The Fracture meshes rollout has parameters which provide control over how fracture meshes (meshes generated by the various fracture modes to slice an input mesh) are created.
Square/circle: for fracture modes that use planar meshes to cut input meshes (ex: planar fracture mode), this controls what shape the planar mesh will take. In some situations where having visible edges on planar meshes is undesirable, the “circle” mode can be selected.
Segment size: controls the maximum length of a subdivided edge, on a fracture mesh. When disabled, fracture meshes will not be subdivided. When enabled, lower values generate more dense fracture meshes (resulting in more detailed fractures).
Max segments: controls the maximum number of subdivision segments that may be generated for a given axis or dimension of a fracture mesh. Smaller values will prevent fracture meshes from being generated with too many segments, regardless of what value is specified for the segment size parameter.
Material ID: controls what material ID value will be assigned to all fracture meshes.
UVW scale: this value is a scale multiplier applied to all UVW coordinates assigned to fracture meshes.
Smoothing mode: controls whether fracture meshes will be assigned smoothing groups.
Cull external faces: when enabled, faces on fracture meshes that do not intersect the hull of the input mesh will be culled, prior to fracture. Typically these faces are not required (as they do not affect the fracture result), so leaving this setting enabled will increase the overall speed of the fracture operation.
Cull with convex hull: when enabled, the convex hull of the input mesh will be used to cull external fracture meshes faces. When disabled, the input mesh itself will be used to compute fracture mesh intersections and cull external faces.
Cull internal open elements: when enabled, open elements (fracture mesh elements with open edges) that are inside of the input mesh hull will be culled prior to fracture.
Enabling “cull internal open elements” can help prevent fracture artifacts in cases where it is known that fracture meshes have open elements inside the input mesh hull. For example, if you are performing a Voronoi fracture and have enabled cell wall culling, it is likely that orphan cell walls (cell walls that don’t connect to other cell walls at a junction) will be generated. Enabling “cull internal open elements” will remove those orphan walls, leading to results that are less likely to contain artifacts (because the PRISM volume slice function prefers fracture meshes that fully cross the surface boundaries of input meshes, rather than those that only partially intersect it).
Add shell: when enabled, fracture meshes will be extruded along their surface normals, giving them volume.
Thickness: controls how thick the shell extrusion will be.
Noise offset: controls how shell noise will be offset, on a per-fracture-mesh basis. Increasing this setting will ensure that multiple fracture meshes will have the appearance of more randomized shell noise.
Unify noise parameters: when enabled, all fracture modes will share the same noise A/B parameters. When disabled, each mode will have its own unique noise A/B parameters.
Extract meshes: clicking this will extract fracture meshes to a new editable mesh object.
Extract intersections: clicking this will extract fracture mesh intersection lines to a new editable spline object.