How To Mirror Skin Weights Maya

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Skinning in Maya

Today nosotros are going to be skinning a leg. Before getting started, download the leg rig to the scenes directory in your current Maya project.

What is skinning?

There are ii ways to bind geometry to a rig.
Constraints allow you to connect separate pieces of geometry to individual articulation(due south) in a rig. This is adept for robots, mannequins, machines, or things that are fabricated up of different moving parts. Your geometry itself will not bend or change shape. Recollect of your geometry as pieces of forest joined by hinges.

Skinning allows y'all to connect one large slice of geometry to a skeleton and designate how much influence each joint has over each vertex in that mesh. Think of your geometry similar a condom outer "skin" that follows the movement of the joints. This is good for organic models like people and animals. The joints "influence" or put "weight" onto a vertex and vertices and by altering the values, y'all can create naturalistic organic deformations.

Influence on a vertex is designated on a scale of 0-i for every articulation. 0 means that that vertex will non follow the joint at all, 1 means that the vertex will follow the joint completely. Then if there are two joints in a skeleton, and a vertex is receiving 0.half dozen influence from articulation i, then that vertex must also be receiving 0.iv influence from joint two. The process of skinning is assigning or "painting" influence values onto sections of geometry.

Before You Start

Double cheque that a skeleton is in the proper identify. Properly placed joints are important to make sure your character (if you are skinning something, information technology volition probable exist an organic grapheme) moves realistically. Two common mistakes:

1. Shoulder joint isn't placed far out enough. Feel your shoulder joint as you motion your arm up and downwardly. Encounter how the joint is located pretty much straight up from your elbow? If y'all put it where your collarbone is, your characters shoulders will cave in.

ii. Non enough vertexes. Because skinning depends on influencing vertices, not having enough vertices means yous have less control over how the mesh deforms with movement. Be certain you have at least iii border loops around wherever y'all have a joint (elbows, wrists, knees, hips.) Spines are less worrisome when it comes to edge loops because you don't bend the waist the same manner yous bend at your human knee or elbow, then you probably merely need ane loop.

3. Be sure to proper noun everything. It'south very piece of cake to lose rails of your skin weights considering Maya volition automatically set up combinations of weights to equal one. You will have a very unpleasant time if y'all don't name everything.

4. Freeze transform and delete history on your mesh. You CANNOT practise this later, considering information technology will ruin your skinning.

Initial Skinning

Get-go, we'll let Maya endeavor to skin the geometry. It will estimate the peel weights based on the distance between the joint and the peel. Select the Root articulation of your skeleton, and select the geometry. Go to Peel --> Bind Pare --> Smooth Bind. Set the options to the following. Make sure your settings for "Normalize Weights" are on Interactive.
And so select Bind Pare.

The skeleton should show upwardly every bit different colors--this indicates the skeleton is bound. (Maya isn't very good about indicating this, if you delete the skin demark the color will oftentimes stay there regardless...this isn't really an issue, just a thing of display!) Select the mesh and expect in the channel box: 1 of the inputs should be skinCluster1. This indicates that the skeleton is at present bound to the mesh. IF YOU DELETE HISTORY AT THIS STEP, It WILL DELETE YOUR Skin CLUSTER, AS WELL AS ALL THE WORK YOU'VE Done SKINNING. So don't practice that!

Motion the legs around with the controls. See how weird this looks?

Moving the left leg skeleton pulls at the skin on the right leg, and vice versa. Then at present, we'll offset painting peel weights correctly to fix this.

Painting Skin Weights

Make certain your shelf category is on animation. Select your skinned geometry and go to Pare → Edit Smooth Pare → Paint Skin Weights Tool → Selection Box
Check out the tools in the option box. Make sure "Normalize Weights" is set to Interactive. This designates the way Maya calculates the influence of each joint on a vertex as a percentage of the total influence on that vertex, also known as "normalizing" the weights. (don't worry about this, you'll never really need to change this pick.) Make sure you have the other options set correctly, every bit shown below.

