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VolumeMeasurement

Source

Copying and pasting? We've got you covered! You can find the full source code of this tutorial here.

📐 Measuring volumes​

Space control is one of the most important elements of BIM applications. In this tutorial, you'll learn how to expose an volume measurement tool to your end users. We will import:

  • @thatopen/components to set up the barebone of our app.
  • @thatopen/components-front to use some frontend-oriented components.
  • Stats.js (optional) to measure the performance of our app.
import Stats from "stats.js";
import * as OBC from "@thatopen/components";
import * as OBCF from "@thatopen/components-front";

🌎 Setting up a simple scene​

We will start by creating a simple scene with a camera and a renderer. If you don't know how to set up a scene, you can check the Worlds tutorial.

const container = document.getElementById("container")!;

const components = new OBC.Components();

const worlds = components.get(OBC.Worlds);

const world = worlds.create<
  OBC.SimpleScene,
  OBC.SimpleCamera,
  OBCF.PostproductionRenderer
>();

world.scene = new OBC.SimpleScene(components);
world.renderer = new OBCF.PostproductionRenderer(components, container);
world.camera = new OBC.SimpleCamera(components);

components.init();

world.camera.controls.setLookAt(5, 5, 5, 0, 0, 0);

world.scene.setup();

const grids = components.get(OBC.Grids);
grids.create(world);

We'll make the background of the scene transparent so that it looks good in our docs page, but you don't have to do that in your app!

world.scene.three.background = null;

🧳 Loading a BIM model​

We'll start by adding a BIM model to our scene. That model is already converted to fragments, so it will load much faster than if we loaded the IFC file.

Fragments?

If you are not familiar with fragments, check out the IfcLoader tutorial!

const fragments = new OBC.FragmentsManager(components);
const file = await fetch(
  "https://thatopen.github.io/engine_components/resources/small.frag",
);
const data = await file.arrayBuffer();
const buffer = new Uint8Array(data);
const model = fragments.load(buffer);
world.scene.three.add(model);

🛠️ Getting the volume measurements​

First, let's get an instance of the volume measurement component and initialize it.

const dimensions = components.get(OBCF.VolumeMeasurement);
dimensions.world = world;
dimensions.enabled = true;

🔦 Getting the highlighter​

Now, let's get an instance of the highlighter component and initialize it to be able to highlight the computed volume.

Highlighter?

If you are not familiar with the highlighter component, check out the highlighter tutorial!

const highlighter = components.get(OBCF.Highlighter);
highlighter.setup({ world });

Now we'll simply take the computed volume and log it in the console. Also, when the highlighter is cleared, we'll also clear the volume dimension.

highlighter.events.select.onHighlight.add((event) => {
  const volume = dimensions.getVolumeFromFragments(event);
  console.log(volume);
});

highlighter.events.select.onClear.add(() => {
  dimensions.clear();
});

⏱️ Measuring the performance (optional)​

We'll use the Stats.js to measure the performance of our app. We will add it to the top left corner of the viewport. This way, we'll make sure that the memory consumption and the FPS of our app are under control.

const stats = new Stats();
stats.showPanel(2);
document.body.append(stats.dom);
stats.dom.style.left = "0px";
stats.dom.style.zIndex = "unset";
world.renderer.onBeforeUpdate.add(() => stats.begin());
world.renderer.onAfterUpdate.add(() => stats.end());

🎉 Wrap up​

That's it! You have created an app that can create and delete volume dimensions on any 3D object. Congratulations!