diff --git a/packages/modeling/src/maths/mat4/index.d.ts b/packages/modeling/src/maths/mat4/index.d.ts
index 3ef69674e..94cbeae57 100644
--- a/packages/modeling/src/maths/mat4/index.d.ts
+++ b/packages/modeling/src/maths/mat4/index.d.ts
@@ -12,6 +12,7 @@ export { default as fromXRotation } from './fromXRotation'
 export { default as fromYRotation } from './fromYRotation'
 export { default as fromZRotation } from './fromZRotation'
 export { default as identity } from './identity'
+export { default as isIdentity } from './isIdentity'
 export { default as isMirroring } from './isMirroring'
 export { default as mirrorByPlane } from './mirrorByPlane'
 export { default as multiply } from './multiply'
diff --git a/packages/modeling/src/maths/mat4/isIdentity.d.ts b/packages/modeling/src/maths/mat4/isIdentity.d.ts
new file mode 100644
index 000000000..cc0e5c7ac
--- /dev/null
+++ b/packages/modeling/src/maths/mat4/isIdentity.d.ts
@@ -0,0 +1,5 @@
+import Mat4 from './type'
+
+export default isIdentity
+
+declare function isIdentity(matrix: Mat4): boolean