Character Seams
Character Seams cuts the UV seams of a humanoid character, so a later unwrap lays out the face, the body and every limb as separate, predictable islands. You place the same nine markers as Auto Rig, and the node cuts the character at its joints and down the middle of each body part.
Why cut seams
Section titled “Why cut seams”An unwrap flattens a mesh into a UV layout, and it can only lay the surface flat where it is allowed to cut. Left to guess, an automatic unwrap cuts wherever the surface curves, which on a character means hundreds of small islands and seams across the face. Character Seams decides the cuts the way a texture artist would: at the joints, where a seam hides, and down the side of each limb. A later unwrap then gets a face, a body and limbs that each lie flat as one or two islands you can recognize and paint.
The node only cuts the seams; it doesn’t unwrap. Follow it with Auto Unwrap and set its Seams to seams: each half between the cuts is laid out as one island where it can be, so the face, the body and every limb come out as islands of their own. Where a half would stretch, Auto Unwrap cuts a short slit into it, and splits it only if that isn’t enough — spiky hair usually ends up in several pieces. Smart UV doesn’t read the seams.
What it does
Section titled “What it does”Nine loop cuts (neck, shoulders, wrists, hips and ankles) cut the character into ten parts: head, torso, two arms, two hands, two legs and two feet. A side plane through each part splits it into two halves: front and back for the head, torso, arms and legs, palm and back for the hands, sole and top for the feet. Every island between the seams lies flat.
The output carries the seams as the edge group seams (and the few added only so every island lies flat as extra_seams), and each part as a face group (head, torso, arm_l, …, foot_r).
Loop cuts
Section titled “Loop cuts”A loop cut is a plane at a joint, square to its bone unless you tilt it. It cuts only the loops of surface that wrap its bone: the wrist cut goes round the wrist and its sleeve, but leaves the hip it passes beside whole.
Turn on Cut through everything for a cut when the character’s surface is fused across it. The usual case is hair fused to the neck and shoulders: the neck cut finds the loop round the neck, but the hair still joins the head to the torso, and the node warns that the two meet without a seam. With Cut through everything on, the neck cut cuts every loop its plane crosses, the hair included.
Side planes
Section titled “Side planes”Each part has one side plane, running along its bone through the middle of the part’s surface:
| Part | Splits it into |
|---|---|
| Head, torso, arms, legs | front and back |
| Hands | palm and back |
| Feet | sole and top |
A side plane only cuts where it runs from one loop cut to another, so a curled fingertip or a tattered hem that the plane grazes stays whole. Side roll turns the plane about the bone and Side offset moves it off the middle, for example to hide the torso seam further back.
Islands that lie flat
Section titled “Islands that lie flat”An island can only lie flat if it is a disc: one outline and no holes or handles. When an island isn’t (a hole left by a missing eye, a strap looping back onto the body), the node adds the shortest extra seams that open it up, and lists them in extra_seams as well as seams.
Separate pieces of the mesh, such as eyes or hair cards, join the face group of the part they are closest to.
Warnings
Section titled “Warnings”An amber note on the node says when something needs your attention:
- A cut found no loop around its bone: the marker for that joint is off the body, or the limb is missing. Check the markers in Skeleton mode.
- Two parts meet without a seam: usually hair or clothing fused across a joint. Move that loop cut, or turn on its Cut through everything.
- Much of a part lies past its own cut: the part has taken over a neighbour’s surface, with no other warning to show for it — hair fused down the back can carry the torso’s back into the head, or a collar can carry the upper chest into an arm. The note names the part, how much of it lies past the cut, and the cut. Move that loop cut in Seams mode, or turn on its Cut through everything (for hair, at the neck).
- A part starts on another part’s surface: two markers are so close that their parts overlap. Check the markers.
- A side plane cut every curve on a part: ragged cloth joined the part’s front and back, so the plane couldn’t find a clean line between its loop cuts and cut everything it crossed. Move or roll that side plane.
- Extra seams were added so every island lies flat: for information; they are in
extra_seams. - An island could not be made to lie flat: the mesh is broken there. Run Clean first.
Editing in the viewport
Section titled “Editing in the viewport”While Character Seams is the selected node, the viewport has two modes. Switch between them with the Skeleton | Seams toggle at the top left, or press S.
Skeleton mode
Section titled “Skeleton mode”The markers, as in Auto Rig: the camera turns to the front view, and you drag each marker onto its spot. The skeleton and every cut follow the markers.
Seams mode
Section titled “Seams mode”The seams themselves, with the camera free to orbit:
- each loop cut is a dot on its bone and a see-through plane the size of the loop it cuts;
- each side plane is a long see-through panel along its part, from the part’s first to its last joint.
