Leonardo Da Vinci
Measuring Tools
To do both of these types of measuring you will need a straight long object that you can hold comfortably in your hand. This can be a pencil, ruler, chop-stick, knitting needle. This tool will act as a line that you superimpose on what you are observing, therefore referencing the two-dimensional picture plane.
Three Rules to Accurate Measuring
1. Keep your measuring arm straight
To use your measuring tool you must hold it at a full arms length parallel to your body. It is very important that you extend you arm out straight, locking you elbow. This limits the variables so you can get a more accurate and consistent measurement.
2. Hold your measuring tool parallel to picture plane
It is important that you hold the pencil parallel to you body and the picture plane. If the pencil tips toward or away from you it will become foreshorten or distorted making it hard to use accurately.
3. Close one eye
You should always measure with one eye closed. This limits you point of view and your depth perception, which is crucial when trying to visualize two-dimensional relationships.
Horizontal & Vertical Alignment
This type of measuring looks at how parts of what you are observing relate to other parts across the picture plane both horizontally and vertically. For example: Comparing the position of the head to the feet. With one eye closed, extend you measuring arm with you tool straight up and down (for vertical alignments) or straight across (for horizontal alignments). Bring the tool into your direct line of vision, superimposing it onto what you are observing. Use the line created by the edge of the measuring tool to observe two-dimensional relationships between and within the things that you are observing.
Measuring Angles
Angles or diagonals appear when a geometric form recedes into space. The best way to measure them is to compare them to a straight vertical or horizontal. This will give you a close estimate. To refine that measurement it is helpful to view the angle like the diagonal of a right triangle. If you find the height and width of its sides you can plot the angle. Plotting out the diagonal using verticals and horizontals is more precise then trying to visually transfer the angle.
Daniel M Mendelowitz
Proportional Measuring
Proportional Measuring looks at how the size of one part of what you are drawing relates to the size of another. For example: Comparing the size of the models head with the height of the model. With one eye closed, extend you measuring arm with you tool straight up and down or straight across, superimposing it onto what you are observing. Choose a section of what you are observing to use as a proportional guide: the height of a head, the side of a table, the distance between two objects. Mark with your index finger or thumb on the measuring tool where this object begins and ends. Use the point or end of your tool as the starting point so that you only have to mark one point with you finger. With you arm still extended compare that measurement with other things around it. If you observe that the width of the shoulders is two times larger then the height head you have established a proportional relationship between the shoulders and the head. Now check your drawing to make sure you have drawn the width of the shoulders two times larger than the size that you drew the head. Remember that you do not want to transfer these measurements in a one to one ratio directly to your paper, but to make the comparisons within your drawings.