Look at your model. It should have different shades of grayness on it. This indicates how much influence that vertex has from the selected joint. Black means 0, or no influence, white means 1 or full influence, Scroll down to Gradient and check the option to "Use Colour Ramp." This is easier manner of displaying the weights: Blackness is still 0, white is all the same 1, just yous become a rainbow range for in between that is easier to wait at then a range of grays.

You lot accept options to change the shape and softness of the castor, and unlike ways you can pigment weights: Replace, Add together, Scale, and Smooth.

You can see all your joints in the box in the toolbox nether the label "influences." Retrieve of all your joints as sources of influence that put "weight" on the vertices. Kickoff by locking all the joints in the list. Select the first joint, and then shift-select the last joint, and click the little xanthous lock icon at the bottom. Locking a joint prevents you lot from adding or removing weight values from the articulation. Because adding influence from i articulation means subtracting influence from another joint, make certain that yous only have two joints unlocked at any moment. Otherwise you might end up with 1 vertex with 0.one influence from ten joints. This gets very disruptive.

There are four methods to pigment weights:

Supplant

When in the "Supercede" mode, whatsoever weight yous pigment will exist the weight that is specified past Value. It takes the influence from other unlocked joints. This is why it's of import to merely unlock 2 joints at a time. Then if yous pigment with a value of 0.iv, the other unlocked joint will receive a value of 0.half dozen.

Add together

When in the "Add" mode, any weight you paint will be added to the current influence. Whatsoever amount added will be subtracted from the other unlocked joints.

Scale

When in the "Calibration" mode, the current weight will be multiplied past the Value. So setting Value=1 will have no consequence, Value=0 will replace the influence with 0, and Value=0.5 will divide the weight by 2, so 0.8 will become 0.four and .6 will become .three, etc, etc. Very useful for when we want smoothen connections between 2 joints and some other joint, as well as between those two joints.

Smoothen

When in the "Polish" fashion, the weights beyond several vertices volition be smoothed out, as well as the unlocked joints. This is very useful!

Overflowing

The "Flood" button basically applies whatever settings y'all have gear up to the all vertices. Information technology will just affect the unlocked joints. Then if yous want to move all the influences from joint 1 to joint 2, yous would unlock merely those ii joints, and with joint 1 selected, with performance set to Supersede and Value fix to 0, and then click "Overflowing". Now all influences from joint i are transferred to joint ii.

Block Skinning

This method basically erases all of the weights assigned by automatic skinning, and relocates all the influence so your unabridged mesh is only affected past one joint (usually the root). And so, you lot remove weights from the root onto each articulation, one by i. This is the easiest way to skin something because its easy to continue track of where you are subtracting all of your weights from, as you add weights to joints.

REMOVE EXISTING WEIGHTS
1. On the legs, unlock Root and LHip.
ii. On LHip, set the paint mode to Supplant, the value to 0, and the brush opacity to i. Click inundation. LHip is now has no influence on the mesh whatsoever.
three. Click back to root. It should announced as if Root has all the influence that LHip used to have.
4. Lock LHip again. Keep Root unlocked.
5. Unlock LKnee. Proceed the same paint manner, click overflowing again. Now LKnee has no influence on the mesh either. Click back to root. It should expect similar the Root has likewise gained those weights. Now lock LKnee again.
6. Repeat with all the joints, unlocking, flooding, and locking them again.
7. Once you're washed, select Root. The entire mesh should exist white. The root joint has all the influence over the unabridged mesh. If you move the leg controllers, the leg geometry will not move with the skeleton, because those joints are not affecting the geometry at all.

