Houdini 20.5 Nodes Geometry nodes

PolySplit 2.0 geometry node

Divides an existing polygon into multiple new polygons.

On this page
Since 15.5

Overview

PolySplit has two different modes of operation, controlled by the Path type parameter. The two modes have their own tools on the Polygon shelf:

Inserting individual new edges into existing polygons. You can insert a chain of cuts (possibly self-intersecting) across multiple polygons. You can insert cuts between polygons without shared edges.

Inserting edge loops.

This node preserves vertex and primitive attributes as well as group memberships on newly created polygons.

How to

To...Do this

Insert a new edge

  1. Select the polygonal surface you want to edit.

  2. On the Polygon shelf tab, click the PolySplit tool.

  3. Click to insert new points.

    Drag along an edge to snap a point to the edge. (You can press ⌃ Ctrl and move off the edge to escape the snapping.)

  4. Press Enter to finish inserting edges.

When you finish inserting points, the tool will insert edges along the shortest path between each point. You can click ⇧ Shift + in the tool to edit the points again.

Insert an edge loop

  1. Select the polygonal surface you want to edit.

  2. On the Polygon shelf tab, click the Edge Loop tool.

  3. Click an edge to insert an edge loop at that point.

Insert multiple edge loops at regular intervals

  1. Select the polygonal surface you want to edit.

  2. On the Polygon shelf tab, click the Edge Loop tool.

  3. In the parameters, change the Number of loops.

  4. Click an edge to insert regularly spaced edge loops along the edge.

Tips

  • The Edge Loop tool on the shelf just inserts a PolySplit with Path type automatically set to “Edge Loop”.

  • Turn on Edge snap in the toolbar at the top of the view, or click , to turn on snapping to edge divisions. Change the Divisions in the toolbar or use the MOUSE_WHEEL mouse wheel to change the number of divisions.

    You can increase the number of divisions up to 10 with the MOUSE_WHEEL mouse wheel. To get more than 10 divisions, enter the number in the Divisions box on the operation toolbar.

  • You can insert a “cut” between the ends of an open polygon to close the polygon.

  • You can only insert new points in the interior of a polygon if the polygon is closed.

Parameters

Split Locations

The chain of locations along which to make cuts, using the following codes.

‹a›v‹b›

Cut at vertex ‹b› of primitive ‹a›, where ‹a› and ‹b› are integers.

‹a›e‹b›

Cut at the midpoint of edge ‹b› of primitive ‹a›, where ‹a› and ‹b› are integers.

‹a›e‹b›:‹t›

Cut at ‹t› percent along edge ‹b› of primitive ‹a›, where ‹a› and ‹b› are integers and ‹t› is a real number from 0.0 to 1.0.

‹a›f:‹u›,‹v›

Cut at the given (u,v) location on primitive ‹a›, where ‹a› is an integer and ‹u› and ‹v› are real numbers from 0.0 to 1.0.

p‹a›-‹b›

Cut at the midpoint of the edge between points ‹a› and ‹b›, where ‹a› and ‹b› are integers.

p‹a›-‹b›:‹t›

Cut at ‹t› percent along the edge between points ‹a› and ‹b›, where ‹a› and ‹b› are integers and ‹t› is a real number from 0.0 to 1.0.

Path Type

Whether to insert edges along the shortest path between cut points, or insert edge loops.

Close Path

Causes an extra cut to be made from the last split location to the first.

Allow split points on faces

By default, the node lets you insert points in the interior of existing faces, to cut pieces out of the faces, producing N-sided polygons. To prevent accidental creation of these kinds of cuts, turn this parameter off. This will only allow insertion of points on edges.

Quad autocompletion

Inserts an extra cut to produce quads in two common cases where a split across the corner of a quad would create an N-sided polygon.

In the following illustration, the red dotted lines are new edges that Quad autocompletion will automatically insert if you make the yellow cuts, to prevent the larger area from becoming an N-sided polygon.

These are the only cases where this option will insert extra cuts.

Number of loops

When Path type is “Edge Loop”, the number of evenly spaced edge loops to insert along the selected edges.

Match Profile

Causes the edge loop to cross each edge at a fixed distance along it’s length instead of a percentage.

Switch Profile

Causes the edge loop to measure the fixed distance from the other side of each edge it crosses. If Match Profile is off, this option is ignored.

Edge percentage

Turn this parameter on and set a value from 0-1 to specify exactly the positions of all cut points. For example, setting this to 0.5 will lock all cut points to the midpoint of each edge. This is useful for making exact straight or diagonal cuts.

Update Point Normals

Update point normals if they exist.

Edge group

When Create edge group is on, the node will put new edges it creates into this group.

Append to group

Put any new edges created by this node into an edge group with the name specified in Path edge group below.

Tolerance

If you are working at very small scales, or if this node generates bad geometry where the split path is very close to corners, you can try decreasing the tolerance.

Examples

PolySplitHood Example for PolySplit geometry node

This example shows how to use the PolySplit SOP to refine the geometry of a car hood by splitting polygons.

See also

Geometry nodes