Curve construction and manipulation.

9.1 Curve menu

9.2 Construction of curves

9.1 Curve menu

A new curve is created with the record function curves from the basic menu. In the curves menu, three functions are available:

• c urve new

...is the new curve function from version 10

• curve replace

...as curve new, but an existing line/ curve to be selected is replaced by a new curve

• curve classic

...is the curve function from version 9 and earlier. It will no longer be available in future Grafis versions.

A curve is shaped with so-called base points and auxiliary points.

Base points are points, which are bound to objects (points or lines) of the construction. Each curve has a minimum of two base points: starting point and final point. Base points constructed with click l, click plg or click rlg can be moved along their base lines. For all other variations, an additional displacement line can be determined by clicking. The following applies to base points:

• Base points are constructed, i.e. bound onto the construction.

• Base points can be moved along an existing dis-placement line.

• In a base point, a direction can be assigned to the curve.

• Base points are indicated by small crosses.

Auxiliary points are points, which are not bound to the construction. The position of auxiliary points is calculated relative to the zero curve. The zero curve is displayed as a dashed line and generated exclusively on the basis of the assignments of the base points. Auxiliary points are determined by their relative position to the zero curve between two adjacent base points.

9.2 Construction of curves

Step-by-step guide

• Basic menu -> curves -> curve new

• Construction of starting and final point of the new curve

• Set the base points along the curve. This way, the curve is moved with the base points during grading:

  • Insert points

• Bind points: the point becomes a base point.

• If the curve is to have a particular direction in a base point, it is advisable to construct the direction at this stage with Set direction or Direction start/ final. The direction can be fine-tuned subsequently at any stage.

• I nsert further auxiliary points for fine-tuning of the curve with Insert points

• If necessary, base points, auxiliary points and directions can be deleted.

• Support during curve construction via the functions of the right menu strip:

• raster

• various display options

• redo and undo the steps within the curve construction.

• End or Abort to quit the curve construction

End curve construction

With end in the menu on the right, the curve is deposited in your construction. Abort in the menu on the right rejects the current changes to the curve. The curve becomes a straight line from starting point to final point.

Self assessment questions

1. How to construct new curve?

2. How to change the shape of curve?

3. What are the base points of curve?

4. What are the auxiliary points of curve?

5. How to end curve construction?

Reference:

©Friedrich: Grafis – Textbook Part 1, Edition 2008, Chapter 9, 2-7p.p.

Lecture 10