fixes

src/lib/components/App.svelte

@@ -6,14 +6,16 @@
 
 	let progress: Writable<number | undefined>;
 	let showSlices = 1;
+	let maxZ = 0;
 	let progressLayer: Writable<number>;
 </script>
 
 <Canvas>
-	<Scene bind:progress bind:showSlices bind:progressLayer />
+	<Scene bind:progress bind:showSlices bind:progressLayer bind:maxZ />
 </Canvas>
 
 <div class="controls">
+	<input type="number" bind:value={maxZ} />
 	<input type="range" min="0" max="1" step="0.001" bind:value={showSlices} orient="vertical" />
 </div>
 
@@ -31,6 +33,10 @@
 		height: 80%;
 	}
 
+	input[type='number'] {
+		width: 60px;
+	}
+
 	.controls {
 		display: flex;
 		flex-direction: column;

src/lib/components/Scene.svelte

@@ -58,6 +58,7 @@
 	export let progress = writable<number | undefined>(undefined);
 	export let progressLayer = writable(0);
 	export let showSlices = 1;
+	export let maxZ = 0;
 
 	export let maxNonPlanarAngle = MathUtils.degToRad(20);
 	export let bedNormal = new Vector3(0, 0, 1);
@@ -98,7 +99,7 @@
 />
 
 {#each $layers as { geometry, type }, i}
-	{@const visible = showSlices >= i / $layers.length}
+	{@const visible = maxZ !== 0 ? i === maxZ : showSlices >= i / $layers.length}
 	{@const color = new Color(Math.random() * 0xffffff)}
 	<!---{@const color = new Color(0, i / $layers.length, 0.2)}-->
 	{#if type === LayerType.Line}