The Geometry Script Library contains a very broad range of functionality, from low-level mesh construction and queries, such as building a mesh triangle-by-triangle or counting its vertices, to high-level operations like mesh booleans and intersection tests.
For more information on using the Geometry Script Library, see Geometry Script Users Guide.
Most functions are available while working in the editor and at runtime. However, some are only available while working in the editor and have been noted in the tables below.
Asset and Component Read/Write
You can use these functions to read and write Dynamic Mesh instances, such as reading and writing to or from an existing or new Asset or Component.
| Node Name | Description |
|---|---|
| Copy Mesh From Static Mesh | Extracts a Dynamic Mesh from a Static Mesh Asset. |
| Copy Mesh To Static Mesh | Updates a Static Mesh Asset with new geometry converted from a Dynamic Mesh. |
| Copy Mesh From Component | Extracts a Dynamic Mesh Actor from any supported Component type, in World or Local space. |
| Create New Volume From Mesh | Creates a new Volume Actor, such as a Blocking Volume, from a Dynamic Mesh Actor. This node only works in the Editor. |
| Create New Static Mesh Asset From Mesh | Creates a new Static Mesh Asset from a Dynamic Mesh Actor. This node only works in the Editor. |
| Set Static Mesh Collision From Mesh | Generates Simple Collision shapes for a Static Mesh Asset based on the input Mesh. |
| Set Dynamic Mesh Collision From Mesh | Generate Simple Collision shapes for a Dynamic Mesh Component based on the input Mesh. |
| Copy Collision Meshes From Object | Extracts the Collision Geometry from From Object and copies it with meshes stored in To Dynamic Mesh.
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| Reset Dynamic Mesh Collision | Clears Simple Collisions from the Dynamic Mesh Component. |
| Copy Mesh From Skeletal Mesh | Copies the Skeletal Mesh into the target Dynamic Mesh. |
| Copy Mesh To Skeletal Mesh | Copies the given Dynamic Mesh to the Skeletal Mesh. |
Primitive Generation
You can use these functions to generate and append a primitive mesh to the input Dynamic Mesh.
| Node Name | Description |
|---|---|
| Append Box | Appends a 3D box to a specified Dynamic Mesh. |
| Append Sphere Lat Long | Appends a 3D Sphere triangulated using latitude/longitude topology to a Dynamic Mesh. |
| Append Sphere Box | Appends a 3D sphere triangulated using box topology to a Dynamic Mesh. |
| Append Capsule | Appends a 3D Capsule to a Dynamic Mesh. |
| Append Cylinder | Appends a 3D Cylinder (with optional end caps) to a Dynamic Mesh. |
| Append Cone | Appends a 3D cone to a Dynamic Mesh. |
| Append Torus | Appends a 3D torus (donut) or partial torus to a Dynamic Mesh. |
| Append Rectangle | Appends a planar Rectangle to a Dynamic Mesh. |
| Append Round Rectangle | Appends a planar Rectangle with Rounded Corners (RoundRect) to a Dynamic Mesh. |
| Append Disc | Appends a planar disc to a Dynamic Mesh. |
| Append Triangulated Polygon | Appends a Delaunay triangulation of a planar 2D polygon to a Dynamic Mesh. |
| Append Revolve Polygon | Appends the surface-of-revolution of a 2D polygon, full or optionally-capped partial revolution to a Dynamic Mesh. |
| Append Spiral Revolve Polygon | Revolves a 2D polygon on a helical path, like one used to create a vertical spiral. |
| Append Revolve Path | Revolves an open 2D path, with optional top and bottom end caps. |
| Append Simple Extrude Polygon | Extrudes a 2D polygon along a vertical path using a selected Dynamic Mesh. |
| Append Simple Swept Polygon | Sweeps a 2D polygon along an arbitrary 3D path using a selected Dynamic Mesh. |
| Append Linear Stairs | Appends a linear staircase using a selected Dynamic Mesh. |
| Append Curved Stairs | Appends a rising circular staircase using a selected Dynamic Mesh. |
| Append Mesh Transformed | Applies each transform to Append Mesh and then adds its geometry to the Target Mesh. |
| Append Sweep Polygon | Sweeps and rotates a 2D polygon along the Sweep Path to create a 3D mesh that appends to the provided mesh. |
| Append Voronoi Diagram 2D | Generates triangulated Voronoi Cells from the provided Voronoi Sites, identifying each with PolyGroups, and appends to the provided mesh. |
Transform and Deformation
You can use these functions to manipulate the vertex positions of a Dynamic Mesh. These manipulations do not change the mesh topology or connectivity.
