Scale Law

Contour scaling can be defined by a table or by using auxiliary geometry. Let's review all approaches. When sweeping the contour, one can define an additional law for scaling the contour with respect to the origin point of a section coordinate system or any other point in the space, related with the section coordinate system and moving together with it. The scale factor can be specified in a table or by using an additional guide.

Scale by Table

The table appears as a set of trajectory points, with a fixed value of the scale factor entered against each point. Scaling is defined with the help of the controls on the tab Scale of the parameters window. The way of defining parameters is the same as that of defining the twist by table. When defining the scaling law by table, manipulators and decorations are also displayed in the scene.

In the rest of the points along the trajectory path, the value of the scale factor is interpolated by the system automatically.

The scale law as well as the twist law can be defined with a graph. Use button in the parameters window for this purpose. The range of definition by X is 0-100 corresponding to the percentage from the length. The function values must be positive only. See more details on operations with graphs in chapter Graphs.

Additionally, the parameters window has a pulldown list for adjusting parameters of scaling with respect to the attachment point.

Scaling guide and scaling point

Any object with wire geometry can be used as a guide. The system can be tuned for selecting a certain type of objects by using the pulldown list behind the option. The selected object will be highlighted in green (by default). Once the guide is selected, a combo box in the parameters window becomes available for selecting a scale vector defining option.

You can select any objects suitable for defining a 3D point.

Once the reference point is selected, a combo box becomes accessible in the parameters window for selecting an option of scaling with respect to the point. You can choose from the three items – Retain size, Retain distance, Change size and distance.

When using an additional scaling guide, the scale factor of an intermediate section is calculated as a ratio of the vector length in the current point of the trajectory to that in the first section. The methods for calculating auxiliary vectors by additional guides are described in a separate topic (see below).

The scaling point, together with the scaling method, allows additional control over the shape of the body.

When using a scaling reference point, the way of scaling the contour with respect to that point can be one of the following:

•Retain Size. Scale the distance from the origin on the trajectory to the reference point, keep the contour snapped to the reference point, but don't scale the contour;

•Retain distance. Scale the contour only; don't change the distance between the reference point in the trajectory;

•Change size and distance. Scale both the contour and the distance to the reference point.