🝖 Dot Product

PCGEx | Filter : Dot

Compares the dot product of two direction vectors against a third value.

Filter

A single filter definition

Table of content

Properties
- Dot Comparison Details
- Comparison modes

The Dot Filter compares the dot product value of two directions.

details/filter-ecosystem/filter-compare-dot-lead.png

Properties

Property	Description
Operand A
Operand A	The first attribute of the comparison. Read as `FVector` direction.
Transform Operand A	If enabled, the Operand A direction will be transformed by the tested’ point transform.

Operand B
Compare Against	Type of operand B. Can be a per-point `Attribute`, or an easily overridable `Constant`.
Operand B (Constant or Attribute)	Operand B value, used to compute the dot product with. Read as `FVector` direction.
Transform Operand A	If enabled, the Operand A direction will be transformed by the tested’ point transform.

Dot Comparison Details

Property	Description
Comparison	Which comparison to use. See Numeric comparisons.
Dot Units	Let you choose to work either with normalized dot range (`-1 / 1`) or degrees. This affects how the attribute Dot value will be interpreted as well.
Unsigned Dot	When enabled, the comparison will occur against an absolute dot value. This is especially useful when testing against undirected lines.
Dot Value	The type of value used for this probe’ search radius; either a `Constant` value or fetched from an`Attribute`
(Dot or Degrees) Constant	Constant to compare against.
(Dot or Degrees) Attribute	Constant to compare against.
(Dot or Degrees) Tolerance	Comparison tolerance, if the selected comparison is an approximative (`~`) one.

Comparison modes

Comparison	Data
==	Strictly equal.
!=	Strictly not equal.
>=	Equal or greater.
<=	Equal or smaller.
>	Strictly greater.
<	Strictly smaller.
~=	Nearly equal.
!~=	Nearly not equal.

Approximative comparison will reveal an additional parameter, dubbed Tolerance. This represents the size of acceptable approximation for the comparison to pass. For example, when checking if 0.5 ~= 0.4 with a tolerance of 0.1 will return true.

Large tolerances can be a great, cheap way to achieve results akin to a “within range” comparison!