## Monday, May 28, 2012

### 04 Modeling Nº 66

I have front and side view photographs of a person I want to model a portrait of in oil-clay.

First, I need to scale the photographs so they are as close as can be to each other. In the example below, I try to make a in the front view equal b  in the side view. The overall height of the head is the same as the head I am going to model in oil-clay (in this case, 10 cm.)

Now I can take three measurements from the photographs, namely, the Length, Width, and Height (L, W, H).

Here are the same points on my working drawing.

This is the top view, showing the Internal Diagonal that I want to figure out. The Internal Diagonal is the same as the measurement that I would get if I were to place the points of sculptor's calipers, one point at the chin, and the other point at the notch of the ear.

This is the formula to calculate what the Internal Diagonal (caliper measurement) is, knowing only the Length, Width, and Height measurements from the front and side views of the photographs. In the diagram below, D is the Internal Diagonal (caliper measurement). D is equal to the square root of the  Length squared, plus the Width squared, plus the Height squared.

The Width (b1) is the chin point to x on the front view.
The Length (b2) is the chin point to x on the side view.
The Height (h1) is x up to the ear notch.
The Internal Diagonal (caliper measurement) is from the chin to the ear notch.

Remember that measurements from photographs can only be used as an approximation, to get the rough masses of oil-clay blocked-in. In the final analysis, the eye is the judge.