diff --git a/Sources/SwiftSCAD/Environment/Environment.swift b/Sources/SwiftSCAD/Environment/Environment.swift
index b12c30a..2a86372 100644
--- a/Sources/SwiftSCAD/Environment/Environment.swift
+++ b/Sources/SwiftSCAD/Environment/Environment.swift
@@ -3,14 +3,14 @@ import Foundation
 /// `Environment` provides a flexible container for environment-specific values influencing the rendering of geometries.
 ///
 /// You can use `Environment` to customize settings and attributes that affect child geometries within SwiftSCAD. Modifiers allow for dynamic adjustments of the environment, which can be applied to geometries to affect their rendering or behavior.
-public struct Environment {
-    private let values: [ValueKey: Any]
+public struct Environment: Sendable {
+    private let values: [ValueKey: any Sendable]
 
     public init() {
         self.init(values: [:])
     }
 
-    init(values: [ValueKey: Any]) {
+    init(values: [ValueKey: any Sendable]) {
         self.values = values
     }
 
@@ -18,7 +18,7 @@ public struct Environment {
     ///
     /// - Parameter newValues: A dictionary of values to add to the environment.
     /// - Returns: A new `Environment` instance with the added values.
-    public func setting(_ newValues: [ValueKey: Any]) -> Environment {
+    public func setting(_ newValues: [ValueKey: any Sendable]) -> Environment {
         Environment(values: values.merging(newValues, uniquingKeysWith: { $1 }))
     }
 
@@ -28,7 +28,7 @@ public struct Environment {
     ///   - key: The key for the value to update or add.
     ///   - value: The new value to set. If `nil`, the key is removed from the environment.
     /// - Returns: A new `Environment` instance with the updated values.
-    public func setting(key: ValueKey, value: Any?) -> Environment {
+    public func setting(key: ValueKey, value: (any Sendable)?) -> Environment {
         var values = self.values
         values[key] = value
         return Environment(values: values)
@@ -38,14 +38,14 @@ public struct Environment {
     ///
     /// - Parameter key: The key of the value to access.
     /// - Returns: The value associated with `key` if it exists; otherwise, `nil`.
-    public subscript(key: ValueKey) -> Any? {
+    public subscript(key: ValueKey) -> (any Sendable)? {
         values[key]
     }
 }
 
 public extension Environment {
     /// Represents a key for environment values.
-    struct ValueKey: RawRepresentable, Hashable {
+    struct ValueKey: RawRepresentable, Hashable, Sendable {
         public var rawValue: String
 
         public init(rawValue: String) {
diff --git a/Sources/SwiftSCAD/Environment/Facets.swift b/Sources/SwiftSCAD/Environment/Facets.swift
index 8a7bd0f..1acc33a 100644
--- a/Sources/SwiftSCAD/Environment/Facets.swift
+++ b/Sources/SwiftSCAD/Environment/Facets.swift
@@ -2,7 +2,7 @@ import Foundation
 
 public extension Environment {
     /// An enumeration representing the method for calculating the number of facets (or segments) used in rendering circular geometries.
-    enum Facets {
+    enum Facets: Sendable {
         /// Specifies a fixed number of facets for all circles, regardless of size.
         case fixed (Int)
 
diff --git a/Sources/SwiftSCAD/Environment/Operation.swift b/Sources/SwiftSCAD/Environment/Operation.swift
index dc390ec..7ed0143 100644
--- a/Sources/SwiftSCAD/Environment/Operation.swift
+++ b/Sources/SwiftSCAD/Environment/Operation.swift
@@ -4,7 +4,7 @@ public extension Environment {
     private static let key = Environment.ValueKey(rawValue: "SwiftSCAD.Operation")
 
