# Clipping Nrrd models

**URL:** <https://discourse.threejs.org/t/clipping-nrrd-models/40463>\
**Category:** Questions\
**Tags:** clipping-planes\
**Created:** [July 18, 2022, 4:35pm UTC](https://discourse.threejs.org/t/clipping-nrrd-models/40463 "2022-07-18T16:35:47Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Jeff\_Boker](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/jeff_boker/32/22518_2.png) [@Jeff\_Boker](https://discourse.threejs.org/u/Jeff_Boker)\
**Post date:** [July 18, 2022, 4:35pm UTC](https://discourse.threejs.org/t/clipping-nrrd-models/40463/1 "2022-07-18T16:35:47Z")

</div>

I am taking the example code for rendering volumes using NRRD loader from [here](https://threejs.org/examples/webgl2_materials_texture3d.html). I wanted to be able to add clipping planes so I took the following example [here](https://threejs.org/examples/?q=clip#webgl_clipping) to combine the two together. However, it seems that clipping does not work the same way with ShaderMaterial as it did for me with other material types. I was wondering how I could clip my nrrd model in three js:

```javascript
		function init() {

			scene = new THREE.Scene();

			// Create renderer
			renderer = new THREE.WebGLRenderer();
			renderer.setPixelRatio( window.devicePixelRatio );
			renderer.setSize( window.innerWidth, window.innerHeight );
			document.body.appendChild( renderer.domElement );

			// Create camera (The volume renderer does not work very well with perspective yet)
			const h = 512; // frustum height
			const aspect = window.innerWidth / window.innerHeight;
			camera = new THREE.OrthographicCamera( - h * aspect / 2, h * aspect / 2, h / 2, - h / 2, 1, 1000 );
			camera.position.set( - 64, - 64, 128 );
			camera.up.set( 0, 0, 1 ); // In our data, z is up

			// Create controls
			controls = new OrbitControls( camera, renderer.domElement );
			controls.update();
			controls.addEventListener( 'change', render );
			controls.target.set( 64, 64, 128 );
			controls.minZoom = 0.5;
			controls.maxZoom = 40;

			// Display world axis
			var axesHelper = new THREE.AxesHelper( 1000 );
			scene.add( axesHelper );

			// Lighting is baked into the shader a.t.m.
			// let dirLight = new DirectionalLight( 0xffffff );
			// Light source positioned above the scene
			const hemiLight = new THREE.HemisphereLight( 0xffffff, 0x444444 );
			hemiLight.position.set( 0, 100, -100 );
			scene.add( hemiLight );

			// Light source positioned at front of tote
			const dirLight = new THREE.DirectionalLight( 0xffffff );
			dirLight.position.set( 0, 40, 50 );
			scene.add( dirLight );

			// *****Clipping planes:*****

			const localPlane = new THREE.Plane( new THREE.Vector3( 0, - 1, 0 ), 0.8 );
			const globalPlane = new THREE.Plane( new THREE.Vector3( - 1, 0, 0 ), 0.1 );

			var planeHelper = new THREE.PlaneHelper(localPlane, 500);
			scene.add(planeHelper);

			// The gui for interaction
			volconfig = { clim1: 0.25, clim2: 0.5, renderstyle: 'mip', isothreshold: 0.15, colormap: 'viridis' };
			const gui = new GUI();
			gui.add( volconfig, 'clim1', 0, 0.5, 0.01 ).onChange( updateUniforms );
			gui.add( volconfig, 'clim2', 0, 0.5, 0.01 ).onChange( updateUniforms );
			gui.add( volconfig, 'colormap', { gray: 'gray', viridis: 'viridis' } ).onChange( updateUniforms );
			gui.add( volconfig, 'renderstyle', { mip: 'mip', iso: 'iso' } ).onChange( updateUniforms );
			gui.add( volconfig, 'isothreshold', 0, 100, 0.01 ).onChange( updateUniforms );

			// Load the data ...
			new NRRDLoader().load( './test.nrrd', function ( volume ) {

				// Texture to hold the volume. We have scalars, so we put our data in the red channel.
				// THREEJS will select R32F (33326) based on the THREE.RedFormat and THREE.FloatType.
				// Also see https://www.khronos.org/registry/webgl/specs/latest/2.0/#TEXTURE_TYPES_FORMATS_FROM_DOM_ELEMENTS_TABLE
				// TODO: look the dtype up in the volume metadata
