The point where two surfaces meet is called an "intersection" or a "junction."
The point at which two surfaces come together is called a junction or an intersection. This can create a seam or a joint, depending on how the surfaces are connected.
The force that opposes motion between surfaces is called friction. It is caused by the interactions between atoms and molecules on the two surfaces in contact.
The sticking points between two surfaces that cause friction are called "asperities." These microscopic irregularities on the surfaces of objects interlock and resist movement, leading to frictional forces.
The force that resists sliding motion between two surfaces in contact is called friction. Friction is caused by the roughness of the surfaces and the molecular interaction between them, which opposes the relative motion between the surfaces.
The friction between moving surfaces is called kinetic friction. It occurs when two surfaces are in contact and move relative to each other, causing resistance to their motion.
The point at which two surfaces come together is called a junction or an intersection. This can create a seam or a joint, depending on how the surfaces are connected.
it if called a edge for a 3D shape
interface
The friction that two surfaces excert on each other when they rub against each other is called a friction.
The space between two lines or surfaces that meet is called the "angle" if it refers to the measure of rotation between them, or "gap" if it refers to the physical distance separating them. In geometric terms, angles are typically measured in degrees or radians. If the surfaces are not intersecting, the term "clearance" might also be used to describe the space between them.
I believe you are referring to an area of the roof called a valley. A valley is formed anywhere the downward slope of two roof surfaces meet.
... are straight lines where two planar surfaces meet.
Valley
When in reference to architecture, arris refers to the sharp edge formed when two curved or flat surfaces meet. The surfaces must meet at a salient angle.
The flat surfaces on a pyramid are called faces. A pyramid has one base and triangular faces that meet at a single point called the apex. On a cube or rectangular prism, the flat surfaces are called faces as well. But unlike a pyramid, a cube has six square faces, while a rectangular prism has two rectangular bases and four rectangular faces.
friction
The Force between two unmoving surfaces is called Static Friction. Were I got Information: Off the top of my head.