Introducting Fusion For Blender

Non-Destructive Live Mesh Fusing for Blender 5.0+

Extension By Egret

Fusion lets you merge meshes the way metaballs blend together, but with real geometry. Create smooth, organic transitions between objects while keeping everything fully live and reversible until you're ready to apply the result.

Whether you're building creatures, kitbashing hard-surface assets, or exploring forms, Fusion gives you a fast, flexible workflow without committing to destructive operations.

Requirements

Blender 5.0+ or newer
Compatible with Cycles, Eevee, and Material Preview

Installation

Open Edit → Preferences → Get Extensions
Click the dropdown menu in the top-right corner and select Install from Disk
Choose fusion-1.0.0.zip

After installation, you'll find the Fusion panel in the 3D Viewport Sidebar (N key).

Quick Start

Position two meshes so they intersect.
Select both objects, making the destination object the active (last selected) object.
Press Ctrl + Shift + M or click Fuse in the Fusion panel.

Fusion creates a single mesh with genuinely merged topology and a smooth metaball-style transition where the objects meet.

The original meshes remain available as live wireframe guides. Move, rotate, or scale them and the fusion updates automatically. Use Unfuse at any time to restore the original objects exactly as they were.

Workflow

Fuse

Select the mesh you want to fuse and the destination surface, then click Fuse.

If the objects do not overlap, Fusion will notify you. Simply reposition one of the guides until an intersection exists.

Live Editing

Original source objects remain in the scene as editable wireframe guides.

While the fusion is live you can:

Move guides
Rotate guides
Scale guides
Continuously reshape the fusion result

The fused mesh itself is intentionally transform-locked during live mode. The source guides act as the control handles.

Additional options:

Live

Disables automatic rebuilding while you position heavy meshes. Rebuild manually when ready.

Show Guides

Hide or reveal the wireframe source objects.

Select Fused Result

Quickly jump back to the generated fusion object.

Unfuse

Removes the fused result and restores the original meshes.

Fusion preserves:

Collections
Shading
Visibility settings
Object data

Your source objects are never modified.

Use Unfuse All from Blender's Operator Search to revert every Fusion setup in the file.

Apply

When you're satisfied with the result, open the Output section.

Apply Fusion

Converts the live fusion into a standard Blender mesh.

Applies modifiers
Unlocks transforms
Centers the origin

Apply for Cycles

Performs a standard apply and automatically adds a Bevel shader setup to improve Cycles indirect lighting around fusion boundaries.

Keep Sources

Stores original meshes inside a hidden Fusion_Backup collection instead of deleting them.

Shape Controls

Fuse Amount

Master control that drives Tension, Spread, and Shading together.

Once an individual parameter is adjusted, the master control becomes inactive until reset.

Tension

Controls how strongly the transition relaxes into clean, evenly flowing topology.

Spread

Determines how far the blend extends from the contact region.

Bulge

The primary metaball control.

1.0 = mathematically accurate smooth union
Higher values increase swelling
Negative values create a pinched transition

Flow

Biases the blend toward one side.

Positive values spread across the destination surface
Negative values hug the fused object

Inflate

Expands or contracts the transition area along surface normals.

Grain

Adds organic noise across the blend region.

Ideal for creature work, sculpting workflows, and natural forms.

Shading

Controls the width of the smooth shading zone.

Profile

Choose the blend shape:

Soft — Organic easing
Even — Linear transition
Crisp — Tight fillet
Bell — Rounded metaball-style swell

Topology Controls

Surface Mode

Preserves the original topology everywhere except the contact area.

Features:

UV preservation
Material preservation
Localized topology modifications

Voxel Mode

Rebuilds the entire result as clean all-quad geometry.

Features:

Organic silhouettes
Uniform topology
Metaball-like results

Voxel Detail controls the remesh resolution.

Note: UVs and material assignments are rebuilt in Voxel mode.

Precision

Controls solver quality.

Draft — Fastest performance
Balanced — Recommended for everyday use
High — Maximum quality

Surface Mode Options

Quad Fill

Converts seam-generated triangles and n-gons into quads.

Weld

Controls cleanup of tiny edges before quad reconstruction.

Carve Interior

Removes hidden interior geometry where meshes overlap.

Disable this option if you need to retain internal shells.

Refine Seam

Adds additional geometry around the contact region before blending.

Cuts

Controls subdivision density.

Even Cuts

Works reliably on any mesh.

Curved

Follows existing surface curvature and works best with reasonable topology density.

Mirror

Enable live mirroring across:

X Axis
Y Axis
Z Axis

Mirroring remains fully live and is automatically applied when the fusion is finalized.

Shortcuts

ShortcutActionCtrl + Shift + MFuse selected meshesCtrl + Shift + BFuse all selected meshes onto the active object

Batch Fusing

Select multiple source objects and one active destination object, then press Ctrl + Shift + B.

Fusion creates a chained result while displaying progress feedback.

Each fusion can still be unfused independently.

Additional Features

FU_MergeGroup

Every fusion generates a vertex group containing blend weights.

Useful for:

Masks
Textures
Geometry effects
Modifier workflows

Scale Guard

Detects unapplied object scale and provides a one-click fix to prevent incorrect blend widths.

Modifier Support

Source modifiers are evaluated automatically during fusion.

Original objects retain their modifier stacks for future unfusing.

Tips

Organic Metaball Style

Bulge: 1.0
Profile: Bell
Larger Spread values

Hard Surface Assembly

Bulge: 0
Profile: Crisp
Small Spread values
Refine Seam enabled

Heavy Sculpt Meshes

Precision: Draft
Live disabled while positioning
Rebuild manually
Switch to High before applying

Perfect Quad Topology

Use Voxel mode for guaranteed all-quad output.

Important Notes

Material Blending

Fusion merges geometry only.

Material assignments are preserved in Surface mode, but Fusion does not blend textures or generate material transition zones.

Game Assets

Applied meshes are optimized for modeling workflows rather than game-ready topology. Additional retopology may be required for real-time applications.

Glass & Refraction

Highly refractive materials at fusion boundaries are not officially supported in version 1.0.

Batch Chains

Long fusion chains rebuild live one level deep. Earlier links may require manual rebuilding of later links after major changes.

Troubleshooting

Objects Do Not Intersect

Ensure the meshes overlap. Fusion requires actual intersection geometry.

Thin Triangles Along the Seam

Try one of the following:

Increase Weld
Enable Refine Seam
Switch to Voxel Mode

Slow Viewport Performance

Disable Live updates
Use manual rebuilds
Switch Precision to Draft

Fused Object Cannot Be Moved

This is expected behavior while Fusion remains live.

Move the wireframe guides instead, or use Apply Fusion to convert the result into a standard mesh.

Support

Found a bug or have a feature request?

Please contact us through the Superhive product page and include:

Blender version
Steps to reproduce the issue
Error messages from Window → Toggle System Console (if available)

We actively maintain Fusion and typically address reported issues quickly.