What is the significance of the first lines drawn in a sketch?

The first lines drawn in a sketch are crucial as they establish the main proportion of the sketch, which interrelates various dimensions and create a basic framework for further detail. Drawing initial lines to represent the scale and proportion ensures that the following elements fit well within the overall design and can accurately represent the object being sketched. This foundational step allows for proper alignment and perspective, making the remaining details more coherent and integrated.

While outlining the object and enhancing visibility are important, the initial focus is on getting the proportions right, which supports clarity and accuracy as additional details are added. The choice concerning showing all views for projection or making lines very bold, while relevant in certain contexts, does not address the primary purpose of those first lines in establishing basic proportional relationships.