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Path Spline Mesh

PCGEx | Path : Spline Mesh

Create SplineMesh components from paths

The Path Spline Mesh node generates spline meshes along a path with detailed per-segment settings, allowing for mesh and data distribution from asset collections or attribute sets, and includes advanced options for tangents, scaling, justification, and distribution to control mesh behavior and appearance.

Paths
Paths to be used for SplineMesh

Table of content

The Path Spline Mesh node creates a spline mesh from an existing path, with extensive per-segment settings. It works very similarily to the Asset Staging node and uses the same set of options.

details/paths-spline-mesh/lead.png

Properties


Property Description
Closed loop  
Scope The scope/selection of input data that are to be processed as closed paths or not.
-All processes all input as selected below.
-All but tagged inverts the scope based on tags.
Default is, all paths are considered open, unless they are tagged with ClosedLoop.
Closed Loop Whether to consider input data that are part of the scope as closed loop or not.
Comma Separated Tags Tags to check for. Any match uses the inverse of the above value.

Asset Collection


Controls the collection of meshes & data that will be distributed to the path on its individual segments.

Property Description
Source Which type of source to use for the asset collection.
Can be either Asset for an Asset Collection picker, or Attribute Set, which will reveal a new input pin that accepts an attribute set.
Asset Collection If Asset is selected as a source, this is the Asset Collection that will be used for staging points.
See Available Asset Collections.

When using the Attribute Set source, the node will create a temp, internal Asset Collection from the source attribute set.

Attribute Set Details
Asset Path Source Attribute The name of the attribute within the Attribute Set that contains the entry’ Asset Path.
FSoftObjectPath is preferred, but FString and FName are supported.
Weight Source Attribute The name of the attribute within the Attribute Set that contains the entry’ Weight.
int32 is preferred, but float, double and int64 are supported.
Category Source Attribute The name of the attribute within the Attribute Set that contains the entry’ Category.
FName is preferred, but FString is supported.

While it’s a needed option, keep in mind that using an attribute set prevents access to any asset cached data. As such, all assets from the Attribute Set will be first loaded (asynchronously) in memory in order to compute their bounds; before the node execution can properly start.

Tangents


While disabled by default, Tangents play a crucial role in giving the spline mesh a correct deformation. It’s generally preferable to compute some using Write Tangents beforehand.

Property Description
Apply Custom Tangents When enabled, applies FVector tangents attributes to path segments.
Arrive Tangent Attribute Per-point attribute to read the arrive tangent from.
Leave Tangent Attribute Per-point attribute to read the leave tangent from.
Spline Mesh Axis Chooses which mesh local axis will be aligned along the spline mesh’ segment.

Note that the way arrive/leave tangent works is that each spline mesh segment uses the current point’ leave value, and the next point arrive value.

The axis picked for Spline Mesh Axis will be ignored for Scale to Fit & Justification.

Scale to Fit

details/paths-spline-mesh/scale-to-fit.png

Scale the spawned asset bounds in order to fit within the host point’ bounds.

Note that the maths are computed against the point’ bounds, not the segment AABB.

Scale to Fit Mode Which type of scale-to-fit mode is to be applied. None disables this section, Uniform applies the same rule to each individual component, while Individual lets you pick per-component rules.
Scale to Fit (value) If Asset is selected as a source, this is the Asset Collection that will be used for staging points.

You can use the following rules:

Scale to Fit
details/assets-staging/enum-stf-none.png None
Disable the scaling rule.
details/assets-staging/enum-stf-fill.png Fill
Scale the asset so it fills the point’ bounds.
details/assets-staging/enum-stf-min.png Min
Scale the asset so it fits snuggly within the minimum point’ bounds.
details/assets-staging/enum-stf-max.png Max
Scale the asset so it fits snuggly within the maximum point’ bounds.
details/assets-staging/enum-stf-avg.png Average
Scale the asset so it fits the average of the point’ bounds.

Justification

details/paths-spline-mesh/justification.png

Offset the spawned asset bounds relative to the host point’ bounds.
Justification is done & tweaked per-component.

Note that the maths are computed against the point’ bounds, not the segment AABB.

