How to implement clipping planes on custom shader materials

I’m trying to implement clipping planes on a shader for a ThreeJS extension called volumetricSpotlightMaterial which can be viewed here: threex.volumetricspotlight/threex.volumetricspotlightmaterial.js at master · jeromeetienne/threex.volumetricspotlight · GitHub. The ThreeJS doc’s specifies to enable the clipping boolean property on the shader material which I have done and I have passed the clipping plane to the renderer’s clippingPlanes array property but the spotlight is still passing through the plane.

I have made a spot lite myself using a ThreeJS built in material. Ans simply just passing the plane to the render works perfectly.

I’m at a bit of a loss as I’m sure I have taken all the steps. Any takers ? :slight_smile:

It would be easier to help if you provided a simple live example.