Decimals and Measurement System

I know that using decimals with JS is discouraged because of accuracy problems when doing calculations.

Is this valid for Babylon.js also?

I want to create a Metric and Imperial measurement system (Centimeters and inches) and I am considering whether to allow decimals.

In general any tips about this?

I was considering to do something like:

1 unit = 1 CM
1 unit = 1 INCH + decimals

OR INSTEAD use integers to simulate decimals? e.g.

100 units = 1 CM
100 units = 1 INCH

Use toFixed() JS method to restrict the decimal numbers to 2? Because now I get very big numbers with 10+ decimals.

BJS is just JS. So the same computation accuracy.

@jerome so I want to use round/whole numbers then. But not sure how to simulate this when dragging.

Imagine that I have a tube and I can drag the end points to make the tube bigger in length.

While doing so, the length of the tube is currently calculated with decimals. Like this Recording #511

Is there a way to make it go 1-by-1 whole units? Meaning that only round units are used?

For the dragging I use:

scene.onPointerObservable.add((pointerInfo) => {
switch (pointerInfo.type) {
                case BABYLON.PointerEventTypes.POINTERDOWN:
                    if(pointerInfo.pickInfo.hit && pointerInfo.pickInfo.pickedMesh != ground) {
                case BABYLON.PointerEventTypes.POINTERUP:
                case BABYLON.PointerEventTypes.POINTERMOVE:          

For the mouse position:

pickResult = scene.pick(scene.pointerX, scene.pointerY);

I hope this makes sense.


I used Math.floor() on the X and Z coordinates and the numbers are whole when I draw the lines vertically or horizontally. If I draw the lines diagonally the numbers are not whole.

const x = pickResult.pickedPoint.x,
         z = pickResult.pickedPoint.z,
         pickedPoint = new BABYLON.Vector3(

Any ideas why this happens? See Recording #512

I tried Math.round() also but there is no difference.

Like this maybe
return new BABYLON.Vector3(parseFloat(pickinfo.pickedPoint.x.toFixed(2)), 0, parseFloat(pickinfo.pickedPoint.z.toFixed(2)))

No that makes no difference actually.

I ended up rounding down the output of the distance between the 2 vectors.

Its not the most accurate solution but for now it will work. Because the distance between the two vectors is still a float on the actual world coordinates.

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