Click one to select it. Its gizmo has two modes:
- Slide (W): one arrow. It moves a cut along its bone, toward the next joint out or back toward the body, and a side plane along its normal (its offset, in cm).
- Tilt (E): rings. They tilt a cut’s plane, or roll a side plane about its bone (its roll).
You can also drag a cut or side plane itself: a cut slides along its bone, and a side plane moves along its normal. Reset puts the selected cut back at its joint, square to its bone, or the selected side plane back through the middle of its part, unrolled.
The seams cook again when you let go, and the side roll and offset rows in the parameters show the new values. A click without a drag moves nothing, and a drag on empty space orbits as usual. Cuts and side planes are stored against their bones, so when you move a marker later, each one moves with its bone.
Symmetry (on by default, X or the toolbar toggle) keeps the seams mirrored left to right: moving a left cut or side plane moves its right twin, and the neck cut and the head and torso side planes stay square to the middle of the body. Turning Symmetry on copies the left side onto the right, the markers included. Turn it off to edit each side on its own.
Undo (Ctrl+Z) steps back through seam edits and marker moves together, in the order you made them, whichever mode you are in.
Where to put it
Section titled “Where to put it”Put Character Seams after repair and reduction, before Auto Rig: for an AI character, Clean → Fill Holes → Polyreduce → Character Seams → Auto Unwrap (Seams: seams) → Bake → Auto Rig. It splits faces along the cuts, so it reshapes the mesh, and a rig on its input would be dropped. Give Auto Rig the same marker values so both nodes agree on the skeleton.
Faces are split exactly along the cuts: normals, UVs and colors carry onto the new points, and materials and existing groups carry onto the pieces.
Inputs
Section titled “Inputs”The character: upright, facing +Z, in an A- or T-pose, after repair and reduction.
Outputs
Section titled “Outputs”The same surface with faces split along the seams; edge groups `seams` (every cut) and `extra_seams` (cuts added so every island is a disc), and face groups head, torso, arm_l, arm_r, hand_l, hand_r, leg_l, leg_r, foot_l, foot_r.
Parameters
Section titled “Parameters”| Parameter | What it does | Default |
|---|---|---|
Neck position | Where the neck cut sits along its bone: 0 at the joint. | 0 |
Neck tilt A | How far the neck cut is tilted from square to its bone, about its first cross axis. | 0 |
Neck tilt B | How far the neck cut is tilted from square to its bone, about its second cross axis. | 0 |
Neck: cut through everything | Cut every loop the neck plane crosses, not only the ones around the bone. | Off |
Left shoulder position | Where the left shoulder cut sits along its bone: 0 at the joint. | 0 |
Left shoulder tilt A | How far the left shoulder cut is tilted from square to its bone, about its first cross axis. | 0 |
Left shoulder tilt B | How far the left shoulder cut is tilted from square to its bone, about its second cross axis. | 0 |
Left shoulder: cut through everything | Cut every loop the left shoulder plane crosses, not only the ones around the bone. | Off |
Right shoulder position | Where the right shoulder cut sits along its bone: 0 at the joint. | 0 |
Right shoulder tilt A | How far the right shoulder cut is tilted from square to its bone, about its first cross axis. | 0 |
Right shoulder tilt B | How far the right shoulder cut is tilted from square to its bone, about its second cross axis. | 0 |
Right shoulder: cut through everything | Cut every loop the right shoulder plane crosses, not only the ones around the bone. | Off |
Left wrist position | Where the left wrist cut sits along its bone: 0 at the joint. | 0 |
Left wrist tilt A | How far the left wrist cut is tilted from square to its bone, about its first cross axis. | 0 |
Left wrist tilt B | How far the left wrist cut is tilted from square to its bone, about its second cross axis. | 0 |
Left wrist: cut through everything | Cut every loop the left wrist plane crosses, not only the ones around the bone. | Off |
Right wrist position | Where the right wrist cut sits along its bone: 0 at the joint. | 0 |
Right wrist tilt A | How far the right wrist cut is tilted from square to its bone, about its first cross axis. | 0 |
Right wrist tilt B | How far the right wrist cut is tilted from square to its bone, about its second cross axis. | 0 |
Right wrist: cut through everything | Cut every loop the right wrist plane crosses, not only the ones around the bone. | Off |
Left hip position | Where the left hip cut sits along its bone: 0 at the joint. | 0 |
Left hip tilt A | How far the left hip cut is tilted from square to its bone, about its first cross axis. | 0 |
Left hip tilt B | How far the left hip cut is tilted from square to its bone, about its second cross axis. | 0 |
Left hip: cut through everything | Cut every loop the left hip plane crosses, not only the ones around the bone. | Off |
