Houdini 20.0 Nodes Geometry nodes

RBD Material Fracture 3.0 geometry node

Fractures the input geometry based on a material type.

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Since 18.0

Overview

This node allows you to accurately fracture geometry based on a specific type of material. Currently concrete, glass panels, and wood are supported.

It accepts four inputs: geometry, constraint geometry, proxy geometry, and an optional input for extra points to control the fracturing process. It will fracture the incoming geometry using different fracturing method depending on the material specified in the Material Type parameter. If an input constraint geometry is specified, it will update the constraints for the fractured pieces.

See fracturing objects for simulation for a guide to fracturing workflows and tools in Houdini.

Using different displays

The Guide Geometry parameter on the RBD Material Fracture node will allow you to switch between different displays. All materials have Fractured Geometry, which will display the group being fractured.

They also all have Constraint Network, which will display the internal constraint network of all fractured pieces.

There are two concrete-specific displays: Primary Volume and Edge Detail. These views allow you to display the volume distribution for each primary fracture level used for scattering and display the boolean cutting planes used to generate the edge detail.

There are also two glass-specific displays: Concentric Noise and Edge Detail. These views allow you to display the noise used for determining the discontinuity for concentric cracks and display the magnitude distribution of the edge noise.

The three wood-specific displays allow you to display the cutting planes for grains, cuts, and splinters.

There are three custom-specific displays: Primary Volume, Cutter Geometry and Boolean Guide. These views allow you to display the volume distribution for the built-in scattered cutter geometry, display the cutter geometry, and the cutter geometry with the edge detail noise.

Parameters

Group

The geometry to be fractured. If no group is specified, the full input geometry will be fractured.

Material Type

The type of material of the incoming geometry.

Concrete

Concrete material type.

Glass

Glass material type. Choose between Flat Panes or Curved Glass.

Wood

Wood material type.

Custom

Custom cutters.

Fracture Namespace

Adds a namespace prefix to the name of each piece. This is useful for avoiding duplicate piece names or isolating a group of constraints.

Fracture per Piece

Loops through each piece in the input geometry and fractures them individually. If the Piece Attribute is not found, it will fracture based on connectivity.

Piece Attribute

The primitive attribute that defines each piece for partitioning.

Single Pass

Fractures a specific piece at the given index. This can be useful for debugging and testing using a single piece.

Random Seed

The seed used when adding random variation of the parameters for each piece.

Piece Prefix

The prefix applied to the name of each piece created by the fracture.

- will create pieces such as piece0-0-0, piece0-0-1, etc

_ will result in piece0_0_0, piece0_0_1 etc

Reset Cached Pass

Resets the currently cached display in the for loop. Use this to update the guide geometry if it is not displaying the current geometry.

Concrete

Guide Geometry

None

No guide geometry.

Fractured Geometry

The group that is currently being fractured will be highlighted.

Primary Volume

Displays the volume distribution for each primary fracture level used for scattering.

Edge Detail

Displays the cutting planes used to generate the edge detail.

Constraint Network

Displays the constraint network of all pieces.

Primary Fracture

Enable Fracture

Turning off this checkbox will bypass this fracture level.

Fracture Level

The number of levels of recursive fracturing to perform.

Fracture ID

The fracture ID for this fracture level. The output attributes and groups associated with this fracture level will have this tag.

Fracture Ratio

The ratio of all the pieces from the previous level to fracture at this level.

Fracture Seed

The random seed to determine which pieces will or won’t be fractured when fracture ratio is lower than 1.

Connectivity Partition

None

Do not further partition pieces into groups by connectivity.

Overwrite Piece Numbering

Turning on this option will further divide the pieces into separate, connected groups of geometry. Normally each input cell point will create one output piece. However, with concave objects this can mean that disconnected pieces of geometry are placed in the same piece. This option allows the piece numbers to be overwritten by this operation, which is fast and acceptable if you don’t need the piece numbers to match the input point numbers.

