The tyPush modifier is an alternative to 3ds Max’s built-in Push modifier, that allows you to specify a push direction, rather than simply pushing vertices along their normals.
Push vertices: when selected, mesh vertices will be pushed along the specified direction.
Push elements: when selected, mesh elements will be pushed out from the center of the mesh.
Use vertex selection: when enabled, only selected vertices will be affected.
Vertex normals: vertices will be pushed along the direction of their normals.
Local space vector: vertices will be pushed along the specified vector in local space.
World space vector: vertices will be pushed along the specified vector in world space.
Open edges outwards: vertices on open edges will be pushed outwards, perpendicular to the normals of their adjacent faces.
Amount: the amount to push vertices along the specified direction.
X/Y/Z: the user-defined push vector.
Outwards from center: elements will be pushed away from the center of the mesh, relative to their distance to the center.
Outwards from gizmo: elements will be pushed away from the center of the sub-object gizmo, relative to their distance to the center.
Outward above gizmo: elements will be pushed along the z-axis of the sub-object gizmo, if their center is above the gizmo, relative to their distance from the gizmo along the z-axis.
Using element bbox: the center of each element will be the center of each element’s bounding box.
Using element verts: the center of each element will be the average position of its vertices.
Amount %: controls how far each mesh element should be pushed out (this value is a multiplier on the relative distance - calculated by the given element push mode specified above).
Distance: elements within this distance from the specified center will be fully affected.
Falloff: the effect on elements beyond the base distance, but within this falloff distance, will diminish according to the inverse-square law.
Allow non-manifold edges: when enabled, non-manifold edges (edges with 3+ adjacent faces) will be used in the element flood-fill algorithm.
The edges in a manifold (non-degenerate) mesh will only ever have up to 2 adjacent faces (open edges have 1 adjacent face, closed edges have 2 adjacent faces). In a non-manifold (degenerate) mesh, some edges may have 3 or more adjacent faces. If the element flood-fill algorithm (the algorithm that is used to find connected mesh elements by following edge-face adjacencies) is not set to recognize non-manifold edges, this can lead to situations where faces connected by non-manifold edges may be treated as separate elements, even if they appear to be connected. Alternatively, if non-manifold edges are recognized by the algorithm, this can lead to situations where seemingly-separate elements connected only by a single edge will be considered part of the same element.