     /// Represents a geometric operation, specifically for determining if geometries are being added or subtracted.
-    enum Operation {
+    enum Operation: Sendable {
         /// Represents the addition of geometries.
         case addition
         /// Represents the subtraction of geometries, typically used for creating holes or negative spaces within another geometry.
diff --git a/Sources/SwiftSCAD/Operations/Alignment/Alignment.swift b/Sources/SwiftSCAD/Operations/Alignment/Alignment.swift
index 772a31e..fd06bc7 100644
--- a/Sources/SwiftSCAD/Operations/Alignment/Alignment.swift
+++ b/Sources/SwiftSCAD/Operations/Alignment/Alignment.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-public enum AxisAlignment: Equatable {
+public enum AxisAlignment: Equatable, Sendable {
     case min
     case mid
     case max
@@ -14,7 +14,7 @@ public enum AxisAlignment: Equatable {
     }
 }
 
-public struct GeometryAlignment2D: Equatable {
+public struct GeometryAlignment2D: Equatable, Sendable {
     internal let x: AxisAlignment?
     internal let y: AxisAlignment?
 
@@ -33,7 +33,7 @@ public struct GeometryAlignment2D: Equatable {
     }
 }
 
-public struct GeometryAlignment3D: Equatable {
+public struct GeometryAlignment3D: Equatable, Sendable {
     internal let x: AxisAlignment?
     internal let y: AxisAlignment?
     internal let z: AxisAlignment?
diff --git a/Sources/SwiftSCAD/Operations/Extrude/Edge Profiles/EdgeProfile.swift b/Sources/SwiftSCAD/Operations/Extrude/Edge Profiles/EdgeProfile.swift
index 147dce5..10bde26 100644
--- a/Sources/SwiftSCAD/Operations/Extrude/Edge Profiles/EdgeProfile.swift	
+++ b/Sources/SwiftSCAD/Operations/Extrude/Edge Profiles/EdgeProfile.swift	
@@ -1,7 +1,7 @@
 import Foundation
 
 /// The profile of an edge
-public enum EdgeProfile: Equatable {
+public enum EdgeProfile: Equatable, Sendable {
     /// Represents an edge modified to be rounded.
     /// - Parameter radius: The radius of the curvature applied to the edge, determining the degree of roundness.
     case fillet (radius: Double)
diff --git a/Sources/SwiftSCAD/Shapes/2D/Text/Environment+Text.swift b/Sources/SwiftSCAD/Shapes/2D/Text/Environment+Text.swift
index 0f18c2d..e5b4c26 100644
--- a/Sources/SwiftSCAD/Shapes/2D/Text/Environment+Text.swift
+++ b/Sources/SwiftSCAD/Shapes/2D/Text/Environment+Text.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 internal extension Environment {
-    struct TextAttributes {
+    struct TextAttributes: Sendable {
         var font: String?
         var fontStyle: String?
         var fontSize: Double?
@@ -35,7 +35,6 @@ internal extension Environment {
             e = e.settingTextAttribute(\.fontSize, value: size)
         }
         return e
-
     }
 
     func withTextAlignment(horizontal: Text.HorizontalAlignment? = nil, vertical: Text.VerticalAlignment? = nil) -> Environment {
diff --git a/Sources/SwiftSCAD/Shapes/2D/Text/Text.swift b/Sources/SwiftSCAD/Shapes/2D/Text/Text.swift
index 45972e5..fb382e0 100644
--- a/Sources/SwiftSCAD/Shapes/2D/Text/Text.swift
+++ b/Sources/SwiftSCAD/Shapes/2D/Text/Text.swift
@@ -23,7 +23,7 @@ public struct Text: Geometry2D {
     /// An enumeration representing the horizontal alignment options for text geometry.
     ///
     /// Use these options with ``Geometry2D/usingTextAlignment(horizontal:vertical:)`` to set the horizontal alignment of your text geometry.
-    public enum HorizontalAlignment: String {
+    public enum HorizontalAlignment: String, Sendable {
         /// Aligns the text to the left.
         case left
         /// Centers the text horizontally.
@@ -40,7 +40,7 @@ public struct Text: Geometry2D {
     /// - `bottom`: Aligns the text to the bottom.
     ///
     /// Use these options with ``Geometry2D/usingTextAlignment(horizontal:vertical:)`` to set the vertical alignment of your text geometry.
-    public enum VerticalAlignment: String {
+    public enum VerticalAlignment: String, Sendable {
         /// Aligns the text to the top.
         case top
         /// Centers the text vertically.
diff --git a/Sources/SwiftSCAD/Values/Angle/Angle.swift b/Sources/SwiftSCAD/Values/Angle/Angle.swift
index 28d10f0..406c5dc 100644
--- a/Sources/SwiftSCAD/Values/Angle/Angle.swift
+++ b/Sources/SwiftSCAD/Values/Angle/Angle.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 /// A value representing a geometric angle
-public struct Angle {
+public struct Angle: Sendable {
     /// The angle expressed in radians
     public let radians: Double
 