| Node Name | Description |
|---|---|
| Translate Mesh | Applies a translation to the vertices of a Mesh. |
| Scale Mesh | Applies a scale transformation to the vertices of a Mesh. |
| Transform Mesh | Applies an arbitrary FTransform to the vertices of a Mesh. |
| Apply Bend Warp To Mesh | Applies a bend warp around an axis defined by a Transform. |
| Apply Twist Warp To Mesh | Applies a twist warp around an axis defined by a Transform. |
| Apply Flare Warp To Mesh | Applies a Flare/Bulge warp. |
| Apply Math Warp To Mesh | Applies various simple math-function-based warps, currently a 1D or 2D sine-wave with arbitrary orientation. |
| Apply Perlin Noise To Mesh | Applies a 3D Perlin noise displacement to the entire mesh or regions of the mesh defined by optional Selection. |
| Apply Iterative Smoothing To Mesh | Applies several mesh smoothing iterations to the entire mesh or a subset defined by the optional Selection |
| Apply Displace From Texture Map | Applies a displacement to a Dynamic Mesh based on a Texture2D and a UV channel. |
| Rotate Mesh | Rotates the mesh relative to the specified origin. |
Composition and Decomposition
You can use these functions to combine meshes together, or split them apart.
| Node Name | Description |
|---|---|
| Copy Mesh To Mesh | Copies the mesh from one Dynamic Mesh into another. |
| Get Sub Mesh From Mesh | Copies a list of triangles from one Dynamic Mesh to another. |
| Split Mesh By Components | Separates a mesh into parts, one for each connected component, drawn from a Dynamic MeshPool. |
| Split Mesh By Material IDs | Separates a mesh into parts, one for each Material ID, drawn from a Dynamic MeshPool. |
| Append Mesh | Appends the geometry from one mesh to another, with optional Transform. |
| Append Mesh Repeated | Appends the geometry from one mesh to another based on the number of times it should repeat, accumulating a transform each time. This operation is useful for making patterns. |
Mesh Modeling
These functions provide standard high-level modeling operations, but are generally calling the low-level mesh processing code that the similarly-named Tool in Modeling Mode would call.
| Node Name | Description |
|---|---|
| Apply Mesh Boolean | Applies a Boolean operation (such as, Union, Intersect, and Subtract) to a Dynamic Mesh based on a second mesh. |
| Apply Mesh Plane Cut | Applies a plane cut to a mesh, optionally filling any holes created. |
| Apply Mesh Plane Slice | Slices a mesh into two halves, with optional hole filling. |
| Apply Mesh Mirror | Mirrors a mesh across a plane, with optional cutting and welding of triangles. |
| Apply Mesh Offset | Moves the vertices of a mesh to an offset surface. |
| Apply Mesh Shell | Moves a copy of the mesh's triangles to an offset surface, and stitches them to the original triangles. For example, to create a thickened shell. |
| Apply Mesh Extrude | Extrudes the triangles of a mesh along a constant direction. For example, it creates a solid from an open triangulated polygon. |
| Apply Mesh Solidify | Replaces the mesh with a voxelized-and-meshed approximation (VoxWrap operation). |
| Apply Mesh Morphology | Replaces the mesh with an SDF-based offset mesh approximation. |
| Apply Mesh Self Union | An object performs a Boolean Union operation with itself, computing actions such as repairing self-intersections and removing floating geometry. |
| Apply Mesh Polygroup Bevel | Applies Mesh Bevel operation to all Polygroup Edges. |
Mesh Selections
These functions identify regions of a mesh to different tools so they can operate locally. Several functions can work on the entire mesh or a subset defined by a Selection. Selection Types include: Triangle, Vertices, and PolyGroups.
| Node Name | Description |
|---|---|
| Invert Mesh Selection | Invert the Selection on the Target Mesh. |
| Create Select All Mesh Selection | Creates a Selection of the given Selection Type containing all the elements of the Target Mesh |
| Convert Mesh Selection | Converts a Mesh Selection to a different Type. By default, Vertices map to Triangles within a one-ring neighborhood and Triangles to all contained vertices. |
| Combine Mesh Selections | Combines two Mesh Selections into a new Mesh Selection. The two inputs, Selection A and Selection B must have the same Type. |
| Convert Index Array To Mesh Selection | Creates a Mesh Selection from the Index Array. |
| Convert Index Set To Mesh Selection | Creates a Mesh Selection from the Index Set. |
| Convert Mesh Selection To Index Array | Converts a Mesh Selection to an Index Array. |
| Convert Index List To Mesh Selection | Creates a Mesh Selection from the Index List. For cases where the Index List Type does not match the Selection Type, Convert Mesh Selection with bAllowPartialInclusion=true is used to convert. |
| Convert Mesh Selection To Index List | Converts a Mesh Selection to an Index List. |
| Select Mesh Elements In Box | Creates a new Mesh Selection of the Selection Type for the Target Mesh by finding all elements contained in the Box. |
| Select Mesh Elements In Sphere | Creates a new Mesh Selection of the Selection Type for the Target Mesh by finding all elements contained in the Sphere. |
| Select Mesh Elements With Plane | Creates a new Mesh Selection of the Selection Type for the Target Mesh by finding all elements on one side of the plane, particularly the side that the surface normal of a Plane points towards. |
| Select Mesh Elements By Normal Angle | Creates a new Mesh Selection of the Selection Type for the Target Mesh by finding all elements that have a normal vector that is within an angular deviation threshold from the given Normal. For Triangle and Polygroup selections the triangle facet normal is used, for Vertex selections the per-vertex averaged normal is used. |
| Select Mesh Elements Inside Mesh | Creates a new Mesh Selection of the Selection Type for the Target Mesh by finding all elements inside a second Selection Mesh. |
| Expand Mesh Selection To Connected | Expands the Selection on the Target Mesh to connected regions and returns the New Selection. |
| Get Mesh Selection Bounding Box | Gets the 3D Bounding Box of a Mesh Selection. |
| Get Mesh Selection Boundary Loops | Computes the set of Vertex Loops bordering a Mesh Selection. Both the 3D polylines and lists of vertex indices are returned for each Loop. For a Vertex selection, this function returns the border loops around the one-ring neighborhood of the vertex selection. |
| Get Mesh Selection Info | Queries information about a Mesh Selection. |
| Debug Print Mesh Selection | Prints information about the Mesh Selection to the Output Log. |
Modify Mesh by Selection
Functions for editing geometry from a given selection.
