SolidWorks 2011 Parts Bible - Matt Lombard [53]
Horizontal and Vertical Ordinate Dimensions have the same function as the regular Ordinate Dimensions, except that they only drive horizontal and vertical dimensions, respectively.
Chamfer Dimension is another type of dimension that is only driven and only applied in drawing documents. It works by first selecting the chamfered edge and then selecting the angle reference edge. It produces dimensions like the one shown in Figure 3.31.
FIGURE 3.30
Options for Ordinate Dimensions
FIGURE 3.31
Applying a chamfer dimension
Automatic Relations toggles to enable or disable the automatic creation of sketch relations while sketching. This toggle is also available through Tools⇒Sketch Settings⇒Automatic Relations. Automatic relations help you to create intelligent sketches with less manual intervention. Although using them takes a little practice, it is well worth the effort.
Caution
As with any automatic function, there are times when automatic relations will do things that you do not expect or want. While you are sketching, it is recommended that you watch the cursor and the relations that it automatically applies.
While sketching, symbols appear on the cursor to show that a relation will automatically be created. These symbols have a yellow background and will apply horizontal, vertical, coincident, tangent, parallel, and perpendicular relations. Figure 3.32 shows two situations where automatic relations are applied — a horizontal and a tangent relation.
FIGURE 3.32
Some automatic relations that appear on the cursor
Inferencing in Sketch
Although SolidWorks users (even experienced ones) often confuse Inferencing and Automatic Relations, these functions are not the same. Inferencing refers to the blue dotted lines that display in Sketch mode when the cursor aligns with endpoints, centerpoints, or the Origin. Inferencing does not create sketch relations, with one exception. If both ends of a line pick up the same inference to the same point, SolidWorks will add that inference as an automatic relation.
When the cursor displays a small sketch relation symbol with a yellow background, this means that an automatic relation is going to be applied. If the relation symbol has a white background, the relation is inferenced but not applied as an actual sketch relation. The symbols with the blue (the color may also be green in SolidWorks 2008 or later) background are relations that have been applied to existing sketch entities. The symbols look the same, regardless of background color. Be aware that differences in versions and differences in color schemes can cause these colors to be different on your system.
Table 3.1 shows the symbols for the various inferences, automatic relation cursors, and applied sketch relations. The difference between the three types is simply the background colors: white, yellow, and blue, respectively.
The Fully Define Sketch interface uses sketch relations and dimensions to fully define the active sketch. It enables you to select which types of sketch relations and dimensions will be used to do this. Figure 3.33 shows the Fully Define Sketch interface. Be careful of this icon because it looks almost identical to the Sketch icon.
If you are familiar with older versions, the Fully Define Sketch function was formerly called Auto Dimension and has absorbed the functionality of Scan Equal and Add Relations. This function is very useful when used with imported sketch data. If you do not like the automatic dimensioning scheme, you can at least take advantage of the automatic sketch relations.
Best Practice
The Fully Define Sketch function does not necessarily use the best dimensioning practice for manufacturing drawings or for Design Intent. This tool is best used in situations when baseline and ordinate dimensions are appropriate.
FIGURE 3.33
The Fully Define Sketch interface
Exploring Sketch Settings
In addition to sketch tools, another important aspect of controlling sketches is sketch settings.