Cell Points

Scatter From

Volume

Scatters points based on the fog volume generated.

Attribute

Scatters points based on the specified point attribute in the incoming geometry. For example, the RBD Paint SOP can be used to paint a density attribute on the geometry.

Attribute Name

The name of the point attribute to use as a density attribute when scattering points.

Scatter Points

The number of points to scatter.

Scatter Points Scaling

None

Do not affect the number of scattered points.

Scale by Piece Volume

Multiplies the number of scattered points by the piece’s volume.

Note

This is only available with the Concrete material.

Large pieces can generate a lot more points. Use the Remap Range option for better control over the total number of points being generated.

Scale by Max Axis Length

Multiplies the number of scattered points by the piece’s bounding box’s maximum axis length.

Note

This is only available with the Concrete material.

Large pieces can generate a lot more points. Use the Remap Range option for better control over the total number of points being generated.

Scale by Attribute

Multiplies the number of scattered points by the average value across the piece of the given attribute.

Remap Range

Enables fitting the range of the piece’s volume or max axis length value to a min and max range.

Values outside the input range will be clamped to the input range.

Input Min/Max

Specifies the input’s minimum and maximum values.

Output Min/Max

Specifies the output’s minimum and maximum values.

Scatter Points Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Scatter Seed

The random seed for scattering points.

Use Input Points

Use points from the fourth input.

Note

If a name attribute exists on the points, only points with a matching name will be used for the piece being fractured.

Wildcards are supported.

Input Points

The group of points from the fourth input to use.

Fog Volume

Noise Type

The type of noise. Select from None, Perlin Noise, Original Perlin Noise, Sparse Convolution Noise, Alligator Noise, Simplex Noise and Zero Centered Perlin.

Volume Resolution

The resolution of the fog volume. The higher the resolution, the slower the fracturing time will be. Smaller geometry will require higher volume resolution.

Noise Frequency

The frequency of the noise. Higher values give smaller scaled details in the noise.

Noise Offset

The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.

Cutoff Density

The low density level to cutoff at. Density below this value will be discarded.

Chipping

Enable Chipping

Break off corners of pieces to create chips.

Chipping Ratio

The overall ratio out of all the pieces to perform chipping on.

Seed

The overall seed for the ratio of chipping.

Randomness

Randomizes the chipping ratio for each piece by this amount, when fracturing per piece.

Corner Ratio

The ratio of corner points to use to generate chipping cutting planes.

Corner Depth

A normalized distance from corner to the center of the piece where the chipping plane will be instantiated.

Directional Noise

Amount of noise to add to the corner normal to align the cutting plane to.

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Detail

Detail Size

The size of the polygons added for the edge and interior detail.

Edge Detail

Use Boolean to obtain edge detail.

Noise Height

Scales the amount of displacement.

Noise Element Size

The size of the noise pattern. Higher values give larger scaled details in the noise.

Lacunarity

An increment for the noise element size between fracture iterations.

Note

This parameter has no effect on the first fracture iteration.

Level Multiplier

An increment for the noise height between fracture iterations.

Note

This parameter has no effect on the first fracture iteration.

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Interior Detail

Adds noise to the interior points, scaled based on their distance to the surface.

Noise Amplitude

Scales the amount of displacement.

Noise Type

The type of noise added to the interior points.

Frequency

The frequency of the noise. Higher values give smaller scaled details in the noise.

Offset

The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.

Crease Weights

Creases control the strength of pull of the polygon faces on the subdivision surfaces, much like a magnet drawing the surface towards the reference polygon. When this is turned on, a creaseweights attribute will be created and the specified value will be applied to the vertices at the interface between the outside and inside faces. See the Subdivide SOP for more details.

Weight

Specify the creaseweights value.

Proxy Geometry

Default

Uses the default voronoi fractured geometry.

Convex Decomposition

Performs a convex decomposition from the fractured input geometry.

Packed Spheres

Uses packed sphere primitives from the fractured input geometry.

