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Joint problems
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Joint problems // Archive: Tech Forum
Post by Burnart // Sep 24, 2007, 1:35pm
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Burnart
Total Posts: 839
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Picture 1 - shows the hand of my alien model. I have rotated the wrist but the zone of influence around the joint is so shallow that the mesh crumples badly. The goal therefore is to try extend the zone and give it some fall-off so that the rotation is smoothed across the mesh.
Picture 2 - I tried to use the weight paint tool to extend the yellow coloured vertices from the hand bone up the wrist but when I exited the bone weight tool I got these weird lines extending everywhere. I persisted with trying to work with the model. When I moved the model in dynamic pose mode the lines did disappear - but then so did the menu bar with the dynamic pose tool!
Question 1 - is this a known bug or a problem of my own creation?
Question 2 - how do I create better (crumple free) joint rotation? The mesh on this model is reasonably dense.
Question 3 - I'm trying to rotate the joint in dynamic pose mode by clicking on the joint and using the rotate widgets (as in picture 1) - is that the correct way to do it? |
Post by jamesmc // Sep 24, 2007, 1:44pm
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jamesmc
Total Posts: 2566
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Is the mesh dense around the areas where the problem is? |
Post by trueBlue // Sep 24, 2007, 1:55pm
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trueBlue
Total Posts: 1761
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It looks like you have stray vertices that have not been painted. With the Dynamic pose tool manipulate these areas until they start popping out and then paint them back into place with the Weight Paint brush. Make sure you set the default pose first if you have not done so. |
Post by Burnart // Sep 24, 2007, 3:14pm
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Burnart
Total Posts: 839
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It looks like you have stray vertices that have not been painted. With the Dynamic pose tool manipulate these areas until they start popping out and then paint them back into place with the Weight Paint brush. Make sure you set the default pose first if you have not done so.
Thanks for the thoughts - I can't try until I get back home! I thought that I had done pretty well with the painting, approaching it from front, back, top and bottom. Unpainted vertices must be very difficult to spot. Also I don't get why unpainted vertices should leap off to infinity when I exit the dynamic pose tool! If that is the case then it must be some kind of bug surely? |
Post by 3dpdk // Sep 30, 2007, 6:47pm
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3dpdk
Total Posts: 212
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This was a problem with old tS bones (pre 7.x). If you try editing muscles and/or tendons or bone affecter zones and right click your mouse on an empty portion of the screen to exit edit mode, vertices fly off in every direction ... sometimes! That's the problem, it's not a consistent problem or behave the same way every time it does show up.
My impression (and that's all it is - an impression) is that its linked to the calculations involved and the available memory you have on your system for tS to do those calculations. A high poly mesh will fault like this sooner and more often than a low poly mesh.
Also if you move the rigged mesh anywhere but where you first attached the skin, then enter any edit mode for the skeleton (it actually happens when you exit an edit mode!?!)- poof - you have a nasty tangle of vertices. I noticed this recently while trying to evaluate the trial version of 7.5 Much older tS was prone to this problem with point edit mode also. For some reason some of the vertices want to return to ground zero. If they all went back to their origin it would be no problem but it's usually only a percentage of them that will move.
The lesson I learned in tS6.6 when rigging a mesh with tS bones was to completely set up the skeleton's joint limits and vertex weights before testing. If you set up, say, an arm, test it, then set up the other arm, test it, then move on to the chest and body, test it, etc, you are more likely to cause this error, especially if you move the model, even slightly, from it's original position.
If you can locate the stray vertices and have the patience, you can return them to where they belong. Other than that I recommend you back up to an earlier saved mesh. Especially if the wild vertices don't show up in a render it means the mesh is now faulty with bad geometry and any further editing will only make matters worse and for heave's sake don't ever click "undo" when this happens. Any animating and rendering with a faulty mesh will eventually hard crash tS and make the scene completely un-loadable.
This is all based on 6.6 but since the result seems to be the same it probably holds true for 7.5
Paul |
Post by tomasb // Oct 1, 2007, 2:06am
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tomasb
Total Posts: 261
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Question 1 - is this a known bug or a problem of my own creation?
if you weight paint model and then adjust control mesh (edit it) then changed vertices are detached and they need to be weight painted again. The same problem happens when you for example skin SDS mesh and after attaching skin you change subdiv level - skinning algorithm in both cases don't know skinning weights for changed geometry.
Question 2 - how do I create better (crumple free) joint rotation? The mesh on this model is reasonably dense.
create 2 joints instead of one and set it to rotate only around Z. this way you get rotation deformation extended to much bigger area.
Question 3 - I'm trying to rotate the joint in dynamic pose mode by clicking on the joint and using the rotate widgets (as in picture 1) - is that the correct way to do it?
selecting joint activates NAV widget which is used for FK. Only IK handles can be selected and manipulated by nav widget. |
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