Per component
From The location within the Asset bounds that will be justified To the point’ bounds.
i.e, from which location in the asset do i start moving.
To The location withn the Point bounds to which the Asset bounds will be justified.
i.e, to which location in the point do i want to go.
Consolidated custom inputs
Custom from Vector Attribute An FVector whose individual component will be used to drive From properties set to Custom.
Prefer this consolidated approach if you’re using custom values on more than one component.
Custom to Vector Attribute An FVector whose individual component will be used to drive To properties set to Custom. Prefer this consolidated approach if you’re using custom values on more than one component.
Justify to One If enabled, justification ignore the original path’ point bounds, and uses 1,1,1 bounds instead.

From

You can use the following rules for From:

Justify From
details/assets-staging/enum-justify-from-center.png Center
Uses the asset bounds’ local center as reference point.
details/assets-staging/enum-justify-from-min.png Min
Uses the asset bounds’ min as reference point.
details/assets-staging/enum-justify-from-max.png Max
Uses the asset bounds’ max as reference point.
details/assets-staging/enum-justify-from-pivot.png Pivot
Uses the asset pivot as reference point, ignoring bounds.
details/assets-staging/enum-justify-from-custom.png Custom
Uses a lerped reference point between the asset bounds’ min & max.
Value is expected to be in the range 0-1 but isn’t clamped.

To

You can use the following rules for To:

Justify To
details/assets-staging/enum-justify-to-same.png Same
Auto-selects the same justification as From, but computed against the point’ bounds.
details/assets-staging/enum-justify-to-center.png Center
Uses the point bounds’ local center as reference point.
details/assets-staging/enum-justify-to-min.png Min
Uses the point bounds’ min as reference point.
details/assets-staging/enum-justify-to-max.png Max
Uses the point bounds’ max as reference point.
details/assets-staging/enum-justify-to-pivot.png Pivot
Uses the point bounds’ pivot, ignoring bounds.
details/assets-staging/enum-justify-to-custom.png Custom
Uses a lerped reference point between the asset bounds’ min & max.
Value is expected to be in the range 0-1 but isn’t clamped.

Distribution Settings

Distribution drives how assets are selected within the collection & assigned to points.

Seed components Seed components lets you choose which seed source you want to combined to drive randomness.
None Will only use the point’ seed.
Local The local user-set seed see property below
Settings This node’ Settings seed.
Component The parent PCG component’ seed.

Distribution

Distribution
Index Index-based selection within the collection.
Enable a lot of additional options.
Random Plain old random selection.
Weighted Random Weighted random selection, using entries’ Weight property.

Index Settings

Index settings offer granular controls over what the Index actually is, and how it is used.

Index Setting Description
Pick Mode Choose in which ordered context the input index should be used.
Index Safety Defines how the index value should be sanitized/post-processed.
Index Source The source of the index value.
Remap Index to Collection Size If enabled, the input index is first remapped to the size of the collection.
This enable the use of basically any input value and distribute the entierety of the collection over its range.
Note that this can have a noticeable performance impact since all input indices must be loaded in memory first to find the min/max range.
Truncate Remap Lets you choose how the remapped value (floating point) should be truncated to an integer.

Index Safety

The index safety property controls how invalid/out of bounds input values are handled.

Safety method  
Ignore Invalid indices will be ignored and won’t be processed further.
Tile Index is tiled (wrapped around) the context’ valid min/max range.
Clamp Index is clamped between the context’ valid min/max range.
Yoyo Index bounces back and forth between the context’ valid min/max range.

Target Actor

Lets you pick which actor to attach the spline components to.
Uses the PCG Component’ owner if the provided value is invalid.

Additional Outputs

Lets you output the Weight of the selection to each node, using different post-processing methods.
This can be very handy to identify “rare” spawns and preserve them during self-pruning operations.

Tagging Components

Lets you pick which tags to add/forward to the output spline mesh components.

Property Description
Grab Tags Pick which tags from the asset collection should be grabbed and added to the component.
See Entries & Collections Tags.
Forward Input Data Tags If enabled, tags associated with the currently processed dataset will be forwarded to the components.
More TBD