chrsmith Posted July 16, 2009 Share Posted July 16, 2009 Hi all, I'm animating a airplane doing air-to-air refueling with a hose and drogue setup as seen in this photo: (url: http://farm3.static.flickr.com/2035/372561...da355da21_o.jpg ) Basically, when the airplane that's getting fuel connects, it pushes in slightly, creating slack in the hose, and there's also a little u-bracket between the hose and the basket that rotates on a hinge. I set up 3 bones for the hose to flex, a bone for the u-bracket, and a bone for the basket all in one chain. I put a handle at the bottom, added a target, and I created a handle chop as described in Houdini's help for the handle object. I'm kind of stuck at this point. I can move the target and the contraption flexes, but I don't see where to put in following constraints: The u-bracket should only rotate in one axis. The basket shouldn't rotate. I'd like to be able to push it in in Z to create the slack down the chain. Everything should be rigid except for the hose. Any tips, suggestions, or tutorials I should look at? Thanks, Christine Smith Northrop Grumman Engineering Visualization Resource Quote Link to comment Share on other sites More sharing options...
edward Posted July 16, 2009 Share Posted July 16, 2009 Here's a rough attempt attached using 3 InverseKin CHOPs. I think you would need to be careful to not weight anything to the "basket_bone" though. hose_rig.hip Quote Link to comment Share on other sites More sharing options...
chrsmith Posted July 16, 2009 Author Share Posted July 16, 2009 Here's a rough attempt attached using 3 InverseKin CHOPs. I think you would need to be careful to not weight anything to the "basket_bone" though. Wow! I can't believe you actually rigged up something! Thanks! I'll put it together with my geometry and let you know how it goes. Christine Quote Link to comment Share on other sites More sharing options...
michael Posted July 16, 2009 Share Posted July 16, 2009 HAHAHAHAHA! I guess you mean you're surprised that someone rigged something for you as an example and not surprised that Ed actually was able to rig something 1 Quote Link to comment Share on other sites More sharing options...
chrsmith Posted July 17, 2009 Author Share Posted July 17, 2009 OK, got it! Had a couple of problems, though: 1. As soon as my aircraft moves, it breaks. The bones, goals, and geometry are still in their relative positions, but it's not deforming the geometry unless I'm on the frame/position where I first set it up. Any idea what causes that? I worked around it by doing the deformation in place and doing an object merge of it and parenting it to the tanker. 2. I also couldn't get the rotation of the u-bracket to work without it deforming and tapering, so I excluded it from the deformation and I'm keyframing that part. Thanks! You got me a good starting point. Christine Quote Link to comment Share on other sites More sharing options...
edward Posted July 17, 2009 Share Posted July 17, 2009 1. As soon as my aircraft moves, it breaks. The bones, goals, and geometry are still in their relative positions, but it's not deforming the geometry unless I'm on the frame/position where I first set it up. Any idea what causes that? That sounds strange to me. Can't really tell without seeing how you've attached your geo to the bones. 2. I also couldn't get the rotation of the u-bracket to work without it deforming and tapering, so I excluded it from the deformation and I'm keyframing that part. Yeah, there's definitely parts of that which shouldn't be captured. I was hoping you would only need to keyframe the two null controllers though. Quote Link to comment Share on other sites More sharing options...
michael Posted July 17, 2009 Share Posted July 17, 2009 can you post a small example of your file? this setup shouldn't be too difficult... Quote Link to comment Share on other sites More sharing options...
chrsmith Posted July 17, 2009 Author Share Posted July 17, 2009 can you post a small example of your file?this setup shouldn't be too difficult... Easy for you, difficult for me! (I don't do IK very often.) Here you go. It has my object merge to fix the problem of the deformation breaking when the tanker moves. The deformation still isn't perfect, especially around the u-bracket. refueling_setup4odforce.hip Christine Quote Link to comment Share on other sites More sharing options...
