How to Use Envelope Weights in Blender

Envelope weights in Blender provide a quick, volume-based method for skinning 3D models to armatures without the need for manual weight painting. By surrounding bones with adjustable control zones, envelope weights calculate vertex movement based on how close mesh vertices are to a bone's area of influence. This guide covers how to parent your mesh using envelope weights, adjust influence radiuses, and configure your bone settings for efficient rigging.

Step 1: Parent the Mesh with Envelope Weights

To start using envelope weights on a model:

  1. In Object Mode, select your 3D mesh.
  2. Hold Shift and select the armature (the armature must be selected last so it is the active object).
  3. Press Ctrl + P to open the Set Parent To menu.
  4. Choose With Envelope Weights.

This automatically assigns the vertices of your mesh to the nearest bone envelopes.

Step 2: Enable Envelope Viewport Display

To clearly see the size and reach of your bone envelopes:

  1. Select the armature.
  2. Go to the Armature Properties tab (the green running man icon) in the Properties panel.
  3. Expand the Viewport Display section.
  4. Change the Display As dropdown option from Octahedral to Envelope.

Your bones will now display as capsules with visible spherical handles at the joints and surrounding influence zones.

Step 3: Adjust the Envelope Radius and Distance

You can resize an envelope to control which parts of the mesh move with specific bones.

Resizing in the Viewport

  1. Select the armature and switch to Edit Mode or Pose Mode.
  2. Select the bone you want to adjust.
  3. Press Alt + S and move your mouse inward or outward to scale the envelope radius.
  4. Select individual bone heads or tails and press Alt + S to change the radius of specific joints.

Resizing in Bone Properties

  1. Select a bone and go to the Bone Properties tab (the green bone icon).
  2. Open the Deform section.
  3. Adjust the Envelope Distance slider to change how far the influence extends beyond the bone.
  4. Adjust the Head and Tail radius values for precise numerical control.

Step 4: Enable Envelope Binding in the Armature Modifier

For the mesh to deform using envelope weights during animation, ensure the Armature modifier is configured correctly:

  1. Select your mesh object and go to the Modifier Properties tab (the blue wrench icon).
  2. Locate the Armature modifier.
  3. Under the Bind To section, check the box for Bone Envelopes.
  4. If you want the mesh to rely entirely on envelopes rather than vertex groups, uncheck Vertex Groups.

Practical Tips for Envelope Weights

  • Combine with Vertex Groups: Envelope weights can act as a solid starting point. You can convert envelope weights to permanent vertex groups by selecting the mesh, going to Object Data Properties, and choosing Apply Envelope Weights from the Vertex Groups menu.
  • Low-Poly Models: Envelope weights work best on low-poly models, simple mechanical rigs, or stylized characters where complex muscle deformation is unnecessary.