One-point perspective is a fundamental technique for creating a sense of space in drawing and design. It helps to convey depth and volume on a flat surface.

The main idea is that all lines that go into the distance converge at a single point on the horizon, called the vanishing point.
For example, a classic room view is when you look straight at one wall, and the lines of the floor, ceiling, and walls converge at a single point in front of you. This is the simplest and most common way to show perspective.

But one-point perspective can also apply to other views. For instance, a 3D sketch plan is a top-down view of a room, where you can also see lines converging to one point. Despite the changed angle, the perspective center remains singular.

Both these approaches — the classic view and the sketch plan — help understand and convey spatial relationships and depth.

The vanishing point on the horizon line can be placed exactly in the center — or shifted left or right (image below).

1. When it's centered, you see both side walls equally.
2. If it moves right, the left wall opens up, and the right wall shrinks in view.
3. If it moves left, the right wall becomes more visible, and the left wall less so.

Horizon line height matters too.

It’s usually placed at about 1.6–1.65 m (around 5′3″–5′5″) — the average eye level of an adult.
But in some cases, to reveal more of the perspective, you can place the horizon line higher (or lower) depending on the effect you want to achieve.

When using these techniques, it's important to first determine where the boundary of the room will be. In the video, I do this by eye.

When drawing one-point perspective by hand, it’s important to keep the proportions of the floor and ceiling balanced so the composition looks natural.

A useful guideline is to make the height of the front wall about two-thirds to three-quarters of the total drawing height. This way, there’s enough floor visible to create depth, while the ceiling doesn’t feel too compressed