Right hip position | Where the right hip cut sits along its bone: 0 at the joint. | 0 |
Right hip tilt A | How far the right hip cut is tilted from square to its bone, about its first cross axis. | 0 |
Right hip tilt B | How far the right hip cut is tilted from square to its bone, about its second cross axis. | 0 |
Right hip: cut through everything | Cut every loop the right hip plane crosses, not only the ones around the bone. | Off |
Left ankle position | Where the left ankle cut sits along its bone: 0 at the joint. | 0 |
Left ankle tilt A | How far the left ankle cut is tilted from square to its bone, about its first cross axis. | 0 |
Left ankle tilt B | How far the left ankle cut is tilted from square to its bone, about its second cross axis. | 0 |
Left ankle: cut through everything | Cut every loop the left ankle plane crosses, not only the ones around the bone. | Off |
Right ankle position | Where the right ankle cut sits along its bone: 0 at the joint. | 0 |
Right ankle tilt A | How far the right ankle cut is tilted from square to its bone, about its first cross axis. | 0 |
Right ankle tilt B | How far the right ankle cut is tilted from square to its bone, about its second cross axis. | 0 |
Right ankle: cut through everything | Cut every loop the right ankle plane crosses, not only the ones around the bone. | Off |
Head side roll | Turns the head's side plane about its bone. 0 splits it front from back. | 0 |
Head side offset | Moves the head's side seam off the middle of its surface. | 0 cm |
Torso side roll | Turns the torso's side plane about its bone. 0 splits it front from back. | 0 |
Torso side offset | Moves the torso's side seam off the middle of its surface. | 0 cm |
Left arm side roll | Turns the left arm's side plane about its bone. 0 splits it front from back. | 0 |
Left arm side offset | Moves the left arm's side seam off the middle of its surface. | 0 cm |
Right arm side roll | Turns the right arm's side plane about its bone. 0 splits it front from back. | 0 |
Right arm side offset | Moves the right arm's side seam off the middle of its surface. | 0 cm |
Left hand side roll | Turns the left hand's side plane about its bone. 0 splits it palm from back. | 0 |
Left hand side offset | Moves the left hand's side seam off the middle of its surface. | 0 cm |
Right hand side roll | Turns the right hand's side plane about its bone. 0 splits it palm from back. | 0 |
Right hand side offset | Moves the right hand's side seam off the middle of its surface. | 0 cm |
Left leg side roll | Turns the left leg's side plane about its bone. 0 splits it front from back. | 0 |
Left leg side offset | Moves the left leg's side seam off the middle of its surface. | 0 cm |
Right leg side roll | Turns the right leg's side plane about its bone. 0 splits it front from back. | 0 |
Right leg side offset | Moves the right leg's side seam off the middle of its surface. | 0 cm |
Left foot side roll | Turns the left foot's side plane about its bone. 0 splits it sole from top. | 0 |
Left foot side offset | Moves the left foot's side seam off the middle of its surface. | 0 cm |
Right foot side roll | Turns the right foot's side plane about its bone. 0 splits it sole from top. | 0 |
Right foot side offset | Moves the right foot's side seam off the middle of its surface. | 0 cm |
Symmetry | Viewport editing only: keeps the markers, loop cuts and side planes mirrored left to right. The cook ignores it. | On |
Chin X | Where the tip of the chin is, left to right. | 0.5 |
Chin Y | Where the tip of the chin is, bottom to top. | 0.86 |
Neck base X | Where the base of the neck, between the collarbones, at shoulder height is, left to right. | 0.5 |
Neck base Y | Where the base of the neck, between the collarbones, at shoulder height is, bottom to top. | 0.8276 |
Groin X | Where the crotch, where the legs meet is, left to right. | 0.5 |
Groin Y | Where the crotch, where the legs meet is, bottom to top. | 0.5 |
Left wrist X | Where the character's left wrist (on the +X side) is, left to right. | 0.92 |
Left wrist Y | Where the character's left wrist (on the +X side) is, bottom to top. | 0.46 |
Right wrist X | Where the character's right wrist (on the −X side) is, left to right. | 0.08 |
Right wrist Y | Where the character's right wrist (on the −X side) is, bottom to top. | 0.46 |
Left elbow X | Where the character's left elbow is, left to right. | 0.81 |
Left elbow Y | Where the character's left elbow is, bottom to top. | 0.6 |
Right elbow X | Where the character's right elbow is, left to right. | 0.19 |
Right elbow Y | Where the character's right elbow is, bottom to top. | 0.6 |
Left knee X | Where the character's left knee is, left to right. | 0.61 |
Left knee Y | Where the character's left knee is, bottom to top. | 0.28 |
Right knee X | Where the character's right knee is, left to right. | 0.39 |
Right knee Y | Where the character's right knee is, bottom to top. | 0.28 |
See also
Section titled “See also”- Auto Rig: the same markers place the rig. Put Character Seams before it.