michael Posted July 17, 2009 Share Posted July 17, 2009 geo file sops are broken... is there a reason the deformation-setup is 10,000 units away from the tanker? Quote Link to comment Share on other sites More sharing options...
chrsmith Posted July 17, 2009 Author Share Posted July 17, 2009 geo file sops are broken...is there a reason the deformation-setup is 10,000 units away from the tanker? I thought for sure I had locked the file sop. Here it is locked: refueling_setup4odforce_v2.hip The deformation setup was done on wherever the tanker was on the first frame of my animation. In hindsight I'm sure that's not the best practice, but I don't see why it should matter. For the simple version I saved for sharing, I put the tanker at 0,0,0 and put in a simple animation in tz. Quote Link to comment Share on other sites More sharing options...
michael Posted July 17, 2009 Share Posted July 17, 2009 cool... this should be pretty easy...I'll have a look when I get home and post a file. Quote Link to comment Share on other sites More sharing options...
chrsmith Posted July 17, 2009 Author Share Posted July 17, 2009 cool...this should be pretty easy...I'll have a look when I get home and post a file. Don't bother unless you're really curious. I'm actually rendering now. I'm in a time crunch, and as we say at the office, "It's good enough for government work." Christine Quote Link to comment Share on other sites More sharing options...
edward Posted July 18, 2009 Share Posted July 18, 2009 The deformation setup was done on wherever the tanker was on the first frame of my animation. In hindsight I'm sure that's not the best practice, but I don't see why it should matter. For the simple version I saved for sharing, I put the tanker at 0,0,0 and put in a simple animation in tz. I think the deformation is screwing up by the scaling at on the deformation-setup subnet. The way I would have done it is to leave the transform on deformation-setup at their default values. Then make the tanker object a parent of the hose_root1 null (via parenting of the subnet). I'm also not quite sure about have the drogue object wired into the first subnet input. You might need to disconnect that. Quote Link to comment Share on other sites More sharing options...
michael Posted July 20, 2009 Share Posted July 20, 2009 hrrrmm... well better late than never... I've been having weird video card issues (if I change my viewport to a side or front view I can't change back ) anyway here is a quick file with otls... refuel_test.zip and here is a quick vid: refuel_test.mov the only reall interesting thing is the fetch and blend nodes...they allow you to switch the parent of the IK goal from the basket to the jet spouty thing... oh and don't let me catch anyone selling my awesome jets on turbosquid!! Quote Link to comment Share on other sites More sharing options...
chrsmith Posted August 20, 2009 Author Share Posted August 20, 2009 Hey all, Well, I THOUGHT I was done, but after showing him previews, rendering, and making a final video, my customer then said the hose should not hang so low and asked me to make a change. So I've adjusted the hose to his liking, but now I have to change the rig too, and I don't see how to do it. I can easily change the bone length, but what about positions and rotations? Changing the values in the "Bone Capture Pose" parameters don't seem to do anything. I'm pretty sure I shouldn't have to re-rig the whole thing from scratch. Help? hose_hang_change.bmp BTW: Thanks for your input and video, Michael! I didn't see your post until just now. Christine Quote Link to comment Share on other sites More sharing options...
michael Posted August 20, 2009 Share Posted August 20, 2009 you can move your bones with the bones tool, temporarily remove the path the the IK solvers first, and then use (in the textport) bonealigncapture -c * to fix the capture position...then move your controlers... if you have any trouble let me know - or post the file if you can and I'll see what I can do - it's not difficult, just involves a few tricky steps... PS: somtimes it's best to see if you can make model changes with the rig first - saves some trouble sometimes Quote Link to comment Share on other sites More sharing options...
chrsmith Posted August 20, 2009 Author Share Posted August 20, 2009 You know, you're right. Deforming it using the rig is probably the easiest. Quote Link to comment Share on other sites More sharing options...
michael Posted August 20, 2009 Share Posted August 20, 2009 good to hear... Quote Link to comment Share on other sites More sharing options...
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