Transform Mesh
| Node Name | Description |
|---|---|
| Transform Mesh Selection | Applies the given transform to the selected part of the mesh. |
| Translate Mesh Selection | Applies the given translation to the selected part of the mesh. |
| Rotate Mesh Selection | Rotates the selected part of the mesh relative to the specified origin. |
| Scale Mesh Selection | Applies the given scale to the selection part of the mesh. |
Materials and PolyGroups
| Node Name | Description |
|---|---|
| Set Material ID For Mesh Selection | Sets a new Material ID on all the triangles of the given Selection. |
| Set Polygroup For Mesh Selection | Set a new Polygroup on all the triangles of the given Selection, for the given Group Layer. |
Mesh Modeling
| Node Name | Description |
|---|---|
| Apply Mesh Disconnect Faces | Disconnects the triangles of the Target Mesh identified by the Selection. |
| Apply Mesh Duplicate Faces | Duplicates the triangles of Target Mesh identified by the Selection input. |
| Apply Mesh Linear Extrude Faces | Applies Linear Extrusion to the triangles of Target Mesh identified by the Selection. |
| Apply Mesh Offset Faces | Applies an Offset to the faces of Target Mesh identified by the Selection, or all faces if the Selection is empty. |
| Apply Mesh Inset Outset Faces | Applies an Inset or Outset to the faces of Target Mesh identified by the Selection, or all faces if the Selection is empty. |
| Apply Mesh Bevel Selection | Applies a Mesh Bevel operation to parts of Target Mesh using the Bevel Options settings. |
Subdivision Functions
These functions apply various mesh subdivision strategies to a Dynamic Mesh.
| Node Name | Description |
|---|---|
| Apply Polygroup Catmull Clark SubD | Apply Catmull Clark Subdivision to the Polygroup Topology of the Mesh (discards input triangulation). This node only works in the Editor. |
| Apply Triangle Loop SubD | Apply Loop Subdivision to the input mesh. This node only works in the Editor. |
| Apply Selective Tessellation | Tessellate the specified mesh Selection using the indicated Pattern Type. |
| Apply PNTesselation | Applies PN Tessellation to the input mesh. |
| Apply Uniform Tessellation | Applies uniform tessellation to the input mesh. |
Simplification Functions
These functions simplify a mesh using various strategies.
| Node Name | Description |
|---|---|
| Apply Simplify To Triangle Count | Simplifies the mesh until a target triangle count is reached. |
| Apply Simplify To Vertex Count | Simplifies the mesh until a target vertex count is reached. |
| Apply Simplify To Tolerance | Simplifies the mesh to a target geometric tolerance. For example, any further simplification would result in a deviation from the input mesh larger than the tolerance. |
| Apply Simplify To Planar | Simplifies planar areas of the mesh that have more triangles than necessary. This does not change the 3D shape of the mesh. |
| Apply Simplify To Polygroup Topology | Simplifies the mesh down to the Polygroup Topology. For example, the high-level faces of the mesh polygroups. Another example would be on a default Box-Sphere where simplifying to polygroup topology produces a box. |
Normals Functions
These functions recompute the Normals of a mesh.
| Node Name | Description |
|---|---|
| Flip Normals | Flips the mesh normals by reversing the orientation of each face. |
| Set Per Vertex Normals | Sets the mesh normals to per-vertex normals. For example, no split normals at any vertex. |
| Set Per Face Normals | Sets the mesh normals to per-face/triangle normals. For example, split normals along every edge of the mesh. |
| Compute Split Normals | Computes split-normals for the mesh based on an angle tolerance and/or other factors such as polygroup topology. |
| Recompute Normals | Recomputes the existing mesh normals. Preserves existing split normals. For use after mesh deformations, for example. |
| Compute Tangents | Recomputes tangents for the mesh (various methods). |
Cleanup/Repair Functions
You can use these functions to fix issues in a mesh, or to apply other standard repairs.