				const texture = new THREE.Data3DTexture( volume.data, volume.xLength, volume.yLength, volume.zLength );
				texture.format = THREE.RedFormat;
				texture.type = THREE.FloatType;
				texture.minFilter = texture.magFilter = THREE.LinearFilter;
				texture.unpackAlignment = 1;
				texture.needsUpdate = true;

				// Colormap textures
				cmtextures = {
					viridis: new THREE.TextureLoader().load( 'textures/cm_viridis.png', render ),
					gray: new THREE.TextureLoader().load( 'textures/cm_gray.png', render )
				};

				// Material
				const shader = VolumeRenderShader1;

				const uniforms = THREE.UniformsUtils.clone( shader.uniforms );

				uniforms['u_data'].value = texture;
				uniforms['u_size'].value.set( volume.xLength, volume.yLength, volume.zLength );
				uniforms['u_clim'].value.set( volconfig.clim1, volconfig.clim2 );
				uniforms['u_renderstyle'].value = volconfig.renderstyle == 'mip' ? 0 : 1; // 0: MIP, 1: ISO
				uniforms['u_renderthreshold'].value = volconfig.isothreshold; // For ISO renderstyle
				uniforms['u_cmdata'].value = cmtextures[volconfig.colormap];

				material = new THREE.ShaderMaterial( {
					uniforms: uniforms,
					vertexShader: shader.vertexShader,
					fragmentShader: shader.fragmentShader,
					//side: THREE.BackSide, // The volume shader uses the backface as its "reference point"

					side: THREE.DoubleSide,
					// *****Clipping setup (material):*****
					clippingPlanes: [localPlane],
					blending: THREE.AdditiveBlending,
					depthWrite: false,
					clipShadows: true
				} );

				// THREE.Mesh
				const geometry = new THREE.BoxGeometry( volume.xLength, volume.yLength, volume.zLength );
				geometry.translate( volume.xLength / 2 - 0.5, volume.yLength / 2 - 0.5, volume.zLength / 2 - 0.5 );

				const mesh = new THREE.Mesh( geometry, material );
				scene.add( mesh );

				// *****Clipping setup (renderer):*****
				const globalPlanes = [globalPlane],
					Empty = Object.freeze( [] );
				renderer.clippingPlanes = Empty; // GUI sets it to globalPlanes
				renderer.localClippingEnabled = true;
				
				const gui = new GUI(),
					folderLocal = gui.addFolder( 'Local Clipping' ),
					propsLocal = {
						get 'Enabled'() {
							return renderer.localClippingEnabled;
						},
						set 'Enabled'( v ) {
							renderer.localClippingEnabled = v;
						},
						get 'Plane'() {
							return localPlane.constant;
						},
						set 'Plane'( v ) {
							localPlane.constant = v;
						}
					},

					folderGlobal = gui.addFolder( 'Global Clipping' ),
					propsGlobal = {
						get 'Enabled'() {
							return renderer.clippingPlanes !== Empty;
						},
						set 'Enabled'( v ) {
							renderer.clippingPlanes = v ? globalPlanes : Empty;
						},
						get 'Plane'() {
							return globalPlane.constant;
						},
						set 'Plane'( v ) {
							globalPlane.constant = v;
						}
					};
				folderLocal.add( propsLocal, 'Enabled' );
				folderLocal.add( propsLocal, 'Plane', 0.3, 80 );
				render();
			} );
		}

		function updateUniforms() {
			material.uniforms['u_clim'].value.set( volconfig.clim1, volconfig.clim2 );
			material.uniforms['u_renderstyle'].value = volconfig.renderstyle == 'mip' ? 0 : 1; // 0: MIP, 1: ISO
			material.uniforms['u_renderthreshold'].value = volconfig.isothreshold; // For ISO renderstyle
			material.uniforms['u_cmdata'].value = cmtextures[volconfig.colormap];
			render();

		}
			render();

		}

		function render() {

			renderer.render( scene, camera );

		}

```

---

<div class="post-metadata">

**Author:** ![agucci](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@agucci](https://discourse.threejs.org/u/agucci)\
**Post date:** [October 12, 2023, 4:51pm UTC](https://discourse.threejs.org/t/clipping-nrrd-models/40463/2 "2023-10-12T16:51:22Z")

</div>

Hi, I am currently trying to do the exact same thing by clipping my NRRD volume. Just wanted to bump this topic to the top to know if anyone had a solution ?