What a pin is
A pin is a single typed connector on a node - an input, on the node's input side, or an output, on its output side. Connections are always stored output to input: the graph auto-orients a new wire based on which end is the output and which is the input, so it does not matter which pin you actually drag from. Most input pins accept a single wire, and dropping a second one replaces the first, though a few are declared to accept more than one - see Nodes and Wires for the full wiring rules.
A pin's category is what decides whether it can be wired to another pin at all. Drag a wire out into empty space and the Add Node menu that opens is filtered to nodes with a compatible pin, with its header reading Compatible with {0} - see Working in the Graph.
Pin types
The table below covers every data type currently used by a pin in the library. Counts are pin totals across the whole node library in the current build, not a fixed catalogue - they rise as nodes are added.
Mesh and geometry
| Type | Pins | What it carries | Nodes that carry it |
|---|---|---|---|
| Mesh | 247 | A mesh: its vertices, triangles and their attributes. | Apply AI Mesh Data, Apply Animation Frame, Auto-Rig, Auto-Skin |
| Mesh List | 4 | An ordered list of meshes, for nodes that work across more than one at a time. | Create DNA, Generate LODs, Get Mesh Array Element, Mesh Array From Directory |
| Streaming Geometry Cache | 11 | A mesh that changes over time as a streamed cache, rather than a single static mesh. | Apply Deltas to Geometry Cache, Export Geometry Cache to Alembic, Export Geometry Cache to USD, Export to Geometry Cache |
| Deltas | 3 | A set of per-vertex offsets, such as a sculpt result, kept separately from a full mesh. | Apply Deltas (Topo Match), Get Deltas, Sculpt Mesh |
| Voxel Settings | 4 | The shared settings for a voxel operation. | Density To Mesh, Generate Settings, Paint, Sculpt Density |
| Transform | 3 | A position, rotation and scale. | Apply Rigid Transform, Find Plane, Rigid Fit |
Character types
| Type | Pins | What it carries | Nodes that carry it |
|---|---|---|---|
| DNA | 52 | A MetaHuman DNA definition - the rig, mesh and expression data read from or written to a .dna file. |
Bake DNA Geometry, Create DNA, Create DNA From Skeletal Mesh, DNA To Mesh |
| Animation | 11 | An animation clip. | Apply Animation Frame, Delta Mush Animation (Experimental), Load Animation (FBX), Load Animation Sequence |
| Bone Selection | 8 | A named selection of skeleton bones. | Fit Skeleton, Get DNA Expression, Get DNA RBF Pose, Paint Skin Weights |
| Landmarks | 17 | A set of named points on a mesh surface, used to align or fit it against another mesh. | Auto Face Landmarks, Invert Landmarks, Landmarks to RBF Points, Save Landmarks |
| RBF Points | 3 | The control points that drive an RBF (radial basis function) deformer. | Landmarks to RBF Points, RBF Deformer |
Maps, textures and assets
| Type | Pins | What it carries | Nodes that carry it |
|---|---|---|---|
| Weight Map | 36 | A per-vertex value spread across the mesh, such as a mask or a blend weight. | Blend, Delta Mush (Experimental), Fix Intersections, Get Attribute |
| Texture | 1 | An image. | Texture Sampler |
| Asset | 20 | A reference to an engine asset. | Body Pose Detection, Convert To Static Mesh, Create Material from Textures, Export to Texture Asset |
Asset pins mostly belong to the editor-only nodes described in the Introduction, which read or write Unreal Engine assets: an engine asset has nowhere to live in Studio, which has no project underneath it.
Plain value types
| Type | Pins | What it carries | Nodes that carry it |
|---|---|---|---|
| Number | 784 | A floating-point value. | Fix Intersections, Generate LODs, Guided Delta Mush, Remesh |
| Whole Number | 118 | An integer value. | Fix Intersections, Generate LODs, Guided Delta Mush, OpenSubdiv |
| Choice | 17 | One of a fixed set of named options - an enum. | Branch, Cellular Distance, Cellular Return, Compare Op |
| True/False | 2 | A boolean. | Mesh Health, Validate DNA |
| Text | 2 | A text value. | Generate LODs, List Morph Targets |
| Any | 2 | A wildcard that accepts any type. Reroute is the only node that uses it, so a wire can be split without narrowing what it carries. | Reroute |
Number covers what the schema internally calls float and double, and Whole Number covers int, int32 and int64 - those are implementation details, not labels you will see in the app itself.