diff --git a/Sources/SwiftSCAD/Values/Axis/Axes.swift b/Sources/SwiftSCAD/Values/Axis/Axes.swift
index 103aa0b..b9ef27f 100644
--- a/Sources/SwiftSCAD/Values/Axis/Axes.swift
+++ b/Sources/SwiftSCAD/Values/Axis/Axes.swift
@@ -10,7 +10,7 @@ public protocol Axes {
 
 /// A set of cartesian axes in two dimensions (X and/or Y)
 
-public struct Axes2D: Axes, OptionSet, Hashable {
+public struct Axes2D: Axes, OptionSet, Hashable, Sendable {
     public typealias Axis = Axis2D
 
     public let rawValue: Int
@@ -46,7 +46,7 @@ public struct Axes2D: Axes, OptionSet, Hashable {
 
 /// A set of cartesian axes in three dimensions (X, Y and/or Z)
 
-public struct Axes3D: Axes, OptionSet, Hashable {
+public struct Axes3D: Axes, OptionSet, Hashable, Sendable {
     public typealias Axis = Axis3D
 
     public let rawValue: Int
diff --git a/Sources/SwiftSCAD/Values/Axis/Axis.swift b/Sources/SwiftSCAD/Values/Axis/Axis.swift
index 7577c4d..80c45d5 100644
--- a/Sources/SwiftSCAD/Values/Axis/Axis.swift
+++ b/Sources/SwiftSCAD/Values/Axis/Axis.swift
@@ -1,13 +1,13 @@
 import Foundation
 
 /// One of the cartesian axes in two dimensions (X or Y)
-public enum Axis2D: Int, CaseIterable {
+public enum Axis2D: Int, CaseIterable, Sendable {
     case x
     case y
 }
 
 /// An enumeration representing the three Cartesian axes in a three-dimensional space: X, Y, and Z.
-public enum Axis3D: Int, CaseIterable {
+public enum Axis3D: Int, CaseIterable, Sendable {
     case x
     case y
     case z
@@ -28,7 +28,7 @@ public enum Axis3D: Int, CaseIterable {
 }
 
 /// A direction along an axis
-public enum AxisDirection {
+public enum AxisDirection: Sendable {
     /// The positive direction along an axis
     case positive
     /// The negative direction along an axis
diff --git a/Sources/SwiftSCAD/Values/Bezier/BezierCurve.swift b/Sources/SwiftSCAD/Values/Bezier/BezierCurve.swift
index 6e02d57..e8ad334 100644
--- a/Sources/SwiftSCAD/Values/Bezier/BezierCurve.swift
+++ b/Sources/SwiftSCAD/Values/Bezier/BezierCurve.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-internal struct BezierCurve <V: Vector> {
+internal struct BezierCurve <V: Vector>: Sendable {
     let controlPoints: [V]
 