| Node Name | Description |
|---|---|
| Compact Mesh | Compacts the mesh's vertices and triangles to remove any "holes" in the Vertex ID or Triangle ID lists (see discussion in Low-Level Mesh Queries section). |
| Discard Mesh Attributes | Removes the Attribute Set from a Dynamic Mesh, such as all UVs, Normals, Material IDs, Vertex Colors, and extended Polygroup Layers. Note that this may prevent many functions from working. |
| Auto Repair Normals | This function tries to automatically reorient the Normals of a mesh so that they are consistent, such as fixing flipped normals. |
| Weld Mesh Edges | Welds any open boundary edges of the mesh together if possible in order to remove "cracks." |
| Fill All Mesh Holes | Tries to fill all open boundary loops (such as holes in the geometry surface) of a mesh. |
| Remove Small Components | Removes connected components of the mesh that have a volume, area, or triangle count below a threshold. |
| Remove Hidden Triangles | Removes any triangles in the mesh that are not visible from the exterior view, under various definitions of "visible" and "outside." |
| Resolve Mesh TJunctions | Attempts to resolve t-junction in the Target Mesh. |
| Split Mesh Bowties | Splits vertices in the Target Mesh that otherwise produce a bowtie where only a single vertex connects regions of the mesh. |
| Repair Mesh Degenerate Geometry | Modifies the Target Mesh by deleting small triangles or merging triangles until all edges are greater than a specified minimum length. |
Low-Level Mesh Queries
These functions provide low-level information about the elements of a mesh. In this context, VertexID and TriangleID are integers.
In a Dynamic Mesh, there may be gaps in VertexID or TriangleID range — after vertices/triangles are deleted — and some operations (like Simplification) may return a mesh with gaps present. Gaps in the ID ranges are cleaned up using the Compact Mesh function.
| Node Name | Description |
|---|---|
| Get Vertex Count | Gets the number of vertices in the mesh. |
| Get Num Vertex IDs | Gets the number of Vertex IDs in the mesh, which may be larger than the Vertex Count, if the mesh is not dense. For example, after deleting vertices. |
| Is Valid Vertex ID | Returns true if a Vertex ID refers to a valid vertex. |
| Get All Vertex IDs | Returns an IndexList of all Vertex IDs in mesh. |
| Get Vertex Position | Gets the 3D position of a mesh vertex, by Vertex ID. |
| Get All Vertex Positions | Returns a Vector List of all the mesh vertex positions. This list may be extensive. |
| Get Triangle Count | Returns the number of triangles in the mesh. Note that this is a function on the Dynamic Mesh directly. |
| Get Num Triangle IDs | Gets the number of Triangle IDs in the mesh. The number may be larger than the Triangle Count if the mesh is not dense, even after deleting triangles. |
| Is Valid Triangle ID | Returns true if a TriangleID refers to a valid Triangle. |
| Get All Triangle IDs | Returns an Index List of all Triangle IDs in a mesh. |
| Get Triangle Indices | Returns the vertex indices triplet for a Triangle. |
| Get All Triangle Indices | Returns a TriangleList of all Triangle indices triplets in a mesh. |
| Get TrianglePositions | Returns the three corner positions for a Triangle. |
| Get TriangleFace Normal | Returns the face/facet normal of a Triangle. |
| Get TriangleUVs | Returns the three corner UVs for a Triangle. |
| Get Triangle Material ID | Returns the current Material ID for a Triangle. |
| Get All Triangle Material IDs | Returns an Index List of all triangle Material IDs. |
| Get Triangle Polygroup ID | Returns the current Polygroup ID for a Triangle, in a given Polygroup layer. |
| Get Has Vertex ID Gaps | Returns true if there are gaps in the Vertex ID list. For example, Get Number of Vertex IDs is greater than Get Vertex Count. |
| Get Has Triangle ID Gaps | Returns true if there are gaps in the Triangle ID list, such that Get Num Triangle IDs is greater than Get Triangle Count. |
| Get Is Dense Mesh | Returns true if the mesh is dense. For example, no gaps in Vertex IDs or Triangle IDs. |
| Get Mesh Has Attribute Set | Returns true if the mesh has an Attribute Set enabled to store UVs, Normals, Material IDs, and Vertex Colors. This is generally enabled by default.. |
Low-Level Mesh Building
These functions construct a mesh triangle-by-triangle and perform other low-level mesh editing operations.
Using these functions in situations that involve looping over the elements of meshes with many thousands of triangles can be quite slow in Blueprint or Python scripting.
| Node Name | Description |
|---|---|
| Set Vertex Position | Sets the 3D position of a mesh vertex. |
| Add Vertex To Mesh | Adds a new vertex to the mesh and returns a new Vertex ID. |
| Add Vertices To Mesh | Adds a list of vertices to the mesh. |
| Delete Vertex From Mesh | Removes a vertex from the mesh. |
| Delete Vertices From Mesh | Removes a list of vertices from the mesh. |
| Add Triangle To Mesh | Adds a triangle (3-element Vertex ID tuple) to the mesh. |
| Add Triangles To Mesh | Adds a list of triangles to the mesh. |
| Delete Triangle From Mesh | Removes a triangle from the mesh. |
| Delete Triangles From Mesh | Removes a list of triangles from the mesh. |
| Delete Triangles In Polygroup | Deletes all triangles from the mesh that have a particular polygroup, in a specific Polygroup layer. |
| Append Buffers To Mesh | Adds a set of vertices/triangles to the mesh, with attributes such as Normals and UVs. Similar to Create Mesh Section in Proc Mesh Component. |
| Set Mesh Triangle Normals | Sets the Normals of a mesh triangle. |
| Set Mesh Triangle UVs | Sets the UVs of a mesh triangle. |
| Set Triangle Material ID | Sets the Material ID of a mesh triangle. |
Low-Level List Management
These functions cover list management for: Index List, Scalar List, Vector List, UV List, and Color List.