Max Concavity

The maximum distance from a point on the geometry to it’s closest convex hull edge. Reducing this value will produce convex hulls that are a closer fit to the input geometry, but the geometry may be split into more segments.

Voxel Size

The size of voxels in the output VDB volume. Surface features smaller than this will not be in the output VDB.

Min Radius in Voxels

Determines the smallest sphere size in voxel units.

Max Radius in Voxels

Determines the largest sphere size in voxel units.

Max Spheres

No more than this number of spheres are generated per VDB primitive.

Constraints

Search Radius

When re-wiring incoming constraints, specify the search radius within which to look for matching connections.

Use Tags

Creates a constraint_tag string attribute on the constraint primitives instead of using groups. This allows for more flexibility and matches the Vellum constraints.

Apply Constraint Properties

Applies constraint properties to the output constraint geometry. The RBD Constraint Properties SOP can be used for advanced constraint setups.

Glue Constraint Name

Specifies the Data Name of the constraint data (for example, the Glue Constraint Relationship) to use in the DOP network.

Enable Color

Adds a color to the various constraints being created for quick identification.

Primary Strength

The starting strength of the glue bonds of primary fracture.

Level Multiplier

The number to multiply the primary strength with for each increment of fracture level.

Chipping Strength

The strength of glue bonds for corner chips.

Strength Variance

Randomly varies the strength of each glue bond.

Switch to Soft Constraint when Broken

Specifies a different constraint type to switch to if the glue constraint is broken by the Bullet Solver.

Note

This parameter does not set attributes directly but determines which parameters are relevant to streamline the UI.

Soft Constraint Name

Specifies the Data Name of the constraint data (for example, the Bullet Soft Constraint Relationship) to use in the DOP network once the initial constraints are broken.

Degrees of Freedom

Specifies whether the constraint affects position, orientation, or both. This does not apply to glue constraints, which work by simulating glued chunks together as a single object with a compound collision shape.

Stiffness

Specifies the strength of the force that attempts to match the transforms of the two anchors.

This value is equivalent to the frequency of a spring.

Damping Ratio

Specifies how much damping is applied to the motion. A value of 0 specifies no damping, and a value of 1 provides just enough damping to prevent oscillation. Values between 0 and 1 allow oscillation (with some damping), and values greater than 1 provide increasingly damped motion that has no oscillation.

This value is equivalent to the damping ratio of a spring.

Glass

Mode

Flat Panes

When fracturing flat panes of glass, this option is faster than the Curved Glass option as it only performs sequential voronoi fractures for the radial cracks and the concentric cracks. When edge noise is enabled, it adds detail to the internal faces before applying the edge noise. While this is very efficient, it can introduce visible cracks between the pieces.

Curved Glass

Select this option when fracturing curved glass. When edge noise is enabled, boolean fracturing is performed on the high res geometry sequentially for the radial cracks followed by the concentric cracks. This is slower than the Flat Panes mode which applies noise after the fracturing is performed, however it doesn’t create visible cracks between the pieces.

Guide Geometry

None

No guide geometry.

Fractured Geometry

The group that is currently being fractured will be highlighted.

Concentric Noise

Displays the noise used for determining the discontinuity for concentric cracks.

Edge Noise

Displays the magnitude distribution of the edge noise.

Constraint Network

Displays the constraint network.

Impact Points

Use Scatter

Uses randomly scattered points on the surface as impact points.

Scatter Points

The number of points to scatter.

Scatter Points Scaling

None

Do not affect the number of scattered points.

Scale by Piece Volume

Multiplies the number of scattered points by the piece’s volume.

Note

This is only available with the Concrete material.

Large pieces can generate a lot more points. Use the Remap Range option for better control over the total number of points being generated.

Scale by Max Axis Length

Multiplies the number of scattered points by the piece’s bounding box’s maximum axis length.

Note

This is only available with the Concrete material.

