View Full Version : Deform....

12 December 2003, 01:09 PM
Hi all,

I use ACS4 with weight map support to rig my character. but the result isn't very good on arms and thighs....

I've tried to use smartskin techs to correct some of the problems but the due to ACS4, some of the bone doesn't report the right bone angle.

I would like to solve that anyone helps? Sorry, don't call me not use ACS 4 because I've use it in another scene.

Steve Warner
12 December 2003, 03:42 PM
Hi Dick,

Can you post wireframe shaded and weight shaded screengrabs of just your character (before rigging)?


12 December 2003, 04:08 PM
I can only post wireframes of the character.

12 December 2003, 04:10 PM
Well, I know the I need to use smartskins to correct this sort of problem....But I don't know the Real HPB values of Arms and Thighs in ACS4.

Just using Weight Maps doesn't improve too much.

cousin it
12 December 2003, 05:29 PM
Use the 'Morph Mixer' deformation plugin to create animation channels for your endomorphs, then go to the 'Modifier' tab of the channels and apply the 'MorphDriverCF' lscript by faulknermano. This will allow you to control the endomorphs with the correct bone rotations, AFTER IK.

12 December 2003, 06:49 PM
Hi Dick,

I've just been playing around with the ACS 4 Demo, I think have now some more insight in using Smartskins with ACS4. As you found out already, the 'real HPB' rotation of the 'R_Arm' actually is composed of three bones, 'R_ElbowDir', R_ArmDir' and 'R_Arm', which makes it almost impossible to actually get the 'real HPB' rotation of the arm (if you want to avoid some complex trigonometrics). One idea which might be worth testing (even though it doesn't really solve the problem) are the following steps:
1. Add a child bone to the 'R_Shoulder' bone.
2. Do NOT record the pivot rotation or record the rest position of this bone, it is only a controller bone.
3. In the Motion Options panel of that bone, set 'Target Item' to 'R_ForeArm'. When you move the arm now, this bone will follow the movements of 'R_Arm'. You can now create two Smartskins with the heading and pitch axis of that bone as controller.
The big downfall of this solution is that it doesn't work anymore once you either rotate the bank axis of the 'R_Arm' bone or move the 'R_ElbowVector_Ctrl' null.

Generally speaking, Smartskins are IMHO not suitable for shoulders and thighs, as these bones rotate around multiple axes (in contrast to the forearm and shin bones, which only have one main axis), therefore I recommend using only weight maps.
Judging from your wireframes, you have enough geometry in the shoulder/thigh area so with some finer weighting that should be possible. Alternatively, you can also use muscle bones or some other deformation technique.

Hope that helps a bit.

BTW, your image shows an interesting visual style, great work !

12 December 2003, 01:56 AM
I would simply add in a hold bone or two. Stretch, move, rotate the hold bones to make those areas behave. You can keyframe them by hand or keyframe them and tie their behavior to a channel of another item via cycler so that it behaves automatically.

12 December 2003, 11:06 AM
Thanks all.

Now I utilize the weight map and some problems solved.

12 December 2003, 12:50 PM
If you have so high polygon model, it's always hard setup right weight maps.
I looked at your character and decide that a big amount of polygons are really not necessary for simple model as you had done.

have a look at image below.

12 December 2003, 03:25 PM
Well, the wireframe I posted has already simplied.. The original one is a subdivided one...because I would like to make some cloth wrinkles... But as you say, it is HARD to paint weight maps on ....

I see if I use a simplfied wireframe for bone deform preview, then add more details later on.

12 December 2003, 05:46 PM
The correct one, Like it ?

CGTalk Moderation
01 January 2006, 09:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.