Goal amount for this year: 2500 USD, Received: 1869 USD (75%)

1. ## PSU formula

Hello

I have created a formula for my LORU and LDR fittings, now I need one for a PSU fitting.
I have been working on the formula and it works with NESTED IF STATEMENTS.

I do have a problem though. It moves in the wrong direction.

When I create a formula like this: if(D1 = 80 mm, 50 mm, if(D1 = 100 mm, 80 mm, 100 mm)) the right PSU size appears but it moves in the wrong direction as you can see on the photo. What should I do to lock it to the center of the duct? I have pinned it and locked and aligned to ref.planes.

Thank you,
Christian :-)

3. ## PSU formula

Here is the family I'm creating the formula for. :-)

4. Nothing? Any help?

5. You need to place dimensions from the ends to the center line, and then click the "EQ". This will keep the lengths equal and make sure the object stays centred as you change the length.

6. Brilliant! It works. Almost.
When I reduce the duct from 125 to 100 the PSU dosen't follow. It works fine from 200 to 160. What is wrong?

7. well... it all depends on how you have set up the family.

The 'best practice' for building parametric families is to start with the dimensions you want to change and in which direction they will change.
Then, model this with only ref planes and dimensions until you get it to work how you want (change the parameters regularly as you build it up, to see that it is working correctly)
Finally, Make your 3D geometry with extrusions etc and lock them to the ref planes so the size is controlled by the structure you already set up.

If you follow that kind of process it is much easier to see where something is wrong or to change how it works. If you begin with a 3D model and then try to make it parametric it can get messy quickly, until you get errors and you dont know what is causing them..

(Note; I dont always follow my own advice.. I do bad stuff like controlling dimensions of lines in sketches, putting stuff on the faces of other extrusions etc.. but start with the correct way first :P )