| Node Name | Description |
|---|---|
| Get Index List Length | Returns the number of items in the Index List. |
| Get Index List Last Index | Returns the index of the last item in the Index List. |
| Get Index List Item | Returns the item stored in the Index List at the specified location. |
| Set Index List Item | Updates the value of the item stored in the Index List at the specified location. |
| Convert Index List To Array | Converts an Index List to an array of integers. |
| Convert Array To Index List | Converts an array of integers to an Index List. |
| Duplicate Index List | Duplicates the contents Index List into Duplicate List. |
| Clear Index List | Resets all the items in the Index List to the Clear Value. |
| Get Scalar List Length | Returns the number of items in the Scalar List. |
| Get Scalar List Last Index | Returns the index of the last item in the Scalar List. |
| Get Scalar List Item | Returns the Scalar (double) stored in the Scalar List at the specified location. |
| Set Scalar List Item | Updates the value of the Scalar stored in the Scalar List at the specified location. |
| Convert Scalar List To Array | Converts a Scalar List to an array of doubles. |
| Convert Array To Scalar List | Converts an array of doubles to a Scalar List. |
| Duplicate Scalar List | Copies the contents of Scalar List into Duplicate List. |
| Clear Scalar List | Reset all the items in the Scalar List to the Clear Value. |
| Get Vector List Length | Returns the number of items in the Vector List. |
| Get Vector List Last Index | Return the index of the last item in the Vector List. |
| Get Vector List Item | Return the FVector stored in the VectorList at the specified location. |
| Set Vector List Item | Updates the value of the FVector stored in the Vector List at the specified location. |
| Convert Vector List To Array | Converts a Vector List to an array of FVectors. |
| Convert Array To Vector List | Converts an Array of FVectors to a Vector List. |
| Duplicate Vector List | Copies the contents of Vector List into Duplicate Vector List. |
| Clear Vector List | Resets all the items in the Vector List to the Clear Value. |
| Get UV List Length | Returns the number of items in the UV List. |
| Get UV List Last Index | Returns the index of the last item in the UV List. |
| Get UV List Item | Returns the FVector2D stored in the UV List at the specified location. |
| Set UV List Item | Updates the value of the FVector2D stored in the UV List at the specified location. |
| Convert UV List To Array | Converts a UV List to an array of FVector2Ds. |
| Convert Array To UV List | Converts an array of FVector2D to UVList. |
| Duplicate UV List | Duplicates the contents of UV List into Duplicate List. |
| Get Color List Length | Returns the number of items in the Color List. |
| Get Color List Last Index | Returns the index of the last item in the Color List. |
| Get Color List Item | Returns the FLinearColor stored in the Color List at the specified location. |
| Set Color List Item | Updates the value of the FLinearColor stored in the Color List at the specified location. |
| Convert Color List To Array | Converts the Color List to an array of FLinearColor. |
| Convert Array To Color List | Converts an array of FLinearColor to a Color List. |
| Extract Color List Channel | Creates a Scalar List that corresponds to the 0,1, or 2 channel of a Color List. |
| Extract Color List Channels | Creates a Vector List from a Color List. The channels in the Color List are mapped to vector components by means of X Channel Index, Y Channel Index, and Z Channel Index. |
Low-Level Math
Functions that operate on the Vector Lists and Scalar Lists in a component wise fashion. The functions that take multiple lists, such as Vector Dot, require the lists to have the same number of elements.