     init(controlPoints: [V]) {
diff --git a/Sources/SwiftSCAD/Values/Bezier/BezierPath.swift b/Sources/SwiftSCAD/Values/Bezier/BezierPath.swift
index 19e18ee..6a86323 100644
--- a/Sources/SwiftSCAD/Values/Bezier/BezierPath.swift
+++ b/Sources/SwiftSCAD/Values/Bezier/BezierPath.swift
@@ -8,7 +8,7 @@ public typealias BezierPath3D = BezierPath<Vector3D>
 /// You can create a `BezierPath` by providing a starting point and adding curves and line segments to the path. 2D paths can be used to create `Polygon` shapes.
 ///
 /// To create a `BezierPath`, start with the `init(startPoint:)` initializer, specifying the starting point of the path. Then, you can chain calls to `addingLine(to:)`, `addingQuadraticCurve(controlPoint:end:)`, and `addingCubicCurve(controlPoint1:controlPoint2:end:)` to build a complete path.
-public struct BezierPath <V: Vector> {
+public struct BezierPath <V: Vector>: Sendable {
     let startPoint: V
     let curves: [BezierCurve<V>]
 
diff --git a/Sources/SwiftSCAD/Values/Boundary/Boundary.swift b/Sources/SwiftSCAD/Values/Boundary/Boundary.swift
index 3e98f85..9adaac9 100644
--- a/Sources/SwiftSCAD/Values/Boundary/Boundary.swift
+++ b/Sources/SwiftSCAD/Values/Boundary/Boundary.swift
@@ -3,7 +3,7 @@ import Foundation
 public typealias Boundary2D = Boundary<Vector2D>
 public typealias Boundary3D = Boundary<Vector3D>
 
-public struct Boundary<V: Vector> {
+public struct Boundary<V: Vector>: Sendable {
     internal let points: [V]
 
     internal init(points: [V]) {
diff --git a/Sources/SwiftSCAD/Values/Boundary/BoundingBox.swift b/Sources/SwiftSCAD/Values/Boundary/BoundingBox.swift
index 94b8ef1..c94c230 100644
--- a/Sources/SwiftSCAD/Values/Boundary/BoundingBox.swift
+++ b/Sources/SwiftSCAD/Values/Boundary/BoundingBox.swift
@@ -4,7 +4,7 @@ public typealias BoundingBox2D = BoundingBox<Vector2D>
 public typealias BoundingBox3D = BoundingBox<Vector3D>
 
 /// An axis-aligned bounding volume defined by its minimum and maximum corners, used to calculate and represent the bounding area or volume of shapes or points in a generic vector space.
-public struct BoundingBox<V: Vector> {
+public struct BoundingBox<V: Vector>: Sendable {
     /// The minimum corner point of the bounding volume, typically representing the "lower" corner in geometric space.
     public let minimum: V
     /// The maximum corner point of the bounding volume, typically representing the "upper" corner in geometric space.
diff --git a/Sources/SwiftSCAD/Values/Color.swift b/Sources/SwiftSCAD/Values/Color.swift
index 28df3d2..2cc18d3 100644
--- a/Sources/SwiftSCAD/Values/Color.swift
+++ b/Sources/SwiftSCAD/Values/Color.swift
@@ -1,10 +1,10 @@
 import Foundation
 
-public enum Color {
+public enum Color: Sendable {
     case components (red: Double, green: Double, blue: Double, alpha: Double)
     case named (Name, alpha: Double)
 
-    public enum Name: String {
+    public enum Name: String, Sendable {
         case lavender
         case thistle
         case plum
diff --git a/Sources/SwiftSCAD/Values/Corners/RectangleCornerRadii.swift b/Sources/SwiftSCAD/Values/Corners/RectangleCornerRadii.swift
index 4cf5e24..7eaa39a 100644
--- a/Sources/SwiftSCAD/Values/Corners/RectangleCornerRadii.swift
+++ b/Sources/SwiftSCAD/Values/Corners/RectangleCornerRadii.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-internal struct RectangleCornerRadii {
+internal struct RectangleCornerRadii: Sendable {
     let minXminY: Double
     let maxXminY: Double
     let maxXmaxY: Double
diff --git a/Sources/SwiftSCAD/Values/Corners/RectangleCorners.swift b/Sources/SwiftSCAD/Values/Corners/RectangleCorners.swift
index 8a66728..8c5f250 100644
--- a/Sources/SwiftSCAD/Values/Corners/RectangleCorners.swift
+++ b/Sources/SwiftSCAD/Values/Corners/RectangleCorners.swift
@@ -5,7 +5,7 @@ import Foundation
 /// `RectangleCorners` allows for specifying and manipulating individual corners or groups of corners of a rectangle.
 /// It is used for operations that involve corner-specific modifications, such as rounding corners.
 