Large pieces can generate a lot more points. Use the Remap Range option for better control over the total number of points being generated.

Scale by Attribute

Multiplies the number of scattered points by the average value across the piece of the given attribute.

Scatter Points Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Scatter Seed

The random seed for scattering points.

Use Input Points

Use points from the fourth input.

Note

If a name attribute exists on the points, only points with a matching name will be used for the piece being fractured.

Wildcards are supported.

Input Points

The group of points from the fourth input to use.

Cracks

Radial Crack

Radial Crack Number

The number of radial cracks to generate for each impact point.

Radial Crack Scaling

None

Do not affect the number of radial cracks.

Scale by Attribute

Multiplies the number of radial cracks by the average value across the piece of the given attribute.

Radial Crack Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Number Variance

The variance in the number of radial cracks for each piece.

Number Seed

The seed for the variance of the number of radial cracks.

Radial Fracture ID

The fracture ID for this fracture. The output attributes and groups associated with this fracture will have this tag.

Concentric Crack

Minimum Width

The minimum width between each concentric crack going outward radially.

Minimum Width Scaling

None

Do not affect the minimum width.

Scale by Attribute

Multiplies the minimum with by the average value across the piece of the given attribute.

Minimum Width Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Impact Spread

How far from the origin(s) the concentric cracks spread.

Discontinuity Freq

The frequency of the discontinuity noise for concentric cracks.

Discontinuity Size

The amplitude of the discontinuity noise for concentric cracks.

Concentric Fracture ID

The fracture ID for this fracture. The output attributes and groups associated with this fracture will have this tag.

Chipping

Enable Chipping

Break off corners of pieces to create chips.

Chipping Ratio

The overall ratio out of all the pieces to perform chipping on.

Seed

The overall seed for the ratio of chipping.

Randomness

Randomizes the chipping ratio for each piece by this amount, when fracturing per piece.

Corner Ratio

The ratio of corner points to use to generate chipping cutting planes.

Corner Depth

A normalized distance from corner to the center of the piece where the chipping plane will be instantiated.

Directional Noise

Amount of noise to add to the corner normal to align the cutting plane to.

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Detail

Detail Size

The size of the polygons to add for the edge noise.

Edge Noise

Enable Edge Noise

Adds noise to the cracks.

Fade From Origin

How far to fade off the edge noising from the fracture origins.

Fade From Border

How far to fade off the edge noising from the borders of the glass.

Noise Amplitude

Scales the amount of displacement.

Noise Frequency

The frequency of the noise. Higher values give smaller scaled details in the noise.

Note

Noise Amplitude and Noise Frequency can be driven via attributes on the mesh: amp (float) and freq (vector or float3) respectively.

Detriangulate

When Mode is set to Curved Glass,

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Proxy Geometry

Use Convex Decomposition

Creates proxy geometry from the high-resolution pieces using a convex decomposition.

Max Concavity

The maximum distance from a point on the geometry to it’s closest convex hull edge. Reducing this value will produce convex hulls that are a closer fit to the input geometry, but the geometry may be split into more segments.

Crease Weights

Creases control the strength of pull of the polygon faces on the subdivision surfaces, much like a magnet drawing the surface towards the reference polygon. When this is turned on, a creaseweights attribute will be created and the specified value will be applied to the vertices at the interface between the outside and inside faces. See the Subdivide SOP for more details.

Weight

Specify the creaseweights value.

Constraints

Search Radius

When re-wiring incoming constraints, specify the search radius within which to look for matching connections.

Use Tags

Creates a constraint_tag string attribute on the constraint primitives instead of using groups. This allows for more flexibility and matches the Vellum constraints.

Apply Constraint Properties

Applies constraint properties to the output constraint geometry. The RBD Constraint Properties SOP can be used for advanced constraint setups.

Glue Constraint Name

Specifies the Data Name of the constraint data (for example, the Glue Constraint Relationship) to use in the DOP network.

