[Home](./index.md) > [server](./server.md) > [CollisionGroupsBuilder](./server.collisiongroupsbuilder.md) ## CollisionGroupsBuilder class A helper class for building and decoding collision groups. When to use: creating custom collision filters for colliders and rigid bodies. Do NOT use for: per-frame changes; collision group changes are usually infrequent. **Signature:** ```typescript export default class CollisionGroupsBuilder ``` ## Remarks Use the static methods directly to encode or decode collision group masks. \*\*Category:\*\* Physics ## Methods

Method	Modifiers	Description
[buildRawCollisionGroups(collisionGroups)](./server.collisiongroupsbuilder.buildrawcollisiongroups.md)	`static`	Builds a raw collision group mask from a set of collision groups.
[decodeCollisionGroups(collisionGroups)](./server.collisiongroupsbuilder.decodecollisiongroups.md)	`static`	Decodes collision groups into their string equivalents.
[decodeRawCollisionGroups(groups)](./server.collisiongroupsbuilder.decoderawcollisiongroups.md)	`static`	Decodes a raw collision group mask into a set of collision groups.
[isDefaultCollisionGroups(collisionGroups)](./server.collisiongroupsbuilder.isdefaultcollisiongroups.md)	`static`	Checks if the collision groups are the default collision groups.