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Clipping planes can be used in Three.js to clip the Troika Three-Text by setting up a custom shader material for the text mesh. This can be achieved by following these steps:

1. Create a new material with a custom shader that includes the use of clipping planes. This can be done using the ShaderMaterial class in Three.js.

2. In the vertex shader, define the clipping planes as uniforms and pass them to the fragment shader.

3. In the fragment shader, discard fragments that are outside the clipping planes by using the clipPlaneDistance and clipPlaneNormal functions.

4. Apply the custom material to the Troika Three-Text mesh.

Here's some sample code that demonstrates how to use clipping planes to clip Troika Three-Text:

// Create clipping planes
const clippingPlanes = [
  new THREE.Plane(new THREE.Vector3(1, 0, 0), 0.5),
  new THREE.Plane(new THREE.Vector3(-1, 0, 0), 0.5),
];

// Create custom material with clipping planes
const material = new THREE.ShaderMaterial({
  uniforms: {
    clippingPlanes: {
      type: 'fv4',
      value: clippingPlanes.map(plane => new THREE.Vector4().fromArray(plane.normal.toArray().concat(plane.constant))),
    },
    numClippingPlanes: {
      type: 'i',
      value: clippingPlanes.length,
    },
  },
  vertexShader: `
    uniform vec4 clippingPlanes[MAX_CLIPPING_PLANES];
    uniform int numClippingPlanes;

    varying vec3 vWorldPosition;

    void main() {
      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
      vWorldPosition = (modelMatrix * vec4(position, 1.0)).xyz;

      for (int i = 0; i < numClippingPlanes; i++) {
        if (dot(vWorldPosition, clippingPlanes[i].xyz) + clippingPlanes[i].w > 0.0) {
          gl_ClipDistance[i] = 0.0;
        } else {
          gl_ClipDistance[i] = 1.0;
        }
      }
    }
  `,
  fragmentShader: `
    uniform vec4 clippingPlanes[MAX_CLIPPING_PLANES];
    uniform int numClippingPlanes;

    varying vec3 vWorldPosition;

    void main() {
      bool anyInside = false;
      for (int i = 0; i < numClippingPlanes; i++) {
        if (dot(vWorldPosition, clippingPlanes[i].xyz) + clippingPlanes[i].w > 0.0) {
          discard;
        } else {
          anyInside = true;
        }
      }

      if (!anyInside) {
        discard;
      }

      gl_FragColor = vec4(1.0);
    }
  `,
});

// Apply custom material to Troika Three-Text mesh
const textGeometry = new TroikaTextGeometry('Hello, world!', {
  font: new THREE.Font(/* ... */),
});
const textMesh = new THREE.Mesh(textGeometry, material);
scene.add(textMesh);

Note that the above code assumes that the MAXCLIPPINGPLANES constant is defined somewhere in your code with a value greater than or equal to the number of clipping planes you're using. You can adjust the values of the clipping planes and the custom material uniforms to get the desired clipping effect for your Troika Three-Text mesh.