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Relative dimensioni (by Gianluca)
Hello everyone,
I need to draw a prototype of which I don't know the dimensions yet but only the ratios.
Is it possible to use "variables"? I'll explain better with the pictures because I don't speak English well.
In image I have established a temporary dimension between the wheel axles. When I click on it, a name "c00a-pt-pt-distance" also appears.
In the next image I'm building a piece that needs to be half the previous size. I tried to insert c00a-pt-pt-distance/2 as a value but obviously it is the wrong way because it gives an error.
How can I set dimensions relating them to a single part?

Wed Jan 18 2023, 08:55:39, download attachment Immagine333.png
(no subject) (by Andrew)
Variables is a requested feature, but meanwhile a geometric approach can be used to solve your problem.

By using parallel lines, including multi segment,,say horizontal, allowing vertical end points to keep the same overall length, and reasonable ratio, or n segment length, as a separate line, can be created, with an unsegmented line being used to set the 'master length. That is for your case, a line, and a two segment line will allow you to set the 2 to one ration, and by using the equal constraint, control dimensions in other sketches.

This way, by using multiple segmented lines, any set of ratios can be generated,

This construction can be tucked away in its own group, or in a separate file, and hidden when not needed to select a line an equal constraint in another sketch.

While not as convenient as variables, it is a workable solution to your problem.
Wed Jan 18 2023, 10:01:05
(no subject) (by Paul)
You can use a line length ratio constraint directly between 2 lines. This is similar to an equal length constraint but allows a ratio.
Wed Jan 18 2023, 13:41:27
(no subject) (by ruevs)
Also length difference.
Wed Jan 18 2023, 14:24:33
(no subject) (by Gianluca)
Thanks for the answers. @Paul how?
Thu Jan 19 2023, 09:16:27
(no subject) (by Gianluca)
Paul thanks, I found it. It is not a button but is located in:
Constrain>Length/Arc Ratio (Z)
Thu Jan 19 2023, 09:47:46
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