T-FLEX Parametric CAD. Fundamentals. 2D Design

Getting Started
Typically, nodes are created at construction line intersections.
The nodes are directly involved in defining the parametric model that will drive other construction entities.
Examples of such situations are: a line passing through a node at a specified angle to another line, a circle
passing through two nodes, etc. Modifying the location of one of the lines defining the node will cause the
node to adjust. This change will propagate on other construction entities related to the node. The nodes are
also used for defining the ends of the graphic line segments and other graphic entities.
Besides the nodes that are defined by intersections of pairs of construction lines, T-FLEX CAD supports
several other types of nodes whose creation techniques are described below. For now, let’s consider only the
difference between the “snapped” and “free” nodes.
The typical technique of creating a parametric model implies creating nodes at construction line
intersections. This technique is called “constrained drawing mode”. While in “constrained drawing” mode,
creating a node at some location will undergo automatic snapping to the nearest to cursor pair of construction
lines and their intersection.
Creating “free” nodes is a special drawing technique used in non-parametric drawing, such as sketching. This
will further be referred to as “free drawing mode”. While in “free drawing” mode, the nodes are created
exactly under the cursor, without snapping to construction line intersections.
The “constrained drawing” mode is indicated by the icon of the T-FLEX CAD automenu.
The “free drawing” mode is indicated by the icon of the automenu. Switching between these modes is
done with or by picking the respective automenu icon.
The recommended drawing technique is using the “constrained drawing” mode.
Avoid using mixed modes on the same drawing, as this may cause errors in
parametric modifications of the drawing.
Fixing Vector is a construction entity that helps defining the location and orientation of the
drawing that is used as a fragment in an assembly drawing.
Connector is a construction entity that provides a placement reference for 2D fragments.
Besides the geometrical location (the origin of the coordinate system and the axes orientation),
a connector can keep additional data (both the dimensional and non-dimensional) that is
necessary for “plugging in” the 2D fragments. These data are stored as a list of named values
that can be either fixed constants or modifiable parameters. As for the parameters, their names
within the connector are significant in the following way: assigning same names to the
external parameters of the element to be connected makes these parameters assume the values
of their counterparts in the connector.
Graphic Entities
Graphic Lines are the lines constituting the actual drawing of the
drawing. Graphic lines include straight segments bound by a pair of
nodes, full entities, such as circles, closed splines and so on, except for
the infinite straight lines, and the portions thereof bound by pairs of
nodes, also splines through nodes.
The graphic lines may be of various types (main solid, thin solid,
dashed, dotted etc. They are snapped to nodes and construction lines.
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