Author: Ton Lecluse 

    Drawing in perpective



The construction box
Plane geometry
Investigating a section
Investigating a function
Drawing in perspective
A probability tree
The calculator
Getting a taste
Back to start

  Geocadabra supports all drawing methods involved with three-dimensional objects:

All parallel projections, just like you usually find them in books on mathematics;
Central projection (= drawing in perspective), the same as when an object is photographed.

To give you somewhat of an idea about what drawing in perspective entails, we will use a pre-drawn, simple picture of a little house.

Start up Geocadabra and choose file, open.
Now open the demo folder and select the file that is titled house with windows and door. A small house,
    drawn in parallel perspective, will appear.

Click on the drawing method perspective in the toolbar. The house will now be drawn in perspective.

The demo version does not support all commands involved with drawing in perspective. For instance, the horizon and lines to vanishing points will not be shown. However, the following is possible:

Right-click on the button. You can now change the viewpoint by pressing the left mouse button and dragging the mouse into the desired direction. The drawing will move along with your mouse. 

You can also right-click a line segment. A menu will appear allowing you to rotate the object around the axis you just selected. (See: Sections). You can now watch what happens when you rotate an object around one of its axis in perspective: when the house comes closer it will become bigger and vice versa, just like in the movies.

Experts only: if you left-click the  button a screen will appear allowing you to control the camera position as well as the direction it is pointing in. The results of your adjustments will become visible instantly.

The CDROM features a complete course on perspective.

The contents of this course are based on the zebra booklet ‘Perspectief, hoe moet je dat zien’ by Agnes Verweij and Martin Kindt (Epsilon Uitgaven Utrecht, ISBN 90-5041-052-9). All notes and terms are directly taken from this booklet.