Enable Color

Adds a color to the various constraints being created for quick identification.

Radial Color

Specifies the color for the radial constraints.

Concentric Color

Specifies the color for the concentric constraints.

Radial Strength

The strength of the glue bonds between radial cracks.

Concentric Strength

The strength of the glue bonds between concentric cracks.

Chipping Strength

The strength of glue bonds for corner chips.

Strength Variance

Randomly varies the strength of each glue bond.

Switch to Soft Constraint when Broken

Specifies a different constraint type to switch to if the glue constraint is broken by the Bullet Solver.

Note

This parameter does not set attributes directly but determines which parameters are relevant to streamline the UI.

Soft Constraint Name

Specifies the Data Name of the constraint data (for example, the Bullet Soft Constraint Relationship) to use in the DOP network once the initial constraints are broken.

Degrees of Freedom

Specifies whether the constraint affects position, orientation, or both. This does not apply to glue constraints, which work by simulating glued chunks together as a single object with a compound collision shape.

Stiffness

Specifies the strength of the force that attempts to match the transforms of the two anchors.

This value is equivalent to the frequency of a spring.

Damping Ratio

Specifies how much damping is applied to the motion. A value of 0 specifies no damping, and a value of 1 provides just enough damping to prevent oscillation. Values between 0 and 1 allow oscillation (with some damping), and values greater than 1 provide increasingly damped motion that has no oscillation.

This value is equivalent to the damping ratio of a spring.

Wood

Guide Geometry

None

No guide geometry.

Fractured Geometry

The group that is currently being fractured will be highlighted.

Grains

Displays the cutting planes for the grains.

Cuts

Displays the cutting planes for the cuts.

Splinters

Displays the cutting planes for the splinters.

Constraint Network

Displays the constraint network.

Grain

Enable Grain

Creates grain lines along the Fracture Direction, which typically is the geometry’s longest axis.

Fracture Direction

Auto (Bounding Box)

Determines the direction automatically based on the oriented bounding box.

Vector

Uses the vector specified as the direction of fracturing.

Grain Spacing

The spacing between grain lines.

Grain Spacing Scaling

None

Do not affect the spacing.

Scale by Attribute

Divides the spacing by the average value across the piece of the given attribute. A smaller value will result in larger spacing.

Grain Spacing Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Grain Offset

The size of offset randomly applied to each grain line.

Grain Offset Seed

The seed of the random offset.

Grain Noise

Height

Displacement amount of the height.

Element Size

Distance between peaks of lowest frequency noise.

Grain Detail Size

The size of polygons used to cut the grain lines.

Grain Fracture ID

The fracture ID for this fracture. The output attributes and groups associated with this fracture will have this tag.

Cut

Enable Cut

Creates cuts in the opposite direction of the grain lines.

Fracture Direction

Auto (Bounding Box)

Determines the direction automatically based on the oriented bounding box.

Vector

Uses the vector specified as the direction of fracturing.

Skew Angle

Rotates the cutting plane along the axis perpendicular to the grain cut direction, when Fracture Direction is set to Auto.

Cut Spacing

The spacing between cuts.

Cut Spacing Scaling

None

Do not affect the spacing.

Scale by Attribute

Divides the spacing by the average value across the piece of the given attribute. A smaller value will result in larger spacing.

Cut Spacing Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Cut Offset

The size of offset randomly applied to each cut.

Cut Offset Seed

The seed of the random offset.

Curve Noise

Height

Displacement amount of the height.

Element Size

Distance between peaks of lowest frequency noise.

Splinters

Splinter Density

The amount of splinters for each cut.

Splinter Length

The length of the splinters.

Cut Fracture ID

The fracture ID for this fracture. The output attributes and groups associated with this fracture will have this tag.

Detail

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Proxy Geometry

Use Convex Decomposition

Creates proxy geometry from the high-resolution pieces using a convex decomposition.

