Houdini 20.5 Nodes Geometry nodes

Convert geometry node

Converts geometry from one geometry type to another.

On this page

Using Convert

  1. Select the primitive to convert.

  2. Click the Convert tool on the Model tab.

  3. Choose the geometry type in the Convert To drop-down menu on the operation controls toolbar or the parameter editor.

Face to Surface Conversion

When converting from a set of polygons to a mesh, a single mesh will result only if:

  • more than one polygon is in the input, and

  • each polygon has exactly four points, and

  • the polygons are arranged as n rows by n columns

  • the polygons share coincident points (see Facet OP)

Otherwise, each polygon is converted individually into a mesh. In fact, any individual face can be converted to any surface. This is accomplished by cutting the face into three or four adjacent sections, and then creating a patch from them.

Parameters

Group

Subset of primitives to convert.

From Type

Which geometry types will be converted.

Convert To

What the geometry will be converted to.

Connectivity

Method of surface construction.

Level of Detail

Overview

Use a floating point level of detail to determine conversion resolution. A value of 1 will divide once per voxel.

U

Point density in U direction.

V

Point density in V direction.

Trim-Curve

Point density for the trim curves.

Divisions

Overview

Exact number of points to be computed within each span.

U

Point count in U direction.

V

Point count in V direction.

Trim-Curve

Point count for the trim curves.

U Order

Spline order of curves & surfaces in U.

V Order

Spline order of curves & surfaces in V.

Paste Coordinates

Evaluate base or feature surface for position.

Paste Attributes

Evaluate base or feature surface for attributes.

Preserve Original

Retains original geometry along with converted geometry.

Interpolate Through Hulls

Splines will preserve the shape of the geometry they are converted from. Otherwise, points in the geometry are used as points in the hull.

Volume Offset

When converting volumes to polygons, this is the value of the isosurface that will be extracted. 0 works for Signed Distance Fields. 0.5 might work better for a fog volume.

Note: For faster conversion of volumes, consider using the specialized Convert Volume.

Examples

ConvToTrimSurface Example for Convert geometry node

This example shows how to create a trimmed NURBS or Bezier surface using the Convert SOP.

There are four examples contained that compare how a trimmed surface handles a texture.

  • Grid Surface a simple texture map on a grid.

  • Trimmed Circle Using the Trim SOP the conventional way of creating a trimmed surface using a Project SOP and a Trim SOP.

  • Trimmed Circle Using the Convert SOP creates a trimmed surface using a Convert SOP.

  • NURBS Surface Using the Convert SOP shows how a texture is parametrized over a surface that is not trimmed.

To get a better sense of the parameterization of the texture, turn on points and toggle between wireframe and shaded modes.

ConvertBasic Example for Convert geometry node

This example shows the various ways in which the Convert SOP converts geometry types using a simple sphere.

A chart is used for this demonstration.

The left column of the chart describes the original geometry type to convert from.

The top row of the chart describes the geometry type to convert to.

All Sphere SOPs and Convert SOPs in this demonstration use their default values to better visualize the differences.

CurveToPrimCircle Example for Convert geometry node

This example is a simple demonstration on how to convert a curve into a primitive circle.

To convert a NURBS or Bezier closed curve to a primitive circle, it must first be converted to a polygon.

Once converted to a closed polygon curve, you can convert the curve to a primitive circle.

Potatochip Example for Convert geometry node

This example demonstrates how to convert a closed curve into a surface using the Convert SOP.

There are two versions contained in this example. One curve has been successfully converted to a surface, the other has not because of the concave shape of the original curve.

View in shaded mode to get a better sense of this.

See also

Geometry nodes