How to Create a Curve by Equation in Pro/ENGINEER

In Pro/ENGINEER you can create a datum curve from a mathematical equation. Below are some examples of how this can be achieved.

First you will need to follow the three simple steps below:

• Insert > Model Datum > Curve . > From Equation > Done
• Select your coordinate system
• Select Cartesian, Cylindrical or Spherical

Equations in Pro/ENGINEER will make each of the three variables (X, Y and Z in Cartesian Coordinates) independent of each other and based on "t" which Pro/ENGINEER will vary from zero to one.

A simple math equation for a parabola, for instance, is normally written as:

x=y^2

In Pro/ENGINEER, an equation must be written for each variable independently, as follows:

x=t^2 (x varies with square of t)
y=t (y varies linearly with t)
z=0 (curve on the x-y plane) (Figure 1)

Pro/ENGINEER evaluates the equation from t=0 to t=1, so, in order to scale the result, just add a scale factor to the equations as follows:

x=3*t^2 (scaling the result by 3) (Figure 2)

Or

x=(3*t)^2

The result will be as if "t" varied from zero to three. (Figure 3)

Additionally, you can displace the curve by adding a constant to the equation like:

x=1.2+3*t^2

And/or, you can change the Z position by making Z equal to a non-zero value, or even an equation of its own. (Figure 4)

Figure 5 shows the curve generated from the following equations:

x=d1+d2*t^2
y=d0*t
z=1+d3*cos(t*400)

You can create an elliptical helix with the below equation:

x=4*cos(t*3*360) y=2*sin(t*3*360) z=5*t (Figure 6)