Houdini 20.0 Nodes Geometry nodes

Add geometry node

Creates Points or Polygons, or adds points/polys to an input.

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If an input is specified, this OP adds points and polygons to it as specified below. If no input is specified, then it generates the points and polygons below as a new entity.

Extract points

Used in conjunction with a point expression, the Add op can be useful for extracting a specific point from another op. For example, to extract the X, Y and Z value of the fifth point, from a Grid SOP in geo1:

point("geo1/grid1",5,"P",0),point("geo2/grid1",5,"P",1), point("geo3/grid1",5,"P",2)

Points added in this way are appended to the end of the point list if a Source is specified. Click the Information Pop-up on the op Tile to find out how many points there are. For example, if you have added two points and there are 347 points (from 0 to 346), you have added the last two point numbers: 345 and 346.

Create a specific number of points

Create an Add SOP and set it to create a single point, then append a Copy SOP and set its number of copies to the (possibly animated) number of points you want.

This works correctly even when number of points is 0, unlike some other approaches.




The three leftmost input fields represent the X,Y and Z coordinates of the point. The last input field represents the spline weight of the point. If the point is later used to create a spline (NURBS or Bezier) primitive, the weight will influence the shape of the primitive and may cause that primitive to become rational. Polygons and metaballs are not affected by this weight.

X, Y, Z, and W can be constants (numbers) or variables.

Delete Geometry But Keep the Points

This will destroy all the polygons, NURBs, and other primitives, leaving only the points intact.

Polygons: By Pattern


Create a fixed number of polygons by specifying a point pattern for each polygon Enter connection lists here to create polygons.

eg1: 1 2 3 4
eg2: 1 3-15 16 8
eg3: 1-234 820-410 235-409
eg4: 0-15:2
eg5: 0-15:2,3

Polygons: By Group


Create as many polygons as determined by the group field and by the grouping/skipping rules.


Subset of points to be connected.


Optionally join subgroups of points.


Increment to use for subgroup joining.


If group by attribute is specified, this attribute will be used to determine how to connect the polygons within the group. Points with the same attribute value will be connected together. The connection order will respect the point order of the group.

Remove Unused Points

Keep only the connected points.



Allows you to create a particle system out of a collection of points. Note that this will not create all the attributes you may want on a particle system. It is useful when you have a collection of points you wish to flag as a particle system for other operations, such as the Initial State, or as a source in DOPs.

To convert all your geometry into particles, turn on the Keep Points but Delete Primitives checkbox on the Points tab and then enable this with a blank group field.

Add Particle System

Controls whether a particle system primitive is created.

Particle Group

The points to add to the particle system. These are added in the order specified. If this field is left blank, all points will be added to the particle system.

Add Unused Points to Particle System

If no particle primitives exist, one will be created.

All points that are not part of any primitive will be appended to the first particle primitive.



Index of the last point in the geometry.


The centroid of the input.


The X extents of the bounding box of the input.


The Y extents of the bounding box of the input.


The Z extents of the bounding box of the input.


The size of the bounding box of the input.


AddItUp Example for Add geometry node

This network demonstrates the many uses of the Add SOP to build and manipulate geometry:

  • It is used to create points in space which can then be used to create polygons using designated patterns. These polygons can be open or closed. Futhermore, each point can be animated through expressions or keyframes.

  • It is used to both create points and grab points from other primitives. These points may be used in polygon creation.

  • The Add SOP may be utilized to create a polygon using points extracted from another polygonal object. A Group SOP allows for the creation of the point group that will be referenced by the Add SOP.

  • The Add SOP is used to create a polygon from a group of animated Null objects. An Object Merge SOP references the null points in SOPs which are then fed into an Add SOP for polygon generation. A Fit SOP, in turn, is used to create an interpolated spline from the referenced null points. The result is an animted spline.

  • The Add SOP is used to generate points without creating any primitives. Also, points from other objects can be extracted through the Add SOP.

  • Finally the Add SOP can additionally be used to procedurally create rows and columns.

Geometry nodes