Pro/Engineer April 2005 Tip-of-the-Month
Power Tools: Curves by Equation
Our tip this month highlights a very powerful, though less used, function of Pro/E. As a tool, creating a datum curve from a mathematical equation can be very handy.
Why? We'll discuss that later. First, to create a Curve by Equation:
Well, it appears functionality is the same in WF2, so back to equations ......
The equations make each of the 3 variables (X, Y, Z in Cartesian Coordinates) independent of each other and based on "t" which Pro/E will vary from 0 to 1.
So, a simple math equation for a parabola, for instance, that is normally written as:
That's the simple part. Now, how do you get control of the equation so you don't have to Redefine it to modify the values?
This requires another feature (or features) for the controlling values -- like a value of another feature -- like a Relation. Just change the constants in your equations to be parameters defined elsewhere in your model.
TIP: Create other datum features (like offset planes or curves) then use the dimension values of those to drive your equations.
In the equation example below, a datum plane was created as an offset from a default plane, with a value of 3. The datum plane offset value has the parameter name d0, so the 3 of the equation x=3*t^2 is simply replaced with d0 making x=d0*t^2.
(You can find those parameter names by showing the values (like with Modify) then use Info > Switch Dimensions. The parameter names show instead of the values.)
Note: Do not use the & symbol with the parameter names like in equations or drawings. Why is it different? Just another inconsistency.
For more control and to really use the available power, expand the above concepts to all the equations. The example below shows the curve generated from the following equations:
Note: that in the X-Y plane, the curve is a parabola, in the Y-Z plane, the curve is a segment of a sine wave, and in the X-Z plane, the curve is a combination. (The X-Y plane is shown in grid.)