Raycasting wider than a single ray to intersect objects

In trying to detect touch events on objects, raycasting works well for a single point. But with touch devices, the touch area is that, an area, (circle) rather than a point.

How would you find the intersection of objects with an on-screen area? Raycasting each point of the area seems overkill.

You can use Sphere or Box3 placed at the centre touch point - and determine collisions with things around it (mesh-bvh may also be quite useful, especially if you have a complex scene.)