Nodes Surface nodes

Nodes that control the shape of geometry.

Overview

Surface nodes create and manipulate geometry (curves, surfaces, metaballs, and so on). Surface nodes live inside a Geometry container object.

Surface node flags

Tip

Select a node and press 1 to set its display flag, or 2 to set its render flag.

Lock

Caches the input geometry and stops cooking the inputs to improve performance.

Bypass

Makes this node have no effect: passes the geometry through from the input to the output untouched. This is useful for testing and visualizing the effect the node is having in the viewer.

Template

Makes the geometry in this node visible and snappable, but unrenderable. This is useful for “guide” geometry, where you want to edit, visually match, or snap to, existing geometry.

Templated geometry only appears at the Geometry level, for use in modeling operations. It does not appear at the Scene level (it is not part of the “final” geometry of the object).

To prevent snapping to template geometry, open the snapping options window and turn off Apply to: Templates.

Selectable template

Ctrl-click the template flag to make the node’s geometry templated but selectable in the 3D viewer (at the Geometry level).

Like normal templated geometry, selectable templates only appear at the Geometry level, not the Scene level. This flag is equivalent to the “footprint” flag in previous versions of Houdini.

Display

This flag indicates which node provides the geometry for the container object. Only one node at a time can have the display flag.

Unlike an object’s display flag, this flag does not make a node visible or invisible in the viewer.

If you want geometry from more than one node in the object, use a Merge operator to merge the output of the nodes, then click the display flag on the Merge node.

A common problem when you first start working directly in the network is that you connect a node but it seems to have no effect. This is often because you haven’t clicked the display flag on the new node.

Render

The display flag normally indicates which node provides the geometry shown in the viewer and rendered by the renderer. You can set separate display and render flags, so one node provides the geometry for the viewer and a different node provides the geometry for the renderer. This lets you show proxy geometry in the viewer and render more detailed geometry.

Ctrl-click the display flag on another node to move the render flag there. The ring marks the display node, the circle marks the render node.

To fuse the display and render flags back together, Ctrl-click the active display flag.

Unload flag

The unload flag is available in list mode. When the unload flag is on, a surface node will not cache the geometry that passes through it.

This is useful for finished, static props and other non-time-dependent objects, where the geometry network cooks only once. Even if a node in a geometry is dynamic (its output changes depending on the frame number), you can turn on the unload flag of all the nodes above it to save memory.

(Unloading cached geometry will probably not decrease the total amount of memory Houdini uses, but it will free the memory for use in other parts of Houdini.)

To switch the network editor to list mode, right-click the network background and choose View nodes as a list, or move the mouse over the network editor and press T .

