Vertex Parenting In Blender: When And How To Use It
What is Vertex Parenting and When Should You Use It
Vertex parenting is a technique in Blender that allows you to deform one object, the “child”, by moving vertices on another object, the “parent”. It creates a relationship between the vertex groups of two objects.
The main use cases where vertex parenting is helpful are:
- Creating flexible appendages or extensions on a main body, like antennas, tentacles, or hair
- Making pieces of clothing or armor move realistically as an underlying body mesh deforms
- Simulating flesh and muscle movement by linking skin to underlying bones
Vertex parenting enables mesh parts to move independently of each other while maintaining overall spatial relationships. It generates more realistic and organic motions than just animating each object separately. The technique binds specific vertices on the child to areas of deformation on the parent, instead of coupling entire objects rigidly.
For example, you may vertex parent the tip of an antenna mesh to vertices on a head base mesh. As the head turns or bobs, the antenna tip moves in a proportional way, bending freely. The rest of the antenna mesh automatically deforms between the tip and base to create natural motion.
How to Set Up Vertex Parenting
The basic workflow for setting up vertex parenting is:
- Select the child mesh then shift select the parent mesh
- Tab into Edit mode on the child mesh
- Create vertex groups and assign child vertices to them
- Set up drivers to move child vertices based on parent vertices
To clarify, the “child” is the object being deformed and the “parent” contains the controlling vertices. For our antenna example, the antenna mesh is the child while the head base is the parent.
Selecting the Child and Parent Objects
First, select the child mesh object that you want to deform, like the antenna. While holding shift, also select the parent mesh object with the controlling vertices, like the head.
It’s important to select the child first before the parent. Having the child as the active object will streamline setting up vertex groups later.
Entering Edit Mode on the Child Object
With the child and parent objects selected, tab into Edit mode on the child object. You can confirm this by checking that the child mesh displays vertex dots while the parent mesh displays only an outline.
Edit mode allows you to select specific vertices on the child mesh to assign to vertex groups.
Selecting Vertex Groups
Next, you need to create vertex groups on the child object to correlate with areas of movement on the parent. This is done in the Object Data Properties panel while still in Edit mode.
For the antenna example, suitable vertex groups would be “antenna_tip”, “antenna_mid”, and “antenna_base”. Give descriptive names indicating which area of the child mesh will move.
Assigning Vertices to Groups
With empty vertex groups made, select child mesh vertices and use the Assign button to add them to respective groups.
For our antenna, add the tip vertices to the “antenna_tip” group, midsection vertices to “antenna_mid”, etc. The groups should contain vertices that logically move together when animated.
Controlling Child Objects with Vertex Groups
After setting up vertex groups, the next key step is using drivers and transformations to make the child vertices move based on manipulations to parent vertices.
Using Vertex Groups to Deform the Child
In Object mode, add a Transformation driver to the child object controlled by movements on relevant parent vertices. Enable Deform option.
For example, driving Z scale of “antenna_tip” group using Z coordinates of vertices in parent head tip. This makes the antenna curve as the head tilts.
Animating the Child by Moving Parent Vertices
Now transformations on parent vertices get propagated to connected child vertex groups with deformation. For the antenna, moving head tip vertices up/down directly animates antenna bending up/down.
This allows animating the flexible child indirectly through the parent, achieving simpler and more realistic motion.
Advanced Vertex Parenting Techniques
Skilled Blender artists utilize advanced techniques for enhanced vertex parenting effects:
Using Multiple Vertex Groups for Finer Control
Set up several vertex groups per child object for granular deformation. For example, group antenna vertices into lower, middle, and upper sections.
Animate each section separately using unique drivers for intricately bending motions. Allows independent control compared to driving one group.
Combining Vertex Parenting with Armatures and Bones
Blend vertex parenting with armatures. Skin upper arm vertices to shoulder/clavicle bones AND neighboring torso vertices for better deformation.
The vertex parenting adds mesh-driven movement on top of standard bone-based animation for ultra-realistic motion.
Troubleshooting Issues with Vertex Parenting
If unwanted distortion or breaks appear in the child mesh, refine vertex group selection and assignments. Closely consider deformation areas.
Reduce driver influence intensity if child moves excessively compared to parent. Fine-tune drivers to calibrate motion scale and range.
Example Tutorial on Creating a Flexible Character Antenna
Let’s walk through a hands-on example building an antenna that curves dynamically as the head turns.
Modeling the Antenna and Head Separately
First, build a simple head with block-out geometry, and model a tapered antenna as separate objects with origins centered.
Assigning Antenna Tip Vertices to Vertex Group
Tab into Edit mode on the antenna. Create a tip vertex group, and assign the end antenna vertices to it.
Moving Head to Animate Antenna
Finally, add a Transformation driver rotating and deforming the antenna tip group based on head tilt. Rotate the head to test!
