Data

Types

Numbers

Icon	Name	Inputs	Outputs
	Number	Number Box	double

Simply put, a number node allows one to add a number to the canvas by typing it in the number box. This can be an integer, decimal, negative number, etc. There are other options for adding numbers to the canvas, including sliders, which we'll demonstrate in the exercise at the end of this section.

Booleans

Icon	Name	Inputs	Outputs
	Boolean	True/False	boolean

Numeric variables can store a whole range of different numbers. Boolean variables can only store two values referred to as Yes or No, True or False, 1 or 0. Obviously we never use booleans to perform calculations because of their limited range. We use booleans to evaluate conditions.

Strings

Icon	Name	Inputs	Outputs
	String	Text Box	string

A string is programming lingo for text. We know that number can drive parameters, and we can do the same with text, which we demonstrate in section 4.4.

Geometry

Points

Name/Syntax	Inputs	Outputs
Point.ByCoordinates	x,y,z	Point
Point.ByCylindricalCoordinates	cs,angle,elevation,radius	Point
Point.BySphericalCoordinates	cs,phi,theta,radius	Point

A point is a location in space. For this primer, our coordinate system is X,Y, and Z. A point has a value for X, a value for Y, and a value for Z.

Vectors

Name/Syntax	Inputs	Outputs
Vector.ByCoordinates	x,y,z	Vector
Vector.ByTwoPoints	start,end	Vector
Vector.XAxis	none	Vector
Vector.YAxis	none	Vector
Vector.ZAxis	none	Vector

A vector is a geometric quantity describing Direction and Magnitude. Vectors are abstract; ie. they represent a quantity, not a geometrical element.

Planes

Name/Syntax	Inputs	Outputs
Vector.ByCoordinates	p1,p2,p3	Plane
Vector.ByTwoPoints	origin,normal	Plane
Plane.XY	none	Plane
Plane.XZ	none	Plane
Plane.YZ	none	Plane

Planes are “Flat” and extend infinitely in two directions, defining a local coordinate system.

Nurbs

Icon	Name/Syntax	Inputs	Outputs
	NurbsSurface.ByControlPoints	ControlVertices,uDegree,vDegree	NurbsSurface
	NurbsCurve.ByControlPoints	points	NurbsCurve

NURBS (non-uniform rational B-splines) are mathematical representations that can accurately model any shape from a simple 2D line, circle, arc, or box to the most complex 3D free-form organic surface or solid. They are created with rational algorithms and are infinitely differentiable.

Meshes

Icon	Name/Syntax	Inputs	Outputs
	Mesh.ByPointsFaceIndices	vertexPositions,indices	Mesh

A mesh is a collection of vertices, edges and faces which define a polyhedral object. Meshes are often used for rendering and animation, and are generally 'lighter weight' than nurbs (meaning, they have smaller file sizes and render more quickly). The tradeoff is that meshes are limited in their resolution.

Meshes vs. Nurbs

Generally, we can say that Nurbs are to Meshes as Vectors are to Pixels. They are significantly different geometry types, and using the propery geometry type for surfaces is critical for parametric modeling and file management.

Surfaces

Name/Syntax	Inputs	Outputs
Surface.ByLoft	crossSections	Surface
Surface.ByPatch	closedCurve	Surface
Surface.ByPerimeterPoints	points	Surface
Surface.BySweep	profile,path	Surface
Surface.ByRevolve	profile,axisOrigin,axisDirection,startAngle,sweepAngle	Surface

A surface is two-dimensional topological manifold. Rather than deciphering what that means, let's just saw a surface is geometry that does not have thickness. This is how a surface is different from a solid.

Solids

Name/Syntax	Inputs	Outputs
Solid.ByUnion	solids	Solid
Solid.ByJoinedSurfaces	facesOfSolid	Solid
Solid.ByLoft	crossSections	Solid
Solid.BySweep	profile,path	Solid
Solid.ByRevolve	profile,axisOrigin,axisDirection,startAngle,sweepAngle	Solid

A solid is three-dimensional geometry. A solid has thickness and can exist in the real world, unlike surfaces, curves, vectors, and points (at least as far as we can see). In Dynamo, a solid can be defined as a collection of surfaces, called a polysurface.

"Null"

Icon	Name/Syntax	Inputs	Outputs
	Object.IsNull	obj	bool

The 'null' object represents the absense of data. This is abstract, but you will likely come across this while working with visual programming. Testing for nulls and removing nulls from data structure is a crucial part to creating robust parametric models.

4.1.2 Hierarchy

Item(s)

Icon	Name/Syntax	Inputs	Outputs
	List.GetItemAtIndex	list,index	var[]...[]

Simply put, an item represents one single value, whether by itself or as part of a list. This can be any data type.

List(s)

Icon	Name/Syntax	Inputs	Outputs
	List.Create	index0, index1...	list

data