Usages in other examples

Example name Example for

Subtopics

Clear

  • Add
    Creates Points or Polygons, or adds points/polys to an input.
  • Align
    Aligns a group of primitives to each other or to an auxiliary input.
  • Assemble
    Cleans up a series of break operations and creates the resulting pieces.
  • Attrib Composite
    Composites vertex, point, primitive, and/or detail attributes between two or more selections.
  • Attrib Copy
    Copies attributes between groups of vertices, points, or primitives.
  • Attrib Create
    Adds or edits user defined attributes.
  • Attrib Mirror
    Copies and flips attributes from one side of a plane to another.
  • Attrib Promote
    Promotes or demotes attributes from one geometry level to another.
  • Attrib Reorient
    Modifies point attributes based on differences between two models.
  • Attrib String Edit
    Edits string attribute values.
  • Attrib Transfer
    Transfers vertex, point, primitive, and/or detail attributes between two models.
  • Attribute
    Renames or deletes point and primitive attributes.
  • Bake ODE
    Converts primitives for ODE solver.
  • Bake VEX
    Pre-shades mesh, Bezier or NURBs geometry with VEX surface and displacement VEX shaders.
  • Bake Volume
    Computes lighting values within volume primitives
  • Basis
    Provides operations for moving knots within the parametric space of a NURBS curve or surface.
  • Blast
    Deletes primitives, points, edges or breakpoints.
  • Blend Shapes
    Computes a 3D metamorphosis between shapes with the same topology.
  • Bound
    Creates an axis-aligned bounding box or sphere for the input geometry.
  • Box
    Creates a cube or six-sided rectangular box.
  • Break
    Breaks the input geometry using the specified cutting shape.
  • Bridge
    Skins trimmed surfaces or holes, creates highly controllable joins between arms and body, branches, or tube intersections.
  • Bulge
    Deforms the points in the first input using one or more magnets from the second input.
  • Cache
    Records and caches its input geometry for faster playback.
  • Cap
    Closes open areas with flat or rounded coverings.
  • Capture
    Supports Capture Region and Deform by assigning capture weights to capture regions.
  • Capture Correct
    Adjusts capture regions and capture weights.
  • Capture Layer Paint
    Lets you paint capture attributes directly onto geometry.
  • Capture Metaball
    Captures points on geometry to metaballs, similarly to capturing to a bone.
  • Capture Mirror
    Copies capture attributes from one half of a symmetric model to the other.
  • Capture Override
    Overrides the capture weights on individual points.
  • Capture Proximity
    Supports Capture Region and Deform by assigning capture weights to points based on distance to capture regions.
  • Capture Region
    Supports Capture and Deform operation by creating a volume within which points are captured to a bone.
  • Carve
    Slices, cuts or extracts points or cross-sections from a primitive.
  • Channel
    Reads sample data from a chop and converts it into point positions and point attributes.
  • Circle
    Creates open or closed arcs, circles and ellipses.
  • Clay
    Lets you deforms faces and surfaces by pulling points that lie directly on them.
  • Clean
    Helps clean up dirty models.
  • Clip
    Removes or groups geometry on one side of a plane, or creases geometry along a plane.
  • Cloth Create Seam
    Creates point attributes that define how the ClothStitchConstraint DOP stitches together panels.
  • Cloth Match Panels
    Ensures that all cloth seams have the same number of points on both sides.
  • Cloth Match Seams
    Ensures that all cloth seams have the same number of points on both sides.
  • Cloth Refine
    Refines cloth panels by triangulating them.
  • Color
    Adds color attributes to geometry.
  • Comb
    Adjust surface point normals by painting.
  • Connectivity
    Creates an attribute with a unique value for each set of connected primitives or points.
  • Control
    Creates simple geometry for use as control shapes.
  • Convert
    Converts geometry from one geometry type to another.
  • Convert Meta
    Polygonizes metaball geometry.
  • Cookie
    Combines two polygonal objects with boolean operators, or computes the contour line along the intersection between two polygonal objects.
  • Copy
    Creates multiple copies of the input geometry, or copies the geometry onto the points of the second input.
  • Crease
    Manually adds or removes a creaseweight attribute to/from polygon edges, for use with the Subdivide SOP.