| Node Name | Description |
|---|---|
| Vector Length | Computes the length of each vector in Vector List A and returns the value in the Scalar List. |
| Vector Dot | Computes the dot-product between each pair of vectors in Vector List A and Vector List B, and returns the value in the new Scalar List. |
| Vector Cross | Computes the cross-product between each pair of vectors in Vector List A and Vector List B and returns the value in the new Vector List. |
| Vector Normalize In Place | Normalizes each vector in Vector List, and stores the value in a Vector List. If a vector is degenerate, set the normal to the Set On Failure vector. |
| Vector Blend | Computes ConstantA * A + ConstantB * B for each pair of vectors in Vector List A and Vector List B, and returns the value in the new Vector List. By default this (constants = 1) adds the two vectors. Set You can also use the function to Linear Interpolate, by setting |
| Vector Blend In Place | Computes ConstantA * A + Constant B * B for each pair of vectors in Vector List A and Vector List B, and stores the value in Vector List B. By default this (constants = 1) adds the two vectors. Set You can also use the function to Linear Interpolate, by setting |
| Scalar Vector Multiply | Computes Scalar Multiplier * Scalar * Vector for each scalar/vector pair in the two input lists, and returns the value in a new Vector List. |
| Scalar Vector Multiply In Place | Computes Scalar Multiplier * Scalar * Vector for each scalar/vector pair in the two input lists, and stores the value in the input Vector List. |
| Constant Vector Multiply | Computes Constant * Vector for each element in the Vector List and returns the value in a new list. |
| Constant Vector Multiply In Place | Computes Constant * Vector for each element in Vector List, and stores the value in Vector List. |
| Vector To Scalar | Converts each Vector in Vector List to a Scalar by computing ConstantX * Vector.X + ConstantY * Vector.Y + ConstantZ * Vector.Z , and returns the value in a new Scalar List. You can use it to extract the X, Y, and Z values from a Vector, or other component-wise math. |
| Scalar Invert | Computes Numerator / Scalar for each element of the Scalar List and returns the value in a new Scalar List. If Abs(Scalar) < Epsilon, set to Set On Failure value. |
| Scalar Invert In Place | Computes Numerator / Scalar for each element of the Scalar List and stores the value in input Scalar List. If Abs(Scalar) < Epsilon, set to Set On Failure value. |
| Scalar Blend | Computes ConstantA * A + ConstantB * B for each pair of values in Scalar List A and Scalar List B and returns the value in the new Scalar List. By default this (constants = 1) just adds the two values. Set The function can also be used to Linear Interpolate, by setting |
| Scalar Blend In Place | Computes ConstantA * A + ConstantB * B for each pair of values in ScalarListA and ScalarListB and return in ScalarListB. By default this (constants = 1) just adds the two values. Set Can also be used to Linear Interpolate, by setting |
| Scalar Multiply | Computes Scalar Multiplier * A * B for each pair of values in Scalar List A and Scalar List B, and returns the values in the new Scalar List. |
| Scalar Multiply In Place | Computes Scalar Multiplier * A * B for each pair of values in Scalar List A and Scalar List B, and returns the values in Scalar List B. |
| Constant Scalar Multiply | Computes Constant * Scalar for each value in Scalar List, and returns the values in the new Scalar List. |
| Constant Scalar Multiply In Place | Computes Scalar Multiplier A * B for each pair of values in Scalar List A and Scalar List B, and returns the values in the current Scalar List. |
MaterialID Functions
Functions for manipulating Material IDs of a mesh. A Material ID is a per-triangle integer and is not directly connected to any specific Material. Each Material ID is associated with a Mesh Section when converting to or from a Static Mesh.
| Node Name | Description |
|---|---|
| Get Has Material IDs | Returns true if the mesh has Material IDs available/enabled. |
| Enable Material IDs | Enables Material IDs on a mesh, initialize to 0. |
| Clear Material IDs | Resets all Material IDs on a mesh to 0. |
| Get Max Material ID | Returns the maximum Material ID currently set on a mesh. |
| Remap Material IDs | For all triangles with a Material ID matching a given value, and sets the Material ID to a new value. |
| Set All Triangle Material IDs | Sets the Material ID of all triangles in a mesh to the values in an input Index List. |
| Set Polygroup Material ID | Sets the Material ID of all triangles in a mesh that have a specified Polygroup ID (in a given Polygroup layer) to the specified Material ID. |
Vertex Values
You use these values to get and manipulate mesh values stored at vertices, including Vertex Colors
Multiple values, such as Normals, can be stored at a given vertex but these methods will only return one.
| Node Name | Description |
|---|---|
| Set Mesh Constant Vertex Color | Sets all vertex colors to a specific color. |
| Set Mesh Per Vertex Colors | Sets the color for every vertex using a Color List. |
| Get Mesh Per Vertex Colors | Gets a list of single vertex colors for each mesh vertex in the Target Mesh, derived from the Vertex Color Overlay. |
| Set Mesh Selection Vertex Color | Sets the colors in the Target Mesh's Vertex Color Overlay, identified by the Selection, to a constant value.
|
| Convert Mesh Vertex Colors SRGB To Linear | Apply an SRGB to Linear color transformation on all vertex colors. |
| Convert Mesh Vertex Colors Linear To SRGB | Apply a Linear to SRGB color transformation on all vertex colors. |
| Get Mesh Per Vertex Normals | Get a list of single normal vectors for each mesh vertex in the Target Mesh, derived from the Normals Overlay. |
| Get Mesh Per Vertex UVs | Get a list of single vertex UVs for each mesh vertex in the Target Mesh, derived from the specified UV Overlay. |
Texture Sampling and Creation
Functions for reading and creating texture data.
| Node Name | Description |
|---|---|
| Sample Texture 2D At UV Positions | Sample the given Texture Map at the list of UV positions and return the color at each position in the Color List output. |
| Create New Texture 2D Asset | Create a serialized Texture 2D Asset from a temporary UTexture2D. |
Baking
These functions bake data between a source and target mesh into texture or vertex color data. You can bake various mesh data such as normals, curvature, and ambient occlusion.
