Per vertex properties for cloth - Lumberyard User Guide

Per vertex properties for cloth

This feature is in preview release and is subject to change.

Cloth properties can be set per cloth particle using the vertex color tools in your content creation application. In the Cloth modifier, in FBX Settings, you can choose which vertex color stream and which color channel in the stream represents each property. You can use a different stream for each property, or combine multiple properties into a single vertex color stream by storing the properties in different color channels.

Inverse Mass

Inverse Mass calculates a per cloth particle mass value. If no vertex color stream is provided, then the Inverse Mass value of all vertices will be 1.0 by default. The value range for Inverse Mass is 0.0 to 1.0.

An Inverse Mass value of 0.0 excludes the vertex from the cloth simulation. Vertices with a 0.0 Inverse Mass value will be static.

Per cloth particle mass is calculated as VertexMass = 1.0/InverseMass. For example, if the Inverse Mass value in the color channel is 0.3, then the resulting cloth particle mass value is 3.33. The smaller the Inverse Mass value, the greater the cloth particle mass.

Motion Constraints

Motion constraints limit the movement of a simulated cloth particle to an area defined by a sphere. The sphere's position is relative to the corresponding unsimulated vertex position. For a detailed explanation of Motion Constraints, see Cloth simulation constraints.

The Motion Constraints per vertex property calculates the radius of the sphere. Motion Constraints have a value range of 0.0 to 1.0.

A Motion Constraints value of 0.0 constrains the cloth particle to the corresponding unsimulated vertex.

Backstop

Backstop prevents a simulated cloth particle from entering an area defined by a sphere. The sphere's position is relative to the corresponding unsimulated vertex position. There are two Backstop properties that you can define per vertex, Backstop Offset and Backstop Radius. For a detailed explanation of Backstop, see Cloth simulation constraints.

Backstop Offset

Backstop Offset defines the backstop sphere's offset along the normal of the corresponding unsimulated vertex. The Backstop Offset value range, 0.0 to 1.0, is remapped to a range between -1.0 and 1.0.

A Backstop Offset value of 0.0 is remapped to -1.0 and places the backstop sphere in front of the unsimulated vertex.

A Backstop Offset value of 1.0 places the backstop sphere behind the unsimulated vertex.

A Backstop Offset value of 0.5 is remapped to 0.0 and places the backstop sphere on the unsimulated vertex.

Backstop Radius

Backstop Radius calculates the radius of the backstop sphere. Backstop Radius has a value range of 0.0 to 1.0.

A Backstop Radius value of 0.0 disables the backstop for the corresponding vertex.