  • Creep
    Deforms and animates a piece of geometry across a surface.
  • Curve
    Creates polygonal, NURBS, or Bezier curves.
  • Curveclay
    Deforms a spline surface by reshaping a curve on the surface.
  • Curvesect
    Finds the intersections (or points of minimum distance) between two or more curves or faces.
  • Deform
    Uses capture attributes created by Capture or Capture Proximity to deform outer geometry according to the movement of capture regions.
  • Deform Metaball
    Deforms captured points according to metaball deformations.
  • Deform Muscle
    Deforms captured points according to muscle deformations.
  • Delete
    Deletes input geometry by entity number, bounding volume, primitive/point normals, and/or degeneracy.
  • Dissolve
    Deletes points, primitives, and edges from the input geometry and repairs any holes left behind.
  • Divide
    Divides, smoothes, and triangulates polygons.
  • Dop I/O
    Imports fields from DOP simulations, saves them to disk, and loads them back again.
  • Dop Import
    Imports and transforms geometry based on information extracted from a DOP simulation.
  • Dop Import Fields
    Imports scalar and vector fields from a DOP simulation.
  • Duplicate
    Copies geometry and applies transformations to the copies.
  • Each
    Culls the input geometry in according to the specifications of the For Each SOP.
  • Edge Collapse
    Collapses edges and faces to their centerpoints.
  • Edge Cusp
    Sharpens edges by uniquing their points and recomputing point normals.
  • Edge Divide
    Inserts points on the edges of polygons and optionally connects them.
  • Edge Flip
    Flips the direction of polygon edges.
  • Edit
    Edits points, edges, or faces interactively.
  • Ends
    Closes, opens, or clamps end points.
  • Extrude
    Extrudes geometry along a normal.
  • Extrude Volume
    Extrudes surface geometry into a volume.
  • Facet
    Controls the smoothness of faceting of a surface.
  • File
    Reads, writes, or caches geometry on disk.
  • Fillet
    Creates smooth bridging geometry between two curves or surfaces.
  • Finalize Waves
    Imparts wave velocities to points in waveform geometry
  • Fit
    Fits a spline curve to points, or a spline surface to a mesh of points.
  • Font
    Creates 3D text from Type 1 and TrueType fonts.
  • ForEach
    Repeatedly applies a set of SOPs to the input geometry.
  • Force
    Uses a metaball to attract or repel particles or springs.
  • Fractal
    Creates jagged mountain-like divisions of the input geometry.
  • Fur
    Creates a set of hair-like curves across a surface.
  • Fuse
    Merges or splits (uniques) points.
  • Geometry ROP output driver
  • Grid
    Creates a plane.
  • Group
    Generates groups of points or primitives according to various criteria.
  • Group Copy
    Copies groups between two pieces of geometry, based on point/primitive numbers.
  • Group Paint
    Sets group membership interactively by painting.
  • Group Transfer
    Transfers groups between two pieces of geometry, based on proximity.
  • Hole
    Makes holes in surfaces.
  • Inflate
    Deforms the points in the first input to make room for the inflation tool.
  • Iso Offset
    Builds an offset surface from geometry.
  • Iso Surface
    Generates an isometric surface from an implicit function.
  • Join
    The Join op connects a sequence of faces or surfaces into a single primitive that inherits their attributes.
  • Knife
    Divides, deletes, or groups geometry based on an interactively drawn line.
  • L-system
    Creates fractal geometry from the recursive application of simple rules.
  • LOD
    Lets you view different levels of detail of geometry based on distance from camera.
  • Lattice
    Deforms geometry based on how you reshape control geometry.
  • Layer
    Lets you maintain multiple layers of attributes.
  • Line
    Creates polygon or NURBS lines from a position, direction, and distance.
  • MDD
    Animates points using an MDD file.
  • Magnet
    Deforms geometry by using another piece of geometry to attract or repel points.
  • Match Axis
    Aligns the input geometry to a specific axis.
  • Match Size
    Resizes and recenters the geometry according to reference geometry.
  • Match Topology
    Reorders the primitive and point numbers of the input geometry to match some reference geometry.
  • Material
    Assigns one or more materials to geometry.
  • Measure
    Measures volume, area, and perimeter of polygons and puts the results in attributes.
  • Merge
    Merges geometry from its inputs.
