- Free ruler and compass drawing software how to#
- Free ruler and compass drawing software software#
One simple answer is that they are such basic tools to make and use.
Many drawing programs do not make clear where the mid-line of the outline is with respect to the theoretical shape being drawn. Ellipses and circles are especially likely to have this problem. 
Some drawing programs are not designed to simply shade the area of a shape they insist on outlining the shape in black as well. Free ruler and compass drawing software software#
Most drawing software does not have any feature for calibrating print outs. Paper sizes can vary by a fraction of a percent from day-to-day.
Rasterized screenshots and printouts are either quantized enough to be less accurate than a straight-edge, or are fuzzy enough to be less accurate than a straight-edge. Instead they draw "4-circle ellipses" that are actually 4 pieces of regular polygons. Many drawing programs only pretend to draw ellipses. They actually draw regular polygons instead. Many drawing programs only pretend to draw arcs and circles. Floating point numbers are quantized, and not especially consistently. And drawing programs do have accuracy limitations, which are sometimes worse than those of a straight-edge and compass. The accuracy limitations of a straight-edge and compass are more obvious than the accuracy limitations of a drawing program. Now to answer your question: if you don't use a compass but instead you use a computer program to draw circles and arcs, how will you then pass the most important property of a circle to your students: not the fact that a circle is round but the fact that it consists of equidistant points? If I had learnt to use the compass in two ways (drawing a circle and measuring distances), I might have realised earlier that a circle is a set of equidistant points directly, without needing to pass via the "round" comprehension, which is for a student something which reduces the understanding of the matter. This, obviously, is right, but there also is another use of the compass, which is to estimate a distance between two points: this can be seen in movies about ancient ships, where the captain holds a ruler in one hand, and uses the compass to measure multiples of a certain distance along that ruler.Īs I had not learnt to use the compass in that way, I always thought that a circle is something round, and during later education, I first needed to pass via that "round" comprehension before realising that the definition of a circle is a list of points at an equal distance from a central point. I would like to express here a personal complaint, which will also answer your question: as a child I learnt to work with a compass and straightedge, but there was a great drawback: I learnt that a compass is used to draw circles. These are just a few specific ideas that came to mind - the general idea is to use the constructions as a tool to teach logical and geometric reasoning.įor a case study in how not to teach geometric constructions - which may highlight some pitfalls to avoid - see Schoenfeld 1988, 'When Good Teaching Leads to Bad Results: The Disasters of "Well-Taught" Mathematics Courses'. This could also be used to illustrate how subtle changes to axioms can have a major impact on what's provable/constructible (like how doubling the cube is impossible with compass and straightedge, but becomes possible as soon as you can mark lengths on the straightedge). Free ruler and compass drawing software how to#
However, geometric constructions can still serve useful educational purposes now, because it's a simple axiomatic system that can be a good way for students to learn to connect geometric intuition with careful, precise reasoning.įor example, once students have learned how to construct bisections of angles, one can ask them to try to trisect an angle, and use this to introduce the concept of an impossibility proof.
This method of axiomatic construction was first studied for historical reasons that perhaps aren't as relevant now - having to do with the "synthetic" style of axiomatic geometry used by the Ancient Greeks, as opposed to the "analytic" style more popular in modern mathematics (e.g., Cartesian coordinates). The accuracy of the actual drawings is basically irrelevant (as long as it's not so sloppy that it impedes visualization) - the point is that they can prove the accuracy of the idealized constructions. The point of compass-and-straightedge constructions is for the students to get experience reasoning about axiomatic systems.
0 kommentar(er)
