Modeling involves numerous concepts such as transformations, curves, surfaces, primitives, and others. The following paragraphs will discuss these concepts.
Modeling Tools are solidThinking main methods to create new objects (Actions) or modify existing ones (Modifiers). The Modeling Tool usually has parameters that define how the object has to be created or modified.
The Action Modeling Tool creates the resulting object from the input parameters. Once the Action has started, it remains active for the whole life of solidThinking. This means that the object created is not static. Parameters are maintained and a link is set between the resulting object and the Action. When you change a parameter, the resulting object is modified accordingly.
Parameters can be of various types: integer numbers, floating-point values, 3D coordinates, a number of individual flags and even other objects. The Extrusion Modeling Tool, for example, accepts as input a profile curve (object), an extrusion direction (3D coordinates) and an extrusion length (floating-point value).
When a parameter is an object, an interesting effect occurs. The source object can be a result of an Action itself, then two actions appear in sequence. Modifying a parameter in the first Action causes its resulting object to change. The resulting object can be a source object of another Action. When the object changes, the Actions for which it is a source are notified that the parameter (the object) has changed. They perform the necessary calculation and modify their resulting object accordingly.
This relationship is called Construction Tree and it is a fundamental structure in solidThinking. The Construction Tree allows for a complex object to be created while any parameter in the tree can be adjusted at any time. When a parameter changes, all the actions down the tree are notified and re-evaluated, propagating the change along the tree.
Let's now take a look at a very simple example as to how this works. Choose the NURBS curve action, and draw a simple profile as below.
Create a revolution surface by selecting the Lathe surface action (if you want to confirm default values you can either press Enter when you are prompted to insert parameters or press Ctrl + Enter to skip all prompts).
Now, select the starting profile by picking it either with the mouse in any view, or from the browser (just select Curve #1).
Choose the Edit mode to make the program display control points of the profile curve. Now, click any control point you want to modify and drag it.
Any modification of the starting profile interactively modifies the revolution surface. You can choose the Shaded view mode by just clicking the S icon on the title bar of the view.