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Is there a guide to general weight mapping

MeneerWolfmanMeneerWolfman Posts: 421
in Technical Help (nuts n bolts)

I've been working on fixing weightmaps for a prop I was given. I'm finding that using general weightmapping is a bit like playing with one of those old liquid filled jelly balloons. Every time I  smooth out one part of a joint, something else carries over to a nearby joint and pokes out. If lock off the nearby joint, Daz will seem to get mad and not let make any changes to the joint that is not locked after a certain. I'm assuming Daz is trying to reach a certain value and if i go over that or under it it spreads it out to nearby joined to reach that number value.

To make it more infuriating, I'm finding this also affect to loading morphs with reverse deformations when the scale of the object is above 100%, the morph will get jagged and tear based on the weight map. However, if I dial the same morph in at a scale of 100% of the object, the reverse deformation morph takes with no problem or jagged edges on the mesh.

Is there a guide that will walk me through it?

Comments

  • Richard HaseltineRichard Haseltine Posts: 99,449

    Yes, you are correct. By default weights are normalised. That means that for any vertex the total weights across all the joints that affect it adds up to one. Adding or removing weight for one joint will have to take weight from elsewhere (to add) or add it (for removal) - reducing the weight pushes the excess to the parent bone.

  • MeneerWolfmanMeneerWolfman Posts: 421
    Richard Haseltine said:

    Yes, you are correct. By default weights are normalised. That means that for any vertex the total weights across all the joints that affect it adds up to one. Adding or removing weight for one joint will have to take weight from elsewhere (to add) or add it (for removal) - reducing the weight pushes the excess to the parent bone.

    Thank you, Richard, for confirming that. Is there any guideline for how best to apply it when starting out? Let's say you have 6 joint pole, is it best just to fill in each joint to the max and then smooth out the edges where each joint next to said joint meets?

    For debugging purposes (using the 6 jointed pole example). If I make a morph on joint 3 that cause the pole to have a bump, and when I dial that morph into the figure I see distortion on joint 2 that was not part of the morph, should I assume that means I underweightmapped joint 3 and some of that morph is going to join 2. Therefore I need to add more weight to joint 3 to get its value to 1?

    Also, does joint fully red = 1?

  • WillDupreWillDupre Posts: 71

    yes filling each group to 100% to start and than adjusting the weighting from there is usually the way to go(unless you are weighting a conformer which you will want to match the base figure to start). there is even an option in studio weighting to apply a starting weight for each group 'Fill by Bone Selection Group(s) '  

    where a morph shows up has nothing to do with Weighting. Morphs are simply instructions to move verts to new positions relative to the original positon of the vert. Weighting can affect how a morphed figure bends and you might need to create Joint controlled morphs to fix any distortion created by the bend, but thats a whole other kettle of fish. 

    and Yes Fully red does equal 1

  • MeneerWolfmanMeneerWolfman Posts: 421
    WillDupre said:

    yes filling each group to 100% to start and than adjusting the weighting from there is usually the way to go(unless you are weighting a conformer which you will want to match the base figure to start). there is even an option in studio weighting to apply a starting weight for each group 'Fill by Bone Selection Group(s) '  

    where a morph shows up has nothing to do with Weighting. Morphs are simply instructions to move verts to new positions relative to the original positon of the vert. Weighting can affect how a morphed figure bends and you might need to create Joint controlled morphs to fix any distortion created by the bend, but thats a whole other kettle of fish. 

    and Yes Fully red does equal 1

    Thanks, Will. Would the fact that the general weightmap also includes the scale weightmap factor into that?

    Part of the new found interest in weightmapping is I'm having an issue with morphs not loading correctly with reverse deformations if the prop's joints are at a scale other than 100%.

    e.g.: 

    1. Have a geograft prop that's scaled to 150%. Export it to Blacksmith. 
    2. Make some changes to the obj's mesh and save it.
    3. When I morph load it back onto the prop that's scaled at 150%, I get the changes I made, but I'm also seeing the mesh tear and move in other places.
    4. Tweaking the weight map seems to fix those changes "kinda"

    Strangely, if I dial the prop back to 100% and then morph load the change obj, it loads with the no issues and the prop takes on the new size and shape. 