Max Concavity

The maximum distance from a point on the geometry to it’s closest convex hull edge. Reducing this value will produce convex hulls that are a closer fit to the input geometry, but the geometry may be split into more segments.

Crease Weights

Creases control the strength of pull of the polygon faces on the subdivision surfaces, much like a magnet drawing the surface towards the reference polygon. When this is turned on, a creaseweights attribute will be created and the specified value will be applied to the vertices at the interface between the outside and inside faces. See the Subdivide SOP for more details.

Weight

Specify the creaseweights value.

Cluster

Enable Cluster

Clusters fractured pieces together into larger chunks. This can produce more realistic pieces of broken wood.

Cluster Type

Specifies how to apply the clustering to the input geometry.

Combine Pieces

Adjusts the name primitive attribute to combine pieces into clusters. This will result in fewer objects in the simulation. The constraint geometry is also updated to reflect the new pieces.

Group Constraints

The input geometry is not modified, but primitive groups are added to the constraint geometry to identify constraints between clusters, internal constraints in a cluster, etc. This can be used with the RBD Constraint Properties SOP to, for example, create stronger constraints between pieces in the same cluster. With this approach, the clustered chunks may be broken apart during the simulation by breaking the constraints within a cluster.

Offset

The offset of the cellular noise added to the input points.

Jitter

The jitter of the cellular noise added to the input points.

Size

The size of the cells for the noise added to the input points. This roughly corresponds to the size of the clusters.

Random Detachment

Randomly detach pieces from clusters.

Detach Ratio

The probability that a particular piece will be detached.

Detach Seed

The random seed used for detachment.

Constraints

Search Radius

When re-wiring incoming constraints, specify the search radius within which to look for matching connections.

Use Tags

Creates a constraint_tag string attribute on the constraint primitives instead of using groups. This allows for more flexibility and matches the Vellum constraints.

Apply Constraint Properties

Applies constraint properties to the output constraint geometry. The RBD Constraint Properties SOP can be used for advanced constraint setups.

Glue Constraint Name

Specifies the Data Name of the constraint data (for example, the Glue Constraint Relationship) to use in the DOP network.

Enable Color

Adds a color to the various constraints being created for quick identification.

Grain Color

Specifies the color for the grain constraints.

Cut Color

Specifies the color for the cut constraints.

Grain Strength

The strength of glue bonds between grains.

Cut Strength

The strength of glue bonds between cuts and splinters.

Strength Variance

Randomly varies the strength of each glue bond.

Switch to Soft Constraint when Broken

Specifies a different constraint type to switch to if the glue constraint is broken by the Bullet Solver.

Note

This parameter does not set attributes directly but determines which parameters are relevant to streamline the UI.

Soft Constraint Name

Specifies the Data Name of the constraint data (for example, the Bullet Soft Constraint Relationship) to use in the DOP network once the initial constraints are broken.

Degrees of Freedom

Specifies whether the constraint affects position, orientation, or both. This does not apply to glue constraints, which work by simulating glued chunks together as a single object with a compound collision shape.

Stiffness

Specifies the strength of the force that attempts to match the transforms of the two anchors.

This value is equivalent to the frequency of a spring.

Damping Ratio

Specifies how much damping is applied to the motion. A value of 0 specifies no damping, and a value of 1 provides just enough damping to prevent oscillation. Values between 0 and 1 allow oscillation (with some damping), and values greater than 1 provide increasingly damped motion that has no oscillation.

This value is equivalent to the damping ratio of a spring.

Custom

Guide Geometry

None

No guide geometry.

Fractured Geometry

The group that is currently being fractured will be highlighted.

Volume

Displays the volume distribution used for scattering.

Cutter Geometry

Displays the cutting geometry.

Edge Detail

Displays the cutting geometry used to generate the edge detail.

Constraint Network

Displays the constraint network.

Primary Fracture

Treat As

Whether to treat this geometry like the boundary of a solid object, or as a flat surface with no interior or exterior.

