a spring to maintain the bounciness in the arms. - wire for the power cord - You will probably need to up the sub sampling for the rbd solver too. I'll give it a go tonight. If I don't get distracted trying to fix my ubuntu driver problems :-/ HTHs! Alvin lamp_test_001.hip Quote Link to comment Share on other sites More sharing options...
GallenWolf Posted April 3, 2008 Share Posted April 3, 2008 Tim, Sorry I was not able to check out your file - will do so when I get the chance I did however do a mock up yesterday, could you check it out and see if it works? Also, I haven't tried it but you could also use the wire solvers for the cord. And later in sops use perhaps the lattice sop or that-other-sop which I forgot to sort of skin it. Lemme know! Alvin rbdLampSim.hip Quote Link to comment Share on other sites More sharing options...
Timm Dapper Posted April 9, 2008 Author Share Posted April 9, 2008 Hi Alvin! This is pretty close to what I tried in my file. I had problems getting a stable solution, when I moved contraints around I sometimes had the simulation blow up, so I wasn't sure I was heading the right direction. Looking at your (really nice) example, I *was* moving in the right direction, though. Anyway, thanks for the great example! I have one question: Is there a specific reason for you using two pin constraints instead of a hinge constraint (which is what I was doing)? Best Timm Tim,Sorry I was not able to check out your file - will do so when I get the chance I did however do a mock up yesterday, could you check it out and see if it works? Also, I haven't tried it but you could also use the wire solvers for the cord. And later in sops use perhaps the lattice sop or that-other-sop which I forgot to sort of skin it. Lemme know! Alvin Quote Link to comment Share on other sites More sharing options...
GallenWolf Posted April 10, 2008 Share Posted April 10, 2008 No problem. Why I don't use the hinge constraint is because it starts with the latter H and ends in e. Nah, j/k. I don't use it 'cause I can't figure it out lol. Alvin Quote Link to comment Share on other sites More sharing options...
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