Dynamic Block - Variable constraints and fixed values - is this possible?

[williamt7RZKF]

Good morning Hive Mind, 

I'm working a developing a dynamic block for cut parts that are used in shipbuilding. 

what I'm trying to do is make a bracket length proportional to the depth of the web of the cut part.  but with a fixed minimum value. 

The rule is simple, its bracket length = 1.5x the depth of the web, so a 100mm web depth would give a 150mm bracket length. the issue is the bracket length cant be less than 100mm. for example when you have a 50mm deep web the rule would state that the bracket length would be 75mm, which would not give enough weld attachment. 

I have started with a list option on the bracket length so it can't be smaller than required, but I would like to add little more intelligence to the block. 

please see the screen shots for an instance where it is used, the current dynamic block, and the two areas that I would like to communicate to each other. 

there are several other issues with but I'm stumped on this one at the minuet

Thank you for any hints and tips

Will 

[CGBenner]

@williamt7RZKF 

Welcome to the Community, Will.  Thank you for the detailed question and for sharing the file for the experts to look at.  Good luck!

[j.palmeL29YX · Accepted solution]

For the bracket length I'd use a value 

Bracket_length=max(1.5*web_depth,100)

[j.palmeL29YX]

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@williamt7RZKF wrote:

there are several other issues with 

 

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Some suggestion: 

BTW: A lot (all?) of your construction lines may/should be deleted. You don't need it. 

An example result attached. 

[williamt7RZKF]

Good morning Jürgen, 

thank you very much for your solution, it works perfectly. as I'm just getting started on Dynamic blocks and constraints, it look any constraint could be written in the same format as an excel calculation, would this be correct?

thank you also for your suggestions, I have added them in to the dynamic block. 

Hope you have a good week.

Will

[j.palmeL29YX · Accepted solution]

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@williamt7RZKF wrote:

... constraint could be written in the same format as an excel calculation, would this be correct?

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F1 (Help): 

Use Operators in Expressions

Dimensional constraint parameters and user variables support the following operators within expressions:

Operator	Description
+	Addition
-	Subtraction or unary negation
%	Floating point modulo
*	Multiplication
/	Division
^	Exponentiation
( )	Parenthesis, expression delimiter
.	Decimal separator

Note: With imperial units, the Parameters Manager interprets a minus or a dash (-) as a unit separator rather than a subtraction operation. To specify subtraction, include at least one space before or after the minus sign. For example, to subtract 9" from 5', enter 5' -9" rather than 5'-9".

Understand Precedence in Expressions

Expressions are evaluated according to the following standard mathematical rules of precedence:

1. Expressions in parentheses first, starting with the innermost set
2. Operators in standard order: (1) unary negation, (2) exponents, (3) multiplication and division, and (4) addition and subtraction
3. Operators of equal precedence from left to right

Functions Supported in Expressions

The following functions are available for use in expressions:

Function	Syntax
Cosine	cos(expression)
Sine	sin(expression)
Tangent	tan(expression)
Arc cosine	acos(expression)
Arc sine	asin(expression)
Arc tangent	atan(expression)
Hyperbolic cosine	cosh(expression)
Hyperbolic sine	sinh(expression)
Hyperbolic tangent	tanh(expression)
Arc hyperbolic cosine	acosh(expression)
Arc hyperbolic sine	asinh(expression)
Arc hyperbolic tangent	atanh(expression)
Square root	sqrt(expression)
Signum function (-1,0,1)	sign(expression)
Round to nearest integer	round(expression)
Truncate decimal	trunc(expression)
Round down	floor(expression)
Round up	ceil(expression)
Absolute value	abs(expression)
Largest element in array	max(expression1;expression2)
Smallest element in array	min(expression1;expression2)
Degrees to radians	d2r(expression)
Radians to degrees	r2d(expression)
Logarithm, base e	ln(expression)
Logarithm, base 10	log(expression)
Exponent, base e	exp(expression)
Exponent, base 10	exp10(expression)
Power function	pow(expression1;expression2)
Random decimal, 0-1	Random

In addition to these functions, the constants Pi and e are also available for use in expressions.