T-FLEX Parametric CAD. Fundamentals. 2D Design

Fundamentals. Two-Dimensional Design
A Few Tips on Creating Graphic Lines
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It is not recommended to use the action for defining the start node of a graphic entity where there are
more than two intersecting construction lines. This is because the node may get created at unintended lines
intersection.
In the special case of two or more coinciding nodes, use an appropriate option for selecting construction
entities (,,,). First, specify the construction entity to underlie the graphic one, and then
either select the node, using the option, or specify the intersecting entity, depending on the situation.
It is a good idea to initially create a node at the intersection of construction lines, using the command “N:
Construct Node”. In this way, you can precisely specify what lines intersection to use for the node
creation. Later, when applying the graphic line, this node can surely be selected using the option.
Consider a simple example illustrating the approach. There are several construction lines on the drawing
below. Line 1 is constructed vertical, parallel to the Y axis, line 2 is a horizontal, parallel to the X axis, line
3 is constructed parallel to line 2, and, finally, circle 4 is constructed with the center snapped to a node,
tangent to line 3. Now, try to apply a graphic arc using the option. Note that the created node will
not necessarily snap to the intersection of the line and the circle. The node may actually be, for instance, at
the intersection of lines 1 and 3. In this case, the circle can’t be selected for creating an arc.
A properly built model helps avoid annoying errors. If a node is supposed to be on the intersection of the
circle and the line, then it ought to be constructed as such.
Basic Rules of Graphic Line Creation
The user is encouraged to follow a few rules when creating graphic line entities:
To avoid errors when creating a parametric drawing, use the option for applying graphic lines. Do not
use the option if there are more than two construction entities intersecting in one point.
If there is a selected node, then it will be used as the start for a graphic line.
If a node is selected and user attempts to select a construction line entity, it has to be a line passing through
the selected node.
If a node and a construction line are selected, and the user selects another construction line, then a graphic
line will be created, starting in the selected node and ending at the intersection of the selected lines.
If two construction entities intersect in more than one point (for example, a line and a circle), then the nearest
intersection is selected to the graphic cursor location at the time of pressing the option key.
If selecting a construction line entity results in nothing, that means, the lines do not intersect and the graphic
line can’t be created.
Using Grid in “Free” Drawing Mode
If snapping to grid is turned on, then the start and end nodes of the graphic line will be snapping to nearest
grid knots. The grid parameters can be defined using the command “Customize|Grid…”. The grid can be