To divide a cube in perspective, a fundamental technique involves first drawing the diagonals on all visible planes of the cube. Once the diagonals are in place, you can then make the necessary vertical and horizontal divisions based on the points found using the diagonals.
The Basic Principle
Dividing objects accurately in perspective can be challenging, as standard measurements become foreshortened. A common method relies on geometric principles that remain true even in perspective, such as the fact that diagonals of a square (or rectangle) intersect at its center point. The reference highlights this by stating, "This is the same in perspective," implying the standard geometric rule applies.
By finding the center or other key points on the planes using diagonals, you can then project lines vertically and horizontally to divide the entire form in perspective.
Steps to Divide a Cube in Perspective
Based on the provided information, the process for dividing a cube in perspective can be broken down into these steps:
- Draw Diagonals: On each visible plane of the cube (the front face, top face, side face, etc., depending on your view), draw the diagonals from corner to corner.
- This is crucial for finding the center of each plane.
- The reference explicitly states: "...i need to draw all the diagonals. On all the planes."
- Make Divisions: Once the diagonals are drawn, you can use the points created (like the intersection point at the center) to guide your vertical and horizontal divisions across the cube's planes and volume.
- The reference mentions: "Then make the vertical and horizontal divisions."
Applying Divisions Using Diagonals
Drawing the diagonals helps locate the exact center of a plane in perspective. A vertical line drawn through this center point will divide the plane (and the part of the cube it represents) into two equal halves in perspective. Similarly, a horizontal line through the center will divide it horizontally.
For example, to divide a face of the cube into quarters in perspective:
- Draw the diagonals to find the center.
- Draw a vertical line through the center point, extending to the top and bottom edges of the face.
- Draw a horizontal line through the center point, extending to the left and right edges of the face.
- These lines, combined with the original edges, will divide the face into four equal sections in perspective.
These division lines can then be projected back into the cube's volume to divide the entire cube.
Key Takeaways
- Diagonals are a fundamental tool for finding centers and midpoints on planes in perspective.
- Drawing diagonals on all relevant planes is the first step.
- Vertical and horizontal divisions are then made based on the points derived from the diagonals.
- This method allows for accurate division of the cube's surfaces and volume within a perspective drawing.
