SolidWorks 2010 Bible

Part II: Building Intelligence into Your Parts

In practice, you could use it like this:

IIF(x>5, x-1, x+1)

which reads, “if x is greater than 5, then subtract 1 from x; if not, then add 1 to x.” One of the

reasons why this is considered a parlor trick is that this function causes the value of x to oscillate

between two numbers (depending on the number that it starts with) with each rebuild. It may be

difficult to imagine an application where this sort of behavior would be desirable, but when you

combine it with a macro that simply rebuilds a model a number of times, you can use it to create a

certain animation effect.

On the CD-ROM

A simple example of the IIF function can be found on the CD-ROM with the filename Chapter 9

Oscillate.sldprt. The equation is shown in Figure 9.9. n

FIGURE 9.9

An equation using IIF

Tip
You can find some great examples of this function at http://www.mikejwilson.com, along with many other
extremely creative examples of SolidWorks modeling. The model on this site called Ship in a Bottle.
sldprt also includes a macro that will rebuild the model a certain number of times, which is useful for
animations that are created in this way. n

SWITCH .......................................................................................................

The SWITCH function enables you to have a list of relationships with associated values. The value

of the first relationship in the list that is satisfied is returned by the SWITCH function. For example,

switch (x>2, 1.5, x>1, .5 x<1, 2.5)

reads as follows: “if x is greater than 2, then the answer is 1.5; if x is not greater than 2 but greater

than 1, then the answer is .5; if x is less than 1, then the answer is 2.5.”

As you can see, this function does not cover all situations, but it does create a condition where the

value cycles through three different numbers in a specific order. Is this useful? Possibly. Again, the

main application for this function would be a simple animation for changing the size or shape of

SolidWorks components that cannot be changed in other more conventional ways.