Treat Cutting Geometry As

Similar to Treat As. This is only applicable to the cutting geometry when scattering spheres or using custom cutting geometry.

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Cutting Geometry

Scatter Cutting Geo

Use scattered cutting geometry for fracturing.

Scatter From

Volume

Scatters points based on the fog volume generated.

Attribute

Scatters points based on the specified point attribute in the incoming geometry. For example, the RBD Paint SOP can be used to paint a density attribute on the geometry.

Cutter Geo

Select the type of scattered cutting geometry.

Grid

Uses a grid to perform cuts.

Sphere

Uses a polygon sphere to perform cuts.

Input Geo

Uses cutter geometry from the fourth input.

Note

If a name prim attribute exists on the geometry, only prims with a matching name will be used for the piece being fractured. Wildcards are supported.

Attribute Name

The name of the point attribute to use as a density attribute when scattering points.

Scatter Points

The number of points to scatter.

Scatter Points Scaling

None

Do not affect the number of scattered points.

Scale by Piece Volume

Multiplies the number of scattered points by the piece’s volume.

Note

This is only available with the Concrete material.

Large pieces can generate a lot more points. Use the Remap Range option for better control over the total number of points being generated.

Scale by Max Axis Length

Multiplies the number of scattered points by the piece’s bounding box’s maximum axis length.

Note

This is only available with the Concrete material.

Large pieces can generate a lot more points. Use the Remap Range option for better control over the total number of points being generated.

Scale by Attribute

Multiplies the number of scattered points by the average value across the piece of the given attribute.

Scatter Points Attribute

The name of the primitive or point float attribute to use as multiplier. The average value across the piece being fractured will be used.

Scatter Seed

The random seed for scattering points.

Scatter Normal

The normal for the volume scattered points to orient the cutting geo.

Randomize Normal

Randomizes the normal used to orient the cutting geo.

Use Input Geo

Use additional cutter geometry from the fourth input.

Note

If a name prim attribute exists on the geometry, only prims with a matching name will be used for the piece being fractured. Wildcards are supported.

Input Cutting Geo

Specifies a group from the fourth input geometry to use for fracturing.

Trim Cutting Geometry

Trims the cutting geometry for better performance.

Detriangulate Cutting Geometry

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Fog Volume

Noise Type

The type of noise. Select from None, Perlin Noise, Original Perlin Noise, Sparse Convolution Noise, Alligator Noise, Simplex Noise and Zero Centered Perlin

Volume Resolution

The resolution of the fog volume. The higher the resolution, the slower the fracturing time will be. Smaller geometry will require higher volume resolution.

Noise Frequency

The frequency of the noise. Higher values give smaller scaled details in the noise.

Noise Offset

The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.

Cutoff Density

The low density level to cutoff at. Density below this value will be discarded.

Fracture ID

The fracture ID for this fracture. The output attributes and groups associated with this fracture will have this tag.

Output Groups

Pieces Inside Cutting Geometry

Creates a primitive group containing the pieces that are enclosed by the cutting geometry. This is supported when the input geometry and cutting geometry are both treated as a solid.

Surface Inside Cutting Geometry

Creates a group containing the polygons from the original input geometry that are enclosed by the cutting geometry. This is supported when the cutting geometry is treated as a solid.

Interior Seams

Creates a group containing edges representing the seams where the cutting geometry intersects itself.

Exterior Seams

Creates a group containing edges representing the seams where the cutting geometry intersects the original input geometry.

Chipping

Enable Chipping

Break off corners of pieces to create chips.

Chipping Ratio

The overall ratio out of all the pieces to perform chipping on.

Seed

The overall seed for the ratio of chipping.

Randomness

Randomizes the chipping ratio for each piece by this amount, when fracturing per piece.

Corner Ratio

The ratio of corner points to use to generate chipping cutting planes.

Corner Depth

A normalized distance from corner to the center of the piece where the chipping plane will be instantiated.

Directional Noise

Amount of noise to add to the corner normal to align the cutting plane to.

