# Thread: Equation in SW 2010

1. ## Equation in SW 2010

Hello,
Doing a series of sound tubes on a instrument and need an equation that will adjust one end of tube but then add the change difference to the other end, weither I subtract or add. Volume of air movement needs to stay the same. The sample jpg. I've attached is just one of 10 tubes.

Thanks

2. From how you've described it, the total leg length will be constant. So, L2 = 39.79 - L1. That is if you are changing each of the 10 tubes individually and are doing so by directly changing the dimension in the path sketch.

If you were looking for something more complex, you'll have to describe how you're doing what you're doing and what is lacking in the current solution.

Or, are you unsure of how to add the equations to the sketch?

3. Each tube will be adjusted separately if need be. I just wanted to have the ability to adjust the long leg and the short leg will be adjusted to compensate the change weither a plus or minus. Owner wants to design a new style instrument smaller and this equation will help position height adj.. and do it directly in the sketch path.. unless something better..
Example. If the longer leg needs to be shortened say by 1.00 in. shorter than it has too be add to the shorter leg. As I mentioned volume in tube needs to be the same. As far as equation I dont know how to write it. Does the reference geometry need too be named prior to the equation? This is new to me..
Thankyou for response

4. OK, this is pretty straight forward.

Edit the sketch that defines the path of your sweep.
If you have not done so, add linear dimensions to each leg.
On the top menu bar, click Tools>Equations... The equation dialogue box should open.
Click the dimension for the short leg (you may have to move the dialogue boxes around to uncover the dimensions). You should see "D1@Sketch1" or something similar in the equation box.
Type in "=39.79-" (without the quotes...and with whatever value your project requires).
Click the dimension for the long leg.
Click "OK" at the bottom of the "Add Equation" box. Dialogue box should close.
Click "OK" at the bottom of the "Equations" dialogue box. Dialogue box should close.

You should notice a sigma symbol next to the dimension on the short leg. This tells you that its value is driven by an equation. If it was done correctly, when you double-click the long-leg dimension and change it, the short leg should change in the opposite way by the same amount.

5. ## Thanks !!

I did as per direction and it worked fine. attched jpg shows difference. End of week I will be working with R&D to configure tube placement and this equation will help alot in time. In an earlier thread you made suggestion to using L1-L2, would there be another approach to an equation ?

6. ## SW Equation

hi'ya jersycnc, check out SW zip, look thru the tree if need be, if I understood correctly this is the function you wanted. If you want I have a 40Mb vid but I can't load it here I can e-mail if you need - kman

See 2nd SW file