PAINT NEW WEIGHTS
8. Now unlock LHip again. Set the paint way to Replace and the value to ane. Pigment the upper leg white (doesn't have to exist perfect). Lock it once more afterwards. Click Root. See how what y'all just painted on LHip is now black?

ix. Echo with LKnee, LAnkle, LBall, LToe, the way they are in the pictures. Be sure to continue ONLY the joint you are skinning and the Root joint unlocked at whatever given time.

10. Afterwards you are washed with the left leg, click on the Root Joint to make certain you haven't missed whatever spots. In that location should be no white spots anywhere on the left leg on the Root Joint. If there is, that means the Root notwithstanding has influence on that vertex, and it will brand your leg move weirdly. Unlock the joint that should be influencing that vertex, and prepare that spot.
xi. Select the skin and go to Peel --> Edit Smooth Skin --> Mirror Skin Weights --> Selection Box, and make sure you have the correct settings (nigh likely, your model is symmetrical across the YZ centrality, and you painted the left side, so y'all mirror positive to negative). Click MIrror.

12. Go back to the paint skin weights tool and scroll through all the joints in the tool box. Y'all'll see that mirror weights put all the weights on the left side on the right side too. Move your controllers effectually. The leg meshes should movement independently now. But, you'll notice that motility the leg too high, and the articulatio genus will intersect with itself. This is considering we have very rough, block skins. We need to smooth out the weights.

Refined Skinning

13. Go to the Pigment Skin Weights Tool. Unlock the Root and the LHip. Click on either articulation. Using the Smooth paint mode, paint over the edges of the white area. This creates some falloff in your weight values, then that mesh that is very close to the Root joint has an weight of 1, but mesh further away from the root joint might have an influence of 0.5. It doesn't thing what joint you click on, because the smoothen values will occur in the aforementioned identify on the other articulation every bit well. If you paint a vertex that is betwixt the Root and Lhip to have 0.5 influence from the Root, it will also accept 0.five influence from the hip.

14. Practise this for the entire left leg, unlocking but ii joints every time and smooth the expanse between them.
xv. Mirror your weights again to motion them to the other side.
16. Tadaa! You have a pair of skinned legs that move realistically! Play with and tweak the skinning in places that might still intersect. Yous tin use skinning to mimic the style the back of your human knee deforms when yous bend information technology.

Random Pro-Tips

- Unlocking all your joints, and flooding the Root with 1 is a quick mode of zeroing out everything else. Just be certain yous lock everything support after.
- Sometimes Maya is stupid and won't let you pigment something to zero, even when yous have merely 2 joints unlocked. After skinning a joint its a adept idea to go dorsum to it and make certain the weights were actually successfully painted on. If a articulation won't let you pigment out its influences, go to your other unlocked articulation and pigment on a value of 1. Information technology will make the other ane 0.
- I really rarely use cake skinning. I commonly employ Maya's Shine Bind, and remove the wrong weights by unlocking the right joints. However, if you lot don't keep track of which joints you lot accept unlocked, Maya will randomly readapt your weights onto multiple joints and you'll have a terrible time trying to figure out where all your influences are. I ALWAYS cake skin finger joints, because I tin can't keep rails of twenty joints on each hand.
- If you demand to adjust your mesh or joints afterward you lot've skinned, first, salve your file and duplicate it. In the copy, go to Skin-->Disassemble Pare-->Option Box. Select Proceed History from the Drib Down menu, and click Detach. Practice Non delete your history...information technology will delete all your skin weights! Duplicating the file get-go is a good idea considering 9 out of 10 times this method will work....but you don't want to risk that one fourth dimension it doesn't and you take to reskin everything. With the mesh discrete, yous tin can accommodate joints, and geometry, simply if you add new joints or vertices you will have to tweak the pare when yous reattach information technology. If you already have your UV maps completed, you tin can export your peel weights as prototype files, and import them again later. This method ensures that you lot will not lose your skin weights, simply you volition have to UV map your models beginning.

Good luck! :)

Written past Michelle Fang
Based on original tutorial by Megan Marquardt