Detriangulate

Converts geometry back to the original N-gons after applying a boolean operation (which internally converts the geometry to triangles). Disabling this may be necessary to avoid producing self-intersections when multiple levels of fracturing are performed. See the Boolean SOP tips for more information.

Detail

Detail Size

The size of the polygons added for the edge and interior detail.

Edge Detail

Use Boolean to obtain edge detail.

Noise Height

Scales the amount of displacement.

Noise Element Size

The size of the noise pattern. Higher values give larger scaled details in the noise.

Interior Detail

Adds noise to the interior points, scaled based on their distance to the surface.

Noise Amplitude

Scales the amount of displacement.

Noise Type

The type of noise added to the interior points.

Frequency

The frequency of the noise. Higher values give smaller scaled details in the noise.

Offset

The offset of the input into the noise function. If you visualize the noise as a 2D graph or 3D height field, this has the effect of “panning” across the space of possible noise outputs. If you have the general noise effect you want but just want to get a different set of values for a different look, try changing the offset.

Crease Weights

Creases control the strength of pull of the polygon faces on the subdivision surfaces, much like a magnet drawing the surface towards the reference polygon. When this is turned on, a creaseweights attribute will be created and the specified value will be applied to the vertices at the interface between the outside and inside faces. See the Subdivide SOP for more details.

Weight

Specify the creaseweights value.

Proxy Geometry

Default

Uses the default voronoi fractured geometry.

Convex Decomposition

Performs a convex decomposition from the fractured input geometry.

Packed Spheres

Uses packed sphere primitives from the fractured input geometry.

Max Concavity

The maximum distance from a point on the geometry to it’s closest convex hull edge. Reducing this value will produce convex hulls that are a closer fit to the input geometry, but the geometry may be split into more segments.

Voxel Size

The size of voxels in the output VDB volume. Surface features smaller than this will not be in the output VDB.

Min Radius in Voxels

Determines the smallest sphere size in voxel units.

Max Radius in Voxels

Determines the largest sphere size in voxel units.

Max Spheres

No more than this number of spheres are generated per VDB primitive.

Constraints

Search Radius

When re-wiring incoming constraints, specify the search radius within which to look for matching connections.

Use Tags

Creates a constraint_tag string attribute on the constraint primitives instead of using groups. This allows for more flexibility and matches the Vellum constraints.

Apply Constraint Properties

Applies constraint properties to the output constraint geometry. The RBD Constraint Properties SOP can be used for advanced constraint setups.

Glue Constraint Name

Specifies the Data Name of the constraint data (for example, the Glue Constraint Relationship) to use in the DOP network.

Enable Color

Adds a color to the various constraints being created for quick identification.

Primary Strength

The strength of the glue bonds of primary fracture.

Chipping Strength

The strength of glue bonds for corner chips.

Strength Variance

Randomly varies the strength of each glue bond.

Switch to Soft Constraint when Broken

Specifies a different constraint type to switch to if the glue constraint is broken by the Bullet Solver.

Note

This parameter does not set attributes directly but determines which parameters are relevant to streamline the UI.

Soft Constraint Name

Specifies the Data Name of the constraint data (for example, the Bullet Soft Constraint Relationship) to use in the DOP network once the initial constraints are broken.

Degrees of Freedom

Specifies whether the constraint affects position, orientation, or both. This does not apply to glue constraints, which work by simulating glued chunks together as a single object with a compound collision shape.

Stiffness

Specifies the strength of the force that attempts to match the transforms of the two anchors.

This value is equivalent to the frequency of a spring.

Damping Ratio

Specifies how much damping is applied to the motion. A value of 0 specifies no damping, and a value of 1 provides just enough damping to prevent oscillation. Values between 0 and 1 allow oscillation (with some damping), and values greater than 1 provide increasingly damped motion that has no oscillation.

This value is equivalent to the damping ratio of a spring.

See also

Geometry nodes