Create formulas
You can create formulas that Tekla PowerFab uses to calculate values. For example, you can create a formula to define the size of an angle used in a parametric assembly or to define the cost of an estimate extra.
Access Formula dialog box
 For estimate extras, do the following steps:
 a. Go to .
 b. Click the Formula button on any of the tabs.
For more information, see Create estimate extras.
 For parametric assemblies, do the following steps:
 a. Go to .
 b. Select a parametric assembly and click Open.
 c. Click the Formula icon on the right side of any input field.
For more information, see Create and manage parametric assemblies.
 For adjusting labor codes, do the following steps:
 a. Go to .
 b. Click the Labor Code Maintenance ribbon tab and select Formula Maintenance.
 c. Click Edit Formula.
For more details, see Add, modify, and delete formulas in Adjust labor codes
 Standard Variables: The properties of a material item
 Add Variable: Any previously added variables related to the parametric assembly or the estimate extra
 IF / THEN / ELSE / ENDIF: IF/THEN/ELSE/ENDIF statements
 The CEILING, FLOOR,
ROUND: Rounding functions.
 CEILING always rounds up.
 FLOOR always rounds down.
 ROUND rounds up at half and down by less than half.
 Several trigonometry functions, such as SIN, COS, and HYP.
Example formula: Calculate the cost of an estimate extra
In this example, we want the estimate extra to add a cost of $100 if the length of the item is less than or equal to 40'. If the length is greater than 40', the added cost should be $150.
In this case, we need the following formula:
IF ([Length] <= 40') THEN (100) ELSE (150) ENDIF

In the Estimate Extra dialog box, select the Cost Expression option, and click Formula.

In the Formula dialog box, click the IF / THEN / ELSE / ENDIF button.

Go to the parenthesis after IF.

In the Additional Variables list, select Length.

Click Add Variable.
[Length] appears inside the parenthesis after IF.

Enter a space after [Length].

After the space, type <=40'

Go to the parenthesis after THEN.

Type 100

Go to the parenthesis after ELSE.

Type 150
The formula is now ready.

Click OK to close the Formula dialog box and use the formula in the estimate extra.