Constructing a perspective of a free-form object, or a bunch
of misaligned objects is trouble, and should be done in a computer with a CAD
and rendering program. If however you have a design that is regular and
rectilinear, there are simple rules that will get you there without a lot of
work.
A tiled floor of equal sized squares creates a repeating
pattern across the width and depth of a room.
But, it also creates a regular diagonal pattern which
establishes vanishing points to the left and right of the centered one point
vanishing point. If the grid consists of squares, then you have set up a
diagonal system that can be used to establish any floor plan shape.
A grid of regular lines on an elevation can be used in the
same way.
In the photo above the grid is not made up of squares, so a
number of diagonal vanishing points are possible. If you know the relative
distances of vertical and horizontal spacing you can set up a measurable grid.
In any case such a diagonal set of perspective lines will give you a grid to
hang your design on.
Oh, alright. A short bit of graphic instruction would help
here…
Draw a square, and then draw a horizon line 2 or 3 “squares”
above. Draw lines from each corner of the square to the horizon line
immediately above it. Strike a diagonal (dotted white line) to a vanishing
point a reasonable distance to the side of the horizon line (You can do this by
eye; a post on distortion will follow). By drawing a horizontal line where the
diagonal crosses the lines connecting the square to the horizon line above you
establish the top of the cube (white with cross inside). Carry vertical lines
(green) down to the lower lines going to
the horizon and you establish the bottom of the cube (red with cross inside).
This last step can be done or checked by striking a line to the diagonal
vanishing point from the lower right corner of the original square.
Fill in the cube with solid white and you have a cube facing
you in one point perspective. Simple, dull, boring and surprisingly useful.
While a circle drawn in the front elevation is a true
circle, a circle on the top (which is receding in perspective) is an ellipse.
The cross helps to place the ellipse which I use a template when drawing in the
ancient mode.
It is quite easy to multiply the cubes in any direction. The
diagonal vanishing point defines all subsequent cubes.
As said before, the front face of the cube (or any multiple
thereof) is a measurable surface easily marked with an elevation drawing.
More importantly, any front face is equally measurable and
ready for an elevation marking.
The cubes can be extended left, right, up or down. The only
limitation is distortion.
But here is the fun part of the endless cube. By striking
diagonals to the vanishing point from the centers of each side you create a…
cube seen in two point perspective! Yes, you will have to adjust the height to
get it right, but practice will educate your eye.
Drawing elevations on the faces of this new cube is a little
messy, but again, with practice and a good eye you can reproduce a two point
perspective without doing a complete layout.
We’ve dealt exclusively with cubes up until now. What about
cylinders? Well, we have already marked circles on the sides of a cube, so it
is simple to consider the circles as the top and bottom of a cylinder.
Fill in the form, and voila!
Shade and shadow are useful to make the cylinder believable,
but that is for another time and another post.
Caveats, caveats, and excuses…
Knowing the relationship between one point and two point
perspective is very useful when working on something simple, or sketching an
idea. If you want to produce a serious perspective, or want to see what a form
looks like from all angles, go immediately to your computer. My reason for
writing these post on perspective layout is not to replace the computer, but to
supplement your knowledge about what is happening in the computer. Too many
architects and designers have never worked out a perspective layout, but have
gone straight to the computer. In my experience a little hands on work is
necessary to make the most of the computer programs available.
NOTE: These posts are NOT meant to be a tutorial on
one-point perspective. There are plenty of websites that do that. I want to
illustrate some of the interesting examples, and point out the major problems
and opportunities out there.
Perspective - Three Point Perspective- Hand & CAD
Other posts on Perspective:
Perspective - Two Point Perspective -
Distortions & ComplicationsPerspective - Three Point Perspective- Hand & CAD
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