| Node Name | Description |
|---|---|
| Bake Texture | Creates Textures for the Target Mesh from data sampled in the Source Mesh. |
| Bake Vertex | Populates the vertex colors in the Target Mesh with the results of the Baking properties of the given Source Mesh. |
UV Functions
You use these functions to manipulate the UVs of a mesh.
| Node Name | Description |
|---|---|
| Get Num UV Sets | Gets the number of UV Layers on a Mesh. |
| Set Num UV Sets | Sets the number of UV Layers on a Mesh. |
| Get UV Set Bounding Box | Gets the 2D bounding box of all UVs in a UV Set. |
| CopyUVSet | Replaces target UV set with values from source UV set. |
| Translate Mesh UVs | Applies 2D Translation to all UVs, or a subset of UVs if you provide a Selection, in the UVSet Index. |
| Scale Mesh UVs | Applies 2D Scale to all UVs, or a subset of UVs if you provide a Selection, in the UVSet Index. |
| Rotate Mesh UVs | Apples 2D Rotation to all UVs, or a subset of UVs if you provide a Selection, in the UVSet Index. |
| Recompute Mesh UVs | Recomputes UVs for a Mesh based on different types of well-defined UV islands, such as existing UV islands, PolyGroups, or the Selection input. |
| Repack Mesh UVs | Packs the existing UV islands into standard UV space. |
| Set Mesh UVs From Planar Projection | Using Planar projection, set UVs for an entire mesh or a subset you define by the Selection input. |
| Set Mesh UVs From Box Projection | Using Box Projection, set UVs for an entire mesh or a subset you define by the Selection input. |
| Set Mesh UVs From Cylinder Projection | Using Cylinder Projection, set UVs for an entire mesh or a subset you define by the Selection input. |
| Auto Generate Patch Builder Mesh UVs | Computes new UVs using PatchBuilder method, and optionally pack. |
| Auto Generate X Atlas Mesh UVs | Computes new UVs using XAtlas, and optionally packs. |
| Get Mesh UVSize Info | Computes information about dimensions and areas for a UVSet of a Mesh, with an optional Mesh Selection. |
| Get Mesh Per Vertex UVs | Gets a list of single vertex UVs for each mesh vertex in the TargetMesh, derived from the specified UV Overlay. |
| Copy Mesh UV Layer To Mesh | Copies the 2D UVs from the given UVSet Index in Copy From Mesh to the 3D vertex positions in Copy To UV Mesh. Polygroup IDs and Material IDs are preserved in the UV Mesh. |
| Copy Mesh To Mesh UV Layer | Transfers the 3D vertex positions and triangles of Copy From UVMesh to the given UV Layer identified by To UV Set Index of Copy To Mesh. The 3D positions (X,Y,Z) will be copied as UV positions (X,Y). |
PolyGroup Functions
Functions for manipulating PolyGroups of a mesh. PolyGroups are per-triangle integers that implicitly define regions and patches of triangles in Modeling Tools and some Geometry Script operations. However, a PolyGroup layer is ultimately a per-triangle number, and you can use it for any other purpose.
| Node Name | Description |
|---|---|
| Get Has Polygroups | Returns true if the mesh has a standard Polygroup Layer. |
| Enable Polygroups | Enables standard Polygroup Layer on a Mesh. |
| GetNum Extended Polygroup Layers | Returns the count of extended Polygroup Layers. Note that extended Polygroup Layers are not yet fully supported by all operations or modeling tools. |
| Set Num Extended Polygroup Layers | Sets the number of extended Polygroup Layers on a Mesh. |
| Clear Polygroups | Resets the triangle Polygroup assignments to a constant value for a given Polygroup Layer. |
| Copy Polygroups Layer | Copies Polygroups from one layer to another. |
| Convert UV Islands To Polygroups | Creates and assigns a new Polygroup for each disconnected UV island of a Mesh. |
| Convert Components To Polygroups | Creates and assigns a new Polygroup for each disconnected component of a Mesh. |
| Compute Polygroups From Angle Threshold | Sets Polygroups by partitioning the mesh based on an edge crease/opening-angle. |
| Compute Polygroups From Polygon Detection | Identifies polygons and assigns Polygroup IDs. |
Mesh Geometric Queries
These functions allow for high-level geometric queries of a mesh.
| Node Name | Description |
|---|---|
| Get Mesh Bounding Box | Computes the bounding box of the mesh vertices. |
| Get Mesh Volume Area | Computes the volume and area of the mesh. |
| Get Is Closed Mesh | Returns true if the mesh is closed, such as no topological boundary edges. |
| Get Num Open Border Loops | Returns the number of open border loops, such as "holes" in the mesh. |
| Get Num Open Border Edges | Returns the number of topological boundary edges in the mesh. |
| Get Num Connected Components | Returns the number of separate connected-components in the mesh, such as "triangle patches" connected by shared edges. |
| Compute Mesh Convex Hull | Computes the Convex Hull of a given Mesh, or part of the mesh you define by the Selection input, and returns in a separate mesh. |
| Compute Mesh Swept Hull | Computes a 2D swept-hull of the input mesh and returns in a separate mesh. |
| Compute Mesh Convex Decomposition | Computes a Convex Hull Decomposition of the given Target Mesh. Assuming more than one hull is requested, multiple hulls will be returned that attempt to approximate the mesh. There is no guarantee that the entire mesh is contained in the hulls. |
PolyPath
These functions perform PolyPath manipulations. A PolyPath is a path defined by an ordering of vertices.