-public struct RectangleCorners: OptionSet, Hashable {
+public struct RectangleCorners: OptionSet, Hashable, Sendable {
     public let rawValue: Int
 
     public init(rawValue: Int) {
diff --git a/Sources/SwiftSCAD/Values/Corners/RoundedCornerStyle.swift b/Sources/SwiftSCAD/Values/Corners/RoundedCornerStyle.swift
index e926f77..7e8b565 100644
--- a/Sources/SwiftSCAD/Values/Corners/RoundedCornerStyle.swift
+++ b/Sources/SwiftSCAD/Values/Corners/RoundedCornerStyle.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 /// Represents the style of rounded corners.
-public enum RoundedCornerStyle {
+public enum RoundedCornerStyle: Sendable {
     /// A regular circular corner.
     case circular
     /// A squircular corner, forming a more natural and continuous curve.
diff --git a/Sources/SwiftSCAD/Values/Rotation3D.swift b/Sources/SwiftSCAD/Values/Rotation3D.swift
index 9ba2245..e254394 100644
--- a/Sources/SwiftSCAD/Values/Rotation3D.swift
+++ b/Sources/SwiftSCAD/Values/Rotation3D.swift
@@ -1,10 +1,10 @@
 import Foundation
 
 /// A structure representing a rotation in 3D space.
-public struct Rotation3D {
+public struct Rotation3D: Sendable {
     internal var rotation: Rotation
 
-    internal enum Rotation {
+    internal enum Rotation: Sendable {
         case eulerAngles (x: Angle, y: Angle, z: Angle)
         case axis (Vector3D, angle: Angle)
     }
diff --git a/Sources/SwiftSCAD/Values/SCADValue.swift b/Sources/SwiftSCAD/Values/SCADValue.swift
index 6ca9168..1bf8930 100644
--- a/Sources/SwiftSCAD/Values/SCADValue.swift
+++ b/Sources/SwiftSCAD/Values/SCADValue.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-protocol SCADValue {
+protocol SCADValue: Sendable {
     var scadString: String { get }
 }
 
diff --git a/Sources/SwiftSCAD/Values/Transforms/AffineTransform.swift b/Sources/SwiftSCAD/Values/Transforms/AffineTransform.swift
index 35aeb88..9f04a34 100644
--- a/Sources/SwiftSCAD/Values/Transforms/AffineTransform.swift
+++ b/Sources/SwiftSCAD/Values/Transforms/AffineTransform.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-public protocol AffineTransform {
+public protocol AffineTransform: Sendable {
     associatedtype Vector: SwiftSCAD.Vector
     associatedtype Rotation
 
diff --git a/Sources/SwiftSCAD/Values/Transforms/AffineTransform2D.swift b/Sources/SwiftSCAD/Values/Transforms/AffineTransform2D.swift
index 9696bcc..9977905 100644
--- a/Sources/SwiftSCAD/Values/Transforms/AffineTransform2D.swift
+++ b/Sources/SwiftSCAD/Values/Transforms/AffineTransform2D.swift
@@ -4,7 +4,7 @@ import simd
 #endif
 