  • MetaGroups
    Defines groupings of metaballs so that separate groupings are treated as separate surfaces when merged.
  • Metaball
    Creates metaballs and meta-superquadric surfaces.
  • Mirror
    Duplicates and mirrors geometry across a mirror plane.
  • Mountain
    Displaces points along their normals based on fractal noise.
  • Muscle
    Support node for the Muscle object.
  • Name
    Creates a “naming” attribute on points or primitives allowing you to refer to them easily, similar to groups.
  • Network
    Transmits geometry data between two instances of Houdini over a network connection.
  • Null
    Does nothing.
  • Object Merge
    Merges geometry from other Geometry objects into this one.
  • POP Merge
    Loads the geometry from a pop network back into this Geometry object as points.
  • POP Network
    Contains a Particle node network.
  • Paint
    Lets you paint color or other attributes on geometry.
  • Particle
    Creates simple particle simulations without requiring an entire particle network.
  • Particle Fluid Surface
    Generates a polygonal surface around the particles from a particle fluid simulation.
  • Partition
    Places points and primitives into groups based on a user-supplied rule.
  • Paste
    Lets you paste local refinements on top of base NURBS geometry.
  • Peak
    Moves primitives, points, edges or breakpoints along their normals.
  • Platonic Solids
    Creates platonic solids of different types.
  • Point
    Manually adds or edits point attributes.
  • Point Cloud Iso Surface
    Constructs an iso surface from its input points.
  • Point Jitter
    Jitters points in random directions.
  • Pointmap
    A VEX node that generate points based on the luminance of a texture map.
  • Points From Volume
    Creates set of regular points filling a volume.
  • Poly Bevel
    Bevels points and edges.
  • Poly Cap
    Fills in polygons between boundary edges.
  • Poly Extrude
    Extrudes polygonal faces and edges.
  • Poly Frame
    Creates coordinate frame attributes for points and vertices.
  • Poly Knit
    Creates new polygons to joining existing polygons.
  • Poly Loft
    Creates new polygons using existing points.
  • Poly Patch
    Creates a smooth polygonal patch from primitives.
  • Poly Reduce
    Reduces the number of polygons in a model while attempting to preserve its shape.
  • Poly Spline
    The Polyspline op fits a spline curve to a polygon or hull and outputs a polygonal approximation of that spline.
  • Poly Split
    Divides an existing polygon into multiple new polygons.
  • Poly Stitch
    Stitches polygonal surfaces together, attempting to remove cracks.
  • Poly Wire
    Constructs polygonal tubes around polylines, creating renderable geometry with smooth bends and intersections.
  • Primitive
    Edits primitive, primitive attributes, and profile curves.
  • Primitive Split
    Takes a primitive attribute and splits any points whose primitives differ by more than a specified tolerance at that attribute.
  • Profile
    Extracts or manipulates profile curves.
  • Project
    Creates profile curves on surfaces.
  • RMan Shader
    Attaches RenderMan shaders to groups of faces.
  • Rails
    Generates surfaces by stretching cross-sections between two guide rails.
  • Ray
    Projects one surface onto another.
  • Refine
    Increases the number of points/CVs in a curve or surface without changing its shape.
  • Resample
    Resamples one or more curves or surfaces into even length segments.
  • Rest Position
    Sets the alignment of solid textures to the geometry so the texture stays put on the surface as it deforms.
  • Reverse
    Reverses or cycles the vertex order of faces.
  • Revolve
    Revolves a curve around a center axis to sweep out a surface.
  • Ripple
    Generates ripples by displacing points along the up direction specified.
  • Round
    Generates round fillets of a specified radius between two surfaces.
  • Scatter
    Scatters new points randomly across a surface.
  • Script
    Runs scripts when cooked.
  • Sculpt
    Lets you interactively reshape a surface by brushing.
  • Sequence Blend
    Sequence Blend lets you do 3D Metamorphosis between shapes and Interpolate point position, colors…
  • Shader
    Applies shaders to faces.
  • Shatter
    Shatters the input geometry by inducing multiple fracture lines in it.
  • Skin
    Builds a skin surface between any number of shape curves.
  • Slide Modifier Paint
    Lets you paint the slide modifier and inflation modifier attributes onto geometry interactively.
  • Smooth
