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.

Nodes

	Add	Creates Points or Polygons, or adds points/polys to an input.
	Alembic	Loads the geometry from an Alembic scene archive (.abc) file into a geometry network.
	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 Cast	Changes the size/precision Houdini uses to store an attribute.
	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.
	Attribute Fade	Fades a point attribute in and out over time.
	Attribute From Map	Samples texture map information to a point attribute.
	Attribute From Volume	Copies information from a volume onto the point attributes of another piece of geometry, with optional remapping.
	Bake ODE	Converts primitives for ODE and Bullet solvers.
	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.
	Bone Link	Creates default geometry for Bone objects.
	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 Capture	Captures low-res simulated cloth.
	Cloth Deform	Deforms geometry captured by the Cloth Capture SOP.
	Cloth Refine	Refines cloth panels by triangulating them.
	Cluster	Low-level machinery to cluster points based on their positions (or any vector attribute).
	Cluster Points	Higher-level node to cluster points based on their positions (or any vector attribute).
	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.
	Convert volume	Polygonizes volume 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.
	DOP Import Records	Imports option and record data from DOP simulations into points with point attributes.
	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 group, entity number, bounding volume, primitive/point normals, and/or degeneracy.
	Delete Overlapping Polygons	Removes polygons that overlap.
	Dissolve	Deletes points, primitives, and edges from the input geometry and repairs any holes left behind.
	Divide	Divides, smooths, 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.
	Exploded View	Pushes geometry out from the center to create an exploded view.
	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.
	File Merge	Reads and collates data from 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.
	Fluid Source	Creates one or multiple volumes out of geometry to be used in a fluid simulation
	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
	Glue Cluster	Adds strength to a glue constraint network according to cluster values.
	Glue Pieces	Creates a glue constraint network between adjacent pieces.
	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.
	Load Slices	Reads and collates distributed data from disk.
	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.
	Particle Fluid Tank	Creates a set of regular points filling a tank.
	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.
	PolyDoctor	Helps repair invalid polygonal geometry, such as for cloth simulation.
	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 or through a volume.
	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.
	Shrink Wrap	Takes the convex hull of input geometry and moves its polygons inwards along their normals.
	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.
	Solver	Allows running a SOP network iteratively over some input geometry, with the output of the network from the previous frame serving as the input for the network at the current frame.
	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 Subnet 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.
	Table Import	Reads a CSV file creating point per row.
	Tetrahedralize	Connects points into a Delaunay Tetrahedralization.
	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 Analysis	Computes analytic properties of volumes.
	Volume Blur	Blurs the voxels of a volume.
	Volume Break	Cuts polygonal objects using a signed distance field volume.
	Volume Compress	Re-compresses Volume Primitives.
	Volume Feather	Feathers the edges of volumes.
	Volume From Attrib	Sets the voxels of a volume from point attributes.
	Volume Merge	Flattens many volumes into one volume.
	Volume Mix	Combines the scalar fields of volume primitives.
	Volume Ramp	Remaps a volume according to a ramp.
	Volume Reduce	Reduces the values of a volume into a single number.
	Volume Resample	Resamples the voxels of a volume to a new resolution.
	Volume SDF	Builds a Signed Distance Field from an isocontour of a volume.
	Volume Slice	Extracts 2d slices from volumes.
	Volume Splice	Splices overlapping volume primitives together.
	Volume Surface	Adaptively surfaces a volume hierarchy with a regular triangle mesh.
	Volume Trail	Computes a trail of points through a velocity volume.
	Volume Velocity	Computes a velocity volume.
	Volume Visualization	Adjusts attributes for multi-volume visualization.
	Volume Vop	Runs CVEX on a set of volume primitives.
	Volume bounds	Bounds voxel data.
	Voronoi Fracture	Fractures the input geometry by performing a Voronoi decomposition of space around the input cell points
	Voronoi Fracture Points	Given an object and points of impact on the object, this SOP generates a set of points that can be used as input to the Voronoi Fracture SOP to simulate fracturing the object from those impacts.
	Voronoi Split	Cuts the geometry into small pieces according to a set of cuts defined by polylines.
	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.

Nodes Surface nodes

Overview

Surface node flags

Unload flag

Nodes

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