Placeholder Dimension?

[durahl]

Greetings!

I'd like to Dimension a Cross whose Leg length to width dimensions are based purely on a Ratio without Values.

So that Width would be 5:9 to that of the Length. Is there a way to define the first Dimension as a literal X and the second Dimension as 5:9 of X? 🤔

Essentially Something like this ( spliced together from two Screenshots 😞

[TheCADWhisperer]

@durahl 

Why not assign a placeholder value for x (it can always be edited later)?

[jeff_strater · Accepted solution]

the usual way of doing this with a parametric system is to define a user parameter for length, and then use an equation: length * 5 / 9 for the width, as @TheCADWhisperer said.  However, if you truly don't want to enter length, just define a Driven dimension for the length, update the equation to reference it, and you can interactively drag the length and have the width update:

[durahl]

The reason I couldn't use a predefined Value was because of the already in place 5mm Constrain between one of the Corners and the circumference of the Circle - Whatever Value was set had to be the correct one which I wouldn't know beforehand.

Doing it like suggested in your Video will work for me but what I really want was a more intuitive method where I could really just type in X into the first Dialog Box and X / 9 * 5 into the second one with Fusion taking over. As of now - with my example - I'd first have to define the hard 5mm Corner to Tangent Constraint, then arbitrarily define the Width Constraint, following the creation of an Over-constrained Driven Length Constraint, just to follow up with reEditing the Width Constrained based on the now established Length Constraint 🤯 Without the hard defined 5mm Constrained I wouldn't be seeing the option to turn a then nonOver-constrained Length Constraint into a Driven one ( the Option to convert it was missing so the only way to get it to be driven was by having it be defined as Over-constrained by the time it was created ).

Pretty sure by the next time I need to sketch something like this based on ratios I've forgotten how to do it 😑