Rigging

Set Apose

After completing the modeling and texture work, import the WeightTransferMesh_APose prefab into the scene containing the finished model.

Confirm that both the position and rotation values of the created item and the WeightTransferMesh_APose prefab's transform are all set to 0.

In the hierarchy, right-click on the WeightTransferMesh_APose prefab and select Unpack Prefab to unpack it.

Then, rearrange the hierarchy structure as follows: choose a name for the item, and underneath it, paste the hips from the unpacked WeightTransferMesh_APose using Ctrl+C and Ctrl+V.

Alternatively, you can use the COPY and PASTE commands.

Let's hide the A POSE object and start rigging the hirts object.

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Start Rigging

Select the item object, then in the Rigging tab, drag and drop hips onto the root bone.

Then, click on Start Rigging.

Since the hips group cannot proceed with rigging directly using the existing bone data imported into Unity, this step is necessary to make UModeler X recognize it and place it into the Bone Tree.

Once rigging begins, a "Skinned Mesh Renderer" tab will appear below in the Inspector, indicating that the object has been rigged.

Select Bone

You can easily identify the position of bones by selecting their names in the Bone Tree and moving them in the Scene view.

Alternatively, you can enable the Enable Clicking on Bone option in the Tool Properties.

With this enabled, you can directly select bones in the Scene view while holding down the Shift key.

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Tools

Weights allow you to see the influence each selected vertex has from each bone, and you can easily adjust the weight of specific bones.

Weight

Select a vertex and then choose the desired bone.

Adjust the value by selecting a number or sliding the slider, then press "Apply Weight" to assign the weight value.

you can adjust the slider at the bottom to directly modify the weight value of the bone already connected.

Weight Brush

You can also use the weight brush to paint and adjust weight values.

Select the bone you want to adjust and paint with the brush.

If the weight brush type is set to Add, the values will increase; if set to Subtract, the values will decrease.

You can use Blur to smooth the values between vertices, making transitions more natural.

Reset Pose

During this process, the bone positions may change significantly from the original pose.

Since rigging should always be done with the original pose in mind, after the work is done, use the "Reset Poses" tool to reset the poses to their initial state.

Rebind Poses

The "Rebind Poses" tool is used when you want to change the bone positions during rigging.

After moving the bones, clicking "Rebind Poses" will move the vertices affected by the bone movement back to their original positions.

Weight Transfer

"Weight transfer" is a feature that copies weight values from an existing mesh.

Simply select the reference mesh and press "Transfer".

Weight Mirror

Weight Mirror is a feature that copies weight values from one side to the other.

When you have an object with different weights on each side, pressing Mirror will apply the same values to the opposite side.

Auto Weight

The Auto Weight tool automatically assigns weights to vertices based on their proximity to bones.

Adjust the weight width to set the range and then press "Apply Auto Weight".

Enveloping

Enveloping is a method of assigning weight values based on the size and position of an envelope capsule.

Select the desired bone, adjust the position and size of the envelope capsule, then apply the envelope. This applies the skinning values accordingly.

Edit Bone

The Edit Bones Tool is a tool that allows you to edit bones, including adding, deleting, separating, etc.

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Zepeto Item Rigging

Now, let's rig the actual ZEPETO item.

To streamline the process, use auto weight to perform the initial rigging.

Move the bones and check for any issues around the joints.

If there are any indentations or deformations at the joints, use the weight brush to correct them.

Select the bone you want to adjust and use the brush to modify the weight values, making the joint bends look natural.

Once you have finished adjusting, click reset poses to reset the bone positions.

Continue checking the other joints to ensure there are no issues.

After finishing one arm, use mirror weight to copy the weights to the other arm, ensuring both sides are identical.

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Swing Bone

In addition, there are cases where additional bones need to be added for secondary movement such as earrings, hair, or tails, which are not present in the existing animations. This is called the swing bone operation.

To perform swing bone operations, you need to add new bones.

Press "Edit Bones", select the closest bone to where you want to create the new bone, then enter the name and press "Add" to create the bone.

You don't need to add too many bones, just enough to avoid looking too stiff.

After adding the bones, proceed with the skinning operation.

The swing bone moves in accordance with the existing animation. This movement is based on the physics_drag_angle drag_restore drag values.

• drag determines how much the bone moves. Lower values result in more movement, while higher values make it stiffer. The optimal range is typically between 7 to 17.
• angle drag controls the rotation angle of the joint. Lower values result in larger swings, while higher values produce smaller swings. The suitable range is generally between 10 to 25.
• restore drag determines the strength of returning to the initial position. Lower values lead to slower returns, giving a water-like feeling, whereas higher values result in faster returns. The recommended range is typically between 15 to 30.

You can assign these values only to the topmost swing bone, or if you want different values for each swing bone, you can append physics_drag_angle drag_restore drag after each swing bone name.

After rigging is completed, press Reset Pose to reset the pose to its initial state.

For more details, please check the link below.