    Smooths out (or “relaxes”) polygons, meshes and curves without increasing the number of points.
  • Soft Peak
    Moves the selected point along its normal, with smooth rolloff to surrounding points.
  • Soft Transform
    Moves the selected point, with smooth rolloff to surrounding points.
  • Sort
    Reorders points and primitives in different ways.
  • Sphere
    Creates a sphere or ovoid surface.
  • Spring
    Simulates the behavior of points as if the edges connecting them were springs.
  • Standard Variables
  • Starburst
    Insets points on polygonal faces.
  • Stitch
    Stretches two curves or surfaces to cover a smooth area.
  • Subdivide
    Subdivides polygons into smoother, higher-resolution polygons.
  • Subnetwork
    The Sub-net op is essentially a way of creating a macro to represent a collection of ops as a sin…
  • Super Quad
    Generates an isoquadric surface.
  • Surfsect
    Trims or creates profile curves along the intersection lines between NURBS or bezier surfaces.
  • Sweep
    Creates a surface by sweeping cross-sections along a backbone curve.
  • Switch
    Switches between network branches based on an expression or keyframe animation.
  • TimeBlend
    Blends intraframe values for geometry.
  • TimeShift
    Cooks the input at a different time.
  • TimeWarp
    Retimes the input to a different time range.
  • Torus
    Creates a torus (doughnut) shaped surface.
  • Trace
    Traces curves from an image file.
  • Trail
    Creates trails behind points.
  • Transform
    The Transform operation transforms the source geometry in “object space” using a transformation matrix.
  • Transform Axis
    Transforms the input geometry relative to a specific axis.
  • Tri Bezier
    Creates a triangular Bezier surface.
  • Tri Divide
    Refines triangular meshes using various metrics.
  • Tri Strip
    Converts polygons to triangle strips.
  • Triangulate 2D
    Connects points to form well-shaped triangles.
  • Trim
    Trims away parts of a spline surface defined by a profile curve or untrims previous trims.
  • Tube
    Creates open or closed tubes, cones, or pyramids.
  • Twist
    Applies deformations such as bend, linear taper, shear, squash/stretch, taper, and twist.
  • UV Brush
    Adjusts texture coordinates in the UV viewport by painting.
  • UV Edit
    Lets you interactively move UVs in the texture view.
  • UV Fuse
    Merges UVs.
  • UV Pelt
    Relaxes UVs by pulling them out toward the edges of the texture area.
  • UV Project
    Assigns UVs by projecting them onto the surface from a set direction.
  • UV Quick Shade
    Applies an image file as a textured shader to a surface.
  • UV Texture
    Assigns texture UV coordinates to geometry for use in texture and bump mapping.
  • UV Transform
    Transforms UV texture coordinates on the source geometry.
  • UV Unwrap
    Separates UVs into reasonably flat, non-overlapping groups.
  • Unix
    Processes geometry using an external program.
  • Unpaste
    The Unpaste op removes one or more pasted surfaces from a paste hierarchy, causing the hierarchy to update.
  • VEX SOP
    References a VEX program that can manipulate point attributes.
  • VOP SOP
    Contains a VOP network that can manipulate point attributes.
  • Vertex
    Manually adds or edits attributes on vertices (rather than on points).
  • Vertex Split
    Takes a vertex attribute and splits any point whose vertices differ by more than a specified tolerance at that attribute.
  • Visibility
    Shows/hides primitives in the 3D viewer and UV editor.
  • Volume
    Creates a volume primitive.
  • Volume Break
    Breaks geometry using a signed distance field volume.
  • Volume Mix
    Combines the scalar fields of volume primitives.
  • Volume Ramp
    Remaps a volume according to a ramp.
  • Volume SDF
    Builds a Signed Distance Field from an isocontour of a volume.
  • Volume Splice
    Splices overlapping volume primitives together.
  • Volume Vop
    Runs CVEX on a set of volume primitives.
  • Vortex Force Attributes
    Creates the point attributes needed to create a Vortex Force DOP.
  • Waveform
    Creates a waveform shape out of surface geometry
  • Wire Blend
    Morphs between curve shapes while maintaining curve length.
  • Wire Capture
    Captures surfaces to a wire, allowing you to edit the wire to deform the surface.
  • Wire Deform
    Deforms geometry captured to a curve via the Wire Capture node.
  • Wire Transfer Shape
    Transfers the shape of one curve to another.
  • Wireframe
    Constructs polygonal tubes around polylines, creating renderable geometry.