Houdini 20.0 Nodes Geometry nodes

Fuse geometry node

Merges or splits (uniques) points.

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The Fuse SOP is used to snap points together, make the points unique, or snap points to a 3d grid.

You can consolidate points based on their proximity to each other (given by the distance threshold) or you can have all the points in the given group be consolidated to the first point of that group. This option is commonly used in a procedural fashion to clean up models that may have unshared edges that need to be removed. This is necessary to have certain surfaces subdivide properly. Generally the entire geometry set (empty Group field) or large parts of the geometry are procedurally processed in this method.

To consolidate all points in the group to the first point in the Group point list, turn off the distance field.

Tip

When fusing multiple line primitives into a single line, they will still maintain separate primitives. If you wish to make the result into a single primitive, append the Join SOP with Only Connected enabled.

You can snap points based on their proximity to each other (given by the distance threshold) but no consolidation is done. The snap option has more options on the actual snap behavior. This method is commonly used on a small selection of points in classic modeling operations.

Snapping to a grid is useful for grabbing points and ordering them to a 3d grid. This method is commonly used on individual point selections in classic modeling operations. Snapping to a grid is also useful when outputting to low res consoles as you can truncate vertices to lie on a certain integer boundaries globally on the model.

Using Fuse

  1. Select the points you want to merge.

  2. Click the Fuse tool on the Polygon tab.

The merge is based on the proximity of the points to each other. The threshold distance for consolidation can be modified in the parameter editor.

Parameters

Group

Subset of points to unique or consolidate.

Update Point Normals

Recomputes point normals, if they exist.

Use Accurate Distance

Forces Distance to represent consolidate or snap distances accurately, and forces consolidation or snapping to be performed in order of point number, (reverse for snapping to highest point number), to avoid moving points to within Distance of other points. That issue may still occur for snapping to average value, as no snap order can then guarantee that points aren’t moved to within Distance of other points.

Consolidate

Overview

Points within a specified distance of each other will share a point.

Distance

Threshold distance for consolidation.

Remove Degenerate Primitives

Cleans up any degenerate polygons.

Keep Unused Points

Keeps any points that were not part of a primitive before the fuse and, if Remove Degenerate Primitives is set, any points orphaned by removing degenerate polygons.

Keep Consolidated Points

Keeps any points that are orphaned and not part of any polygons because they have been consolidated.

Group Propagation

This lets you specify how the fused points get assigned to the Point Groups from the original points.

Least Point Number

The fused point will belong to same groups that the original point with the least point number belongs to. This is the fastest method.

Union

The fused point will belong to any group that contains at least one of the original points. For example, if two original points are fused and one of them belongs to Group A and the other belongs to Group B, the fused point will belong to Groups A and B. In other words, the fused point will belong to the union of the groups of the original points.

Intersect

The fused point will belong to the groups that contain all of the original points. As an example, if two original points are fused and one belongs to Groups A and B while the other belongs to Groups B and C, the fused point will belong to Group B. In this case, the fused point will belong to the intersection of the groups of the original points.

Unique

Makes each vertex a unique point.

Snap

Overview

Point positions and/or point attributes only will be altered.

Distance/Grid

How to do the snapping. Internal will snap points to other points in the same object. Grid will snap to user specified grid lines.

Distance

Snap Type

What heuristic to use to determine the position or attribute values of snapped points. It can be the average of all the points to be snapped. Or, it can snap to the least or greatest point number, which is useful if you know one of those is the real value.

Snap Distance

The maximum distance to snap points together

Snap Point Positions

Moves the point positions according to the Snap Type. If this is turned off, the point positions will not be changed. This is mainly useful if you enable Snap Point Attributes and only want to snap together the point attributes.

Snap Point Attributes

Snaps together the point attribute values of the snapped points. The values are set according to the Snap Type, so the new attribute values can be an average, or taken from the point with the least or greatest point number.

Point Attributes

Select the point attributes that you want to snap together. If you set Snap Type to “Average”, you can only snap floating point-, vector- or integer- valued attributes.

Grid

Grid Type

How to specify the grid size.

Grid Spacing

The number of units between each grid line

Grid Lines

The number of grid lines every unit

Grid Power 2

The same as gridlines, but a power of two is specified. This means a value of 7 means 128, and 9 means 512.

Grid Offset

A number from 0 to 1 which specifies what offset the grid should have from (0,0,0).

Grid Rounding

Which way points should snap to the grid.

Grid Tolerance

Maximum distance to move points to grid

See also

Geometry nodes