# Constrain by surface area in Fusion 360

I'm trying to create a sketch that is constrained by surface area.

In my model I have a relatively irregular, flat area that I would like to constrain by area so that it never exceeds a certain number. There are a lot of other constraints for angles, lengths, points, lines and the area of a surface is also always available in the properties. As a rather new person to Fusion 360, it feels logical a constraint by surface area should be possible.

Am I missing something or is there a good reason why this constraint doesn't exist?

• Do you have Printer Settings where you can control the Printer Shape? Does this do what you want? Sep 29 '20 at 11:26
• Although this question is not off-topic according to our help section, you might get more response from the Fusion 360 community.
– 0scar
Sep 29 '20 at 11:26
• Fair enough. Does that mean we should close this one? Sep 29 '20 at 11:43
• I am testing some things, but the question is good - even though I don't really see an application Sep 29 '20 at 17:55

After some testing, Fusion does have a category to put in an Area parameter [edit -> Parameters ->] for Area that takes measurements in acres and circular mil but no useful measurements such as square centimeters or square inch. One circular mil is defined as a circle with a radius of 1/1000 inch, or 0.0254 mm, for an area of $$5.067×10^{−4}\text{ mm}^2$$.

However, defining the area of an item isn't (currently) straightforwardly possible: areas are not defineable, and with the obvious lack of possible parameters (square metrics and anything but super tiny or super huge) it doesn't seem to be planned. The best you can do is for bodies that you know the formula for the area in the following fashion:

Here, the left measurement (d2) is 1 mm. The parameter area is 10000 circular mil. Since we know A=d1*d2, we can go A/d2=d1 for a rectangle.

• Yeah, noticed that too and it's confusing as the area is a calculated property on any surface you select. While it's not really solving my issue I think it is the best answer I can expect. Thx :) Oct 9 '20 at 6:25