 /// An `AffineTransform2D` represents a 2D affine transformation using a 3x3 matrix.
-public struct AffineTransform2D: AffineTransform, Equatable {
+public struct AffineTransform2D: AffineTransform, Equatable, Sendable {
     private var matrix: Matrix3x3
 
     internal init(_ matrix: Matrix3x3) {
diff --git a/Sources/SwiftSCAD/Values/Transforms/AffineTransform3D.swift b/Sources/SwiftSCAD/Values/Transforms/AffineTransform3D.swift
index 1b38fe7..e0f4944 100644
--- a/Sources/SwiftSCAD/Values/Transforms/AffineTransform3D.swift
+++ b/Sources/SwiftSCAD/Values/Transforms/AffineTransform3D.swift
@@ -4,7 +4,7 @@ import simd
 #endif
 
 /// An `AffineTransform3D` represents a 3D affine transformation using a 4x4 matrix.
-public struct AffineTransform3D: AffineTransform, Equatable {
+public struct AffineTransform3D: AffineTransform, Equatable, Sendable {
     private var matrix: Matrix4x4
 
     private init(_ matrix: Matrix4x4) {
diff --git a/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix3x3.swift b/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix3x3.swift
index 940f831..7840865 100644
--- a/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix3x3.swift
+++ b/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix3x3.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-internal struct BasicMatrix3x3: Equatable {
+internal struct BasicMatrix3x3: Equatable, Sendable {
     typealias Row = [Double]
     typealias Column = [Double]
 
diff --git a/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix4x4.swift b/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix4x4.swift
index acad543..2c9074e 100644
--- a/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix4x4.swift
+++ b/Sources/SwiftSCAD/Values/Transforms/Matrix/BasicMatrix4x4.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-internal struct BasicMatrix4x4: Equatable {
+internal struct BasicMatrix4x4: Equatable, Sendable {
     typealias Row = [Double]
     typealias Column = [Double]
 
diff --git a/Sources/SwiftSCAD/Values/Vectors/Vector.swift b/Sources/SwiftSCAD/Values/Vectors/Vector.swift
index 9fed0ab..299afa5 100644
--- a/Sources/SwiftSCAD/Values/Vectors/Vector.swift
+++ b/Sources/SwiftSCAD/Values/Vectors/Vector.swift
@@ -1,6 +1,6 @@
 import Foundation
 
-public protocol Vector {
+public protocol Vector: Sendable {
     associatedtype Axes: SwiftSCAD.Axes
     associatedtype Transform: AffineTransform where Transform.Vector == Self
 
diff --git a/Sources/SwiftSCAD/Values/Vectors/Vector2D.swift b/Sources/SwiftSCAD/Values/Vectors/Vector2D.swift
index 9e473f7..72addc8 100644
--- a/Sources/SwiftSCAD/Values/Vectors/Vector2D.swift
+++ b/Sources/SwiftSCAD/Values/Vectors/Vector2D.swift
@@ -8,7 +8,7 @@ import Foundation
 /// let v2: Vector2D = [10, 15]
 /// ```
 ///
-public struct Vector2D: ExpressibleByArrayLiteral, SCADValue, Hashable {
+public struct Vector2D: ExpressibleByArrayLiteral, SCADValue, Hashable, Sendable {
     public var x: Double
     public var y: Double
 
diff --git a/Sources/SwiftSCAD/Values/Vectors/Vector3D.swift b/Sources/SwiftSCAD/Values/Vectors/Vector3D.swift
index e6ee4b0..955bfe2 100644
--- a/Sources/SwiftSCAD/Values/Vectors/Vector3D.swift
+++ b/Sources/SwiftSCAD/Values/Vectors/Vector3D.swift
@@ -7,7 +7,7 @@ import Foundation
 /// let v1 = Vector3D(x: 10, y: 15, z: 5)
 /// let v2: Vector3D = [10, 15, 5]
 /// ```
-public struct Vector3D: ExpressibleByArrayLiteral, SCADValue, Hashable {
+public struct Vector3D: ExpressibleByArrayLiteral, SCADValue, Hashable, Sendable {
     public var x: Double
     public var y: Double
     public var z: Double