View Full Version : Newbie trying to weightmap. Need Help!
11-06-2004, 02:58 AM
I'm working on weight mapping a character that I have modeled, but I am pretty new to the whole process and am having difficulty getting my character to deform the way I want. I'm having the most trouble getting his wrists to bend properly. Specifically, I want to be able to twist the hand so that the palms are facing back (as if the character were looking at his own palms). The problem that I'm having is that the wrist collapses when I twist the hand to this angle.
First, here is what my character looks like:
And here is the problem:
Here is how I have set up my weightmaps:
I have found that if I twist the elbow in towards the body, the collapsing of the wrist subsides, but this isn't really a very viable solution, because I can't always have the elbow tucked in towards the body. Here is what that looks like:
Like I said, I'm pretty much a newbie at this (this is only the second character I've rigged; the first one had the same problems). As for my methods, I'm using Timothy Albee's book "LightWave 3D 7 Character Animation", so if you have any questions about why I did something the way I did, the answer is "because thats the way the book said to do it." I like the book, but felt that more information could have been provided about weightmapping.
As per the book's suggestion, I am using "Weightmap Only" with "Weightmap Normalization" turned on. Also note that the arms are IK. Since I am still learning to rig, I would appreciate any suggestions to improve upon my method. I am guessing that my problem is either that the wrist area doesn't have enough segments, or the weightmaps aren't distributed correctly (or both).
Thanks in advance for any help!
As per the book's suggestion, I am using "Weightmap Only" with "Weightmap Normalization" turned on.
I personally worked out other ways of do it.
In your case i would just selected All your hand/glove polygons
( with symmetry ON make both Hand weight maps at the same time :thumbsup: )
and hit create weight maps call it " hands"
do the same for the arms symmetry ON Selecting all the arm polygons and hit create weight maps
now go to Layout, assign all the bones to the new weight maps ( spreadsheet good for this ) and make sure you turn off "Weightmap Only" & "Weightmap Normalization"
do this and let LW's natural Bones do they magic Play with Fall off, strength and all the other controls in the Bone panel
now if you need some Hand weight to effect the wrist Now we have seen what normal Lw bone do we can go back to modeler just uses ( Fi's blur weight map plugins ) or uses air brush to paint a small amount ( or just select the points ) of hand weight map to the Arm weight maps.
hope this helps :thumbsup:
11-08-2004, 02:45 PM
I think you shoud try something I've learnt from Kurv's free tutorials (www.kurvstudios.com (http://www.kurvstudios.com)). to explain this shortly, split the lowerarm bone in two bones and use follower on the extra bone so you have the lower part of the forearm rotating by say 30% of your hand rotation. this makes the wrist rotating nicely without any problem. Concerning the other problems you mentioned, I think you can fix those by setting limits to your joints rotation.
btw, I love this character :)
11-08-2004, 03:22 PM
From the pictures I can see that the hand and the arm of your model are not connected. In that case it is a solution to have one weight map for the hand bone which has all points on the hand/glove set to 100% and on the arm set to 0 %. For the forearm bone you should have the arm points set to 100 % and the hand points set to 0%.
If you have arms and hands as one continous mesh, in a standard rig you would normally use the method that Weetos suggested, i.e. split the forearm bone in two bones and apply 'Follower' which lets the second forearm bone follow the bank rotation bone of the hand. I said 'normally' because in the Albee rig this method isn't really easy to accomplish, as in that setup the hand bone is NOT the child of the forearm bone. That is actually one of the reasons why I personally don't like the Albee rig, even though otherwise it is very light and intuitive to use.
11-08-2004, 11:56 PM
Thanks for the replies everyone.
Weetos, I'm going to try to my best to get this to work without adding new bones, but if I can't I will try the Kurv method.
Suricate and T4D, it seems like you are both suggesting something similar: setting the glove to 100% hand 0% forearm, and setting the forearm to 100% forearm and 0% glove, and then disabling weightmap only. I played around with that and got something that looks like this:
The problem is that the glove cuts into the top of the forearm and the bottom of the forearm is revealed. Playing around with the bone settings, I found that if I turn on Joint Compensation and set it to 100%, this problem is fixed:
BUT, when I rotate the hand around so that the palm faces the body, this has the opposite effect:
By setting the Joint Compensation to -100%, this fixes the new problem:
After trying these different settings, I still haven't found a solution that is satisfactory. I'm going to try a few more things before spliting the forearm bone into two as Weetos suggested. One thing I'm going to do is try to connect the hand to the arm so that it is one continuous mesh.
If there are more suggestions, please keep them coming. Thanks!
11-09-2004, 01:48 AM
Unfortunately Tim's book doesn't explain how to avoid problems like this at the wrists. For the best results you'll need to have at least two bones in the forearm.
11-09-2004, 02:07 AM
Unfortunately Tim's book doesn't explain how to avoid problems like this at the wrists. For the best results you'll need to have at least two bones in the forearm. Yeah, my biggest complaint about the book, which on the whole I found quite useful, was that the weightmapping chapter didn't go into enough detail. Also, I'm finding that more bones in the forearm are necessary, so I'm going to start working on this now. Does anyone have a favorite rigging tutorial they can recommend? I'm about to check out the one at kurvstudios that Weetos suggested, but are there others? Is there one that is universally considered the best? I have looked into using simplerigger, but don't know if that is a particularly good rig or not.
Thanks for all help!
11-09-2004, 02:13 AM
I would set up the bones with a falloff of ^128. Initially I wouldnt use ANY weight maps. Rest the bones and then test it out to see where you might need weight maps. Sometimes youll only need a hold bone or two. Lightwave bones work immediately as soon as you rest them. Many times you dont even need weight maps but waiting until the end to use them will insure that , if nothing else, are simpler then creating a weight map for every bone. I have never ever had to apply weight maps for every bone and Ive also never had to use "weight map only".
01-19-2006, 08:00 PM
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