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发表于 2010-10-12 18:38:18
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公式本身的应用其实比较简单，关键是在建模的时候自己要理清楚逻辑关系，为什么要用公式，为什么这么用公式要先理清楚。
对于公式本身，Revit中可以使用算术运算和三角函数运算；
Addition— +
Subtraction— -
Multiplication—*
Division—/
Exponentiation—^: x^y, x raised to the power of y
Logarithm—log
Square root—sqrt: sqrt(16)
Sine—sin
Cosine—cos
Tangent—tan
Arcsine—asin
Arccosine—acos
Arctangent—atan
e raised to an x power—exp
Absolute Value—abs
同时也可以运用条件语句，来做一些条件上的判断，贴一段英文的帮助吧；
A conditional statement uses this structure: IF (<condition>, <result-if-true>, <result-if-false>)
This means that the values entered for the parameter depend on whether the condition is satisfied (true) or not satisfied (false). If the condition is true, the software returns the true value. If the condition is false, it returns the false value.
Conditional statements can contain numeric values, numeric parameter names, and Yes/No parameters. You can use the following comparisons in a condition: <, >, =. You can also use Boolean operators with a conditional statement: AND, OR, NOT. Currently, <= and >= are not implemented. To express such a comparison, you can use a logical NOT. For example, a<=b can be entered as NOT(a>b).
The following are sample formulas that use conditional statements.
Simple IF: =IF (Length < 3000mm, 200mm, 300mm)
IF with a text parameter: =IF (Length > 35', “String1”, “String2”)
IF with logical AND: =IF ( AND (x = 1 , y = 2), 8 , 3 )
IF with logical OR: =IF ( OR ( A = 1 , B = 3 ) , 8 , 3 )
Embedded IF statements: =IF ( Length < 35' , 2' 6" , IF ( Length < 45' , 3' , IF ( Length < 55' , 5' , 8' ) ) )
IF with Yes/No condition: =Length > 40 (Note that both the condition and the results are implied.) |
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