Please add a separate Line2 threshold for world / pixel based lines.

[nzjony]

Description

We use Line2 for both screen space and world space lines.

Unfortunately, we need to have different thresholds for pixel / world units. Because for example, a threshold of 10 looks quite small, but 10 world units is quite big (of course depending on the camera distance).

Solution

Something like:

		const threshold = ( raycaster.params.Line2 !== undefined ) ?
			( worldUnits ? ( raycaster.params.Line2.thresholdWorld || 0 ) :
				( raycaster.params.Line2.thresholdPixel || 0 ) ) : 0;

In the raycast function of LineSegments2.js

I'm happy to make a PR, just want to get a thumbs up before I do it.

Alternatives

For now, I'll make a change to three.js locally and use patch-package to apply it.

Additional context

No response

[WestLangley]

@gkjohnson I am curious as to how you feel about this. 😇

[gkjohnson]

These thresholds are used for making it easier to select items with a mouse so to me it's much more sensible to specify them in pixel units rather than providing a separate option for a world threshold. Ie we can change the Line2 world raycasting logic to allow for intersecting the line if the mouse is within the "threshold" amount of pixels around the projected shape. So:

• Find the closest point to the ray on the line
• Calculate the "world width" of a pixel at the distance of the point to the camera
• Use that world width and threshold factor to determine whether the point is close enough

Alternatively the threshold could be used to specify the minimum screen width to use for the calculation instead of unnecessarily expanding an already large world-units line that is close to the camera.

[nzjony]

@WestLangley @gkjohnson , thanks for the comments.

@gkjohnson that sounds like a very clever approach. 👍