| Node Name | Description |
|---|---|
| Get Poly Path Num Vertices | Returns the number of vertices in the PolyPath |
| Get Poly Path Last Index | Returns the index of the last vertex in the PolyPath. |
| Get Poly Path Vertex | Returns the 3D location of the specified vertex. |
| Get Poly Path Tangent | Returns the local tangent vector of the PolyPath at the specified vertex index. |
| Get PolyPath Arc Length | Returns the length of the PolyPath. |
| Get NearestVertexIndex | Returns the index of the nearest PolyPath vertex to the specified point in 3D. |
| Flatten To 2D On Axis | Creates a 2D flatten copy of the path, by dropping the given axis and using the other two coordinates as the new X, Y coordinates. |
| Convert Spline To PolyPath | Samples the positions from a USplineComponent into a PolyPath, based on the given Sampling Options. |
| Convert PolyPath To Array | Populates an array of 3D vectors with the PolyPath vertex locations. |
| Convert Array To PolyPath | Creates a PolyPath from an array of 3D position vectors. |
| Convert PolyPath To Array Of Vector 2D | Creates an array of 2D Vectors with the PolyPath vertex locations projected onto the XY plane. |
| Convert Array Of Vector 2D To PolyPath | Creates a PolyPath from an array of 2D position vectors. The Z-coordinate of the corresponding PolyPath vertices will be zero. |
| Create Circle Path 3D | Creates a closed circle around the origin on the XY plane, then is repositioned by the Transform input. |
| Create Circle Path 2D | Creates a closed circle on the XY plane around the given Center. For closed paths, the end vertex is not a duplicate of the start vertex. |
| Create Arc Path 3D | Creates an open arc around the origin on the XY plane, then is repositioned by the Transform input. |
| Create Arc Path 2D | Creates an open arc on the XY plane around the given Center. |
Mesh Comparisons
These functions enable comparisons between two meshes. These nodes do not modify either mesh through their usage.
| Node Name | Description |
|---|---|
| Is Same Mesh As | Returns true if the two input meshes are equivalent under the comparisons defined by the input options. |
| Measure Distances Between Meshes | Measures the min/max and average closest-point distances between two meshes. |
| Is Intersecting Mesh | Returns true if the two input meshes (with optional transforms) are geometrically intersecting. |
BVH & Spatial Queries
These functions create and query a Bounding Volume Hierarchy (BVH) object for a mesh.
| Node Name | Description |
|---|---|
| Build BVH For Mesh | Builds a BVH object for a mesh that can be used by Is BVH Valid For Mesh, Rebuild BVH for Mesh, Find Nearest Point On Mesh, Find Nearest Ray Intersection With Mesh, and Is Point Inside Mesh nodes. The function returns a Geometry Script Dynamic Mesh BVH struct. |
| Is BVH Valid For Mesh | Checks if the BVH object can still be used with the Mesh — it generally returns false if the mesh has been changed. |
| Rebuild BVH For Mesh | Rebuilds the BVH object for the mesh in-place, which can reduce memory allocations, compared to building a new BVH. |
| Find Nearest Point On Mesh | Finds the nearest point on the mesh/BVH to a given 3D point. |
| Find Nearest Ray Intersection With Mesh | Finds the nearest intersection of a 3D ray with the mesh/BVH. |
| Is Point Inside Mesh | Tests if a point is inside the mesh/BVH using the Fast Winding Number query. |
Utilities
These helper functions are useful in Geometry Script mesh processing and procedural generators.
| Node Name | Description |
|---|---|
| Create Dynamic Mesh Pool | Creates a new Dynamic Mesh Pool object. |
| Create Unique New Asset Path Name | Create a new unique asset name given a base path and base asset name, which is useful with functions like Create New Static Mesh Asset From Mesh. This node only works in the Editor. |
| Get Mesh Info String | Returns a debug string that contains mesh statistics and other information. |
| Sample Spline To Transforms | Sample a USplineComponent into a list of FTransforms, based on the given Sampling Options. |
Glossary
| Term | Definition |
|---|---|
| Overlay | A data structure representing a type of vertex data applied to a mesh.These types include: vertex color, normal, tangent, and UV. Multiple values of the specified type can be stored at a single vertex. In such cases, depending on the type, one of the following occurs: the last value is used, the values are averaged, or an arbitrary value is used. |
| One-ring | The neighboring vertices of the selected vertex, connected by an edge. 
The one-ring of vertex M. |
| UV Set/Layer | Contains the UV coordinates of a mesh, also referred to as the UV Channel. You can use multiple UV Channels to represent different UV maps. |