djpeanut Posted February 19, 2005 Share Posted February 19, 2005 I'm modelling a monkey (bipedal/quadrupedal) and have been working on the skeleton rig to begin with, as modelling over it will help me get the dimensions right. I've done a left arm and left leg and a simple spine. I'm a bit perplexed as to why my foot bones start to rotate when I move the whole rig upwards using the root object of the hierarchy (pelvis). I also encounter problems when I try and get the wrist mover to move with the rest of the rig - if I parent it into the network I am unable to move it at all! And in certain situations I will want to lock the wrist locations while moving the rest of the rig - is this what is known as FK/IK blending?? I'm not sure how to get this set up. Any other comments on what I've done so far would be hugely appreciated - this will be only my second character in Houdini (or any package for that matter). Suggestions would be great, especially on rigging the head/neck as I dont know how to get the head to articulate properly in all directions. skel_rig.zip Quote Link to comment Share on other sites More sharing options...
edward Posted February 20, 2005 Share Posted February 20, 2005 The problem is that you only want to inherit the translations from the leg to the foot. To do that, I made the following changes to your file: - Turned on the Keep Position When Parenting parameter in your l_foot_heel bone. I'm assuming here that you have the global Settings > Objects > Keep Position When Parenting option set to Use Object Flag (which is the default setting). - Disconnected the input into the l_foot_heel bone. This should keep your foot disconnected from your leg in the mean time without changing its world position because we turned on Keep Position When Parenting. - Append a Blend object to the l_foot_root null. Turn off it's select (brown) and display (blue) flags. In the Mask 1 parameter, toggle off all the buttons leaving only TX TY TZ turned on. This will cause only the translations to be inherited. - Connect the output of the blend object to the l_foot_heel bone. I've attached the modified file here. Hope this helps. skel_rig_2.zip Quote Link to comment Share on other sites More sharing options...
djpeanut Posted February 20, 2005 Author Share Posted February 20, 2005 Thanks edward, it's always a simple solution! Houdini's non-linear-ness takes a hell of a lot of getting used to. Definitely a programmer's program. I've attached my modified rig. Any suggestions for the wrist problem? skel_rig2.zip Quote Link to comment Share on other sites More sharing options...
edward Posted February 21, 2005 Share Posted February 21, 2005 What's the wrist problem? The thumb seems a bit wonky though. Quote Link to comment Share on other sites More sharing options...
djpeanut Posted February 22, 2005 Author Share Posted February 22, 2005 What's the wrist problem? The thumb seems a bit wonky though. 16409[/snapback] The wrist_mover controls the IK goal for each arm and controls the transform of the hand bone. Obviously this is OK if I want to move the rest of the rig but keep the location of the wrist static, but can I set up the rig so that I can switch to a setup where the wrist_mover moves along with everything else? I'll be needing to use both setups in the same scene. I'm stumped Quote Link to comment Share on other sites More sharing options...
edward Posted February 23, 2005 Share Posted February 23, 2005 Same answer. Use a blend object to switch between the parenting of the character hip's and a some dummy null (with default parameters). Now you can expose a parameter that can allow the animator to animate between the two things. PS. Where are the *real* rigger(s) who should be answering this? Quote Link to comment Share on other sites More sharing options...
calin_casian Posted February 23, 2005 Share Posted February 23, 2005 I put a little arm setup (the way I see it). That gives you is a local space (character space) ik handle and a world space ik handle. Your actual ik goal is blending between them thus it gives the animators more flexibiliy. You will notice that I 've separated the hand ik translation and the hand rotates for two good reasons: one is that while in fk mode you want to be able to rotate the hand and the other is that the hand should live in the forearm's space (gives you better rotations) not in world (ik handle space). Well I said 2 but there is another one if you care about squash and stretch. the hand rotate handle will always be at the end of your forearm bone (because it has a expresion in tz that takes the forearm bone length into account). The other thing is to create a real pole vector for the arm. For this I took the current ik goal and put another null tas a child and I made this null to lookat the arm root. next I add another null that has an expression in tz that calculates the distance between ik goal and arm root and position himself at the half distance. Now it's time to add the real twist effector as a child of twist_locator. You want tomove the twist in the direction of the elbow. I hope this helps and stay tuned on exchange because a lot of the rigging tools will be availabe as HDA. I'll do the leg in the same way. calin skel_rig3.hipnc.tar.gz Quote Link to comment Share on other sites More sharing options...
calin_casian Posted February 23, 2005 Share Posted February 23, 2005 about the programmer's program, I'm no programmer but I can tell you that I worked with maya for 6 years before touching Houdini and now I'll never go back to other 3d apps. I don't wanna start a war but H is so much better. Quote Link to comment Share on other sites More sharing options...
djpeanut Posted February 28, 2005 Author Share Posted February 28, 2005 I <snip> Mate, that's hugely helpful. Thanks. I've now rigged both arms using some of your techniques. The rig is posted in the Work In Progress forum. Quote Link to comment Share on other sites More sharing options...
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