  • Richard HaseltineRichard Haseltine Posts: 99,449

    Scaling should allways be reset in making morphs, as far as I am aware.

    General Weightmapping uses only the one map - alll the others are for TriAx weight mapping.

  • MeneerWolfmanMeneerWolfman Posts: 421

    But General Weightmapping also has a scaling built into it, right? Or is there not scaling included in the general weightmap, it's just xyz rotation?

     

    The issue I'm having is that the prop I'm working on has 6 joints and to increase the size of the whole shape the morph scales all 6 joints up to make the object bigger. If I build morphs after exporting the object scaled out, I've never had an issue importing the morph back into the scaled out object using reverse deformation. I was under the impression is that it looks at the two object's vertex positions and makes the target obj look like the source obj.

    I'm just really confused because it seems like when I try to reverse deformation load an obj that came from a scaled obj back to the scaled obj, it seems to be taking cues from the weight map for how it should load the morph.

  • Richard HaseltineRichard Haseltine Posts: 99,449

    I suspect your issue is the joint centres, not the weight maps.

  • MeneerWolfmanMeneerWolfman Posts: 421
    Richard Haseltine said:

    I suspect your issue is the joint centres, not the weight maps.

    I spent most of the day redoing the weight maps now that I better understand the process of general weightmaps. I have gotten the distortion issue 99% percent in check. There's just one trouble area where I dial in a morph near that area and the morph applies without tearing, but the area swells a little bit (almost like it was dialed in at 105%).

     

    Richard, what would you suggest I do for the joint centers, anything in the joint editor I should be looking for?

  • Richard HaseltineRichard Haseltine Posts: 99,449

    If you look at the figure with the Joint Editor active do the bones still line up with the body parts they control? I suspected from tthe scaling that they would not.

  • MeneerWolfmanMeneerWolfman Posts: 421
    Richard Haseltine said:

    If you look at the figure with the Joint Editor active do the bones still line up with the body parts they control? I suspected from tthe scaling that they would not.

    That they do. The bones are set up properly and the rigidity group editor settings seem correct. I have the transform bones set on the first bone of the geograft that is not part of or lying on top of the body. When I looked at it w/o being attached to the g8m figure it looks fine, as it does when graft. The tell tales signs (to me atleast) of bone joints being unaligned doesn't seem to be showing like bending the joints by themselves does not cause the mesh to tear or deform badly.

    A couple of lingering questions I do have thought with general weightmapping:

    1. What happens with the weightmap on the first bone after the hip bones if you underpaint it? The hip bone in most figures I've looked at have a weightmap but it's left completely unfilled. Is that to absorb any excess?
    2. How much of an effect does it have when you paint out areas not related to that joint in light blue? Using the 6 joint pole example again, if I painted the bottom joint of the pole mostly red, but then painted the top end with light blue to top off the bottom joint to one. If I  bend the bottom joint of the pole, how much of effect will that have on the top joint of the pole? Can one basically dump small amounts of unused weight on a distant joint to help even it out and not cause much disturbance to that far joint?
    3. Related to 2, I've not in my experimenting that sometimes instead of ending a map abruptly at the end of the joint if I paint out a long strand of blue it seems to disperse the weight from the original joint in a way that doesn't the blue painted adjointing joints. Is this a good technique for?

    Thanks to you and the other users who have kindly responded.

  • Richard HaseltineRichard Haseltine Posts: 99,449

    I meant do they line up with the morph applied, not in the base state.

    1. yes, unused weight would go to the hip as far as I know - it's usually unweighted because the weight has all been assigned to child bones.

    2. I'm not entirely shure I follow, but when you move a parent bone then the movement is transmitted down the chain so any child bones will move to the extent dicated by the sum of the weights from the parent and all other bones down to and including the child - which is why weight maps are normalised, to stop a vertex from ending up with a larger than 1 weighting and so flying off when the root node or a parent node is transformed.

    3. sorry, I don't understand

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