Parameterized box expands into the wrong direction

[cwienands]

I am working on my first "complex" model in Fusion 360 for a 3d-printed cell phone holder (coming from TinkerCAD). I am making slow but sure progress. I have parameterized pretty much everything there is to parameterize. But now when I tested that everything would expand and contract correctly, I found this was not the case.

Specifically, I started with a box with one corner at the origin. When I modify width and length of the box, that said corner stays on 0/0/0 and the "non-zero" edges scale. However, after adding a number of fillets, cuts using sketches and such, when I change one the parameter that affects the length of the box, the right side (positive x) stays fixed and the left side moves from 0 to negative x. When I use "Edit feature" on the original box in the timeline and modify the dimensions, the left side stays fixed, as expected. Any idea what is causing this, and how to fix it?

[davebYYPCU · Accepted solution]

Yep, Pic 1, timeline icon number 1, is not a sketch

I started with a box with one corner at the origin.

Box does not work with parameters, for your intent.

Might help....

[cwienands]

Thank very much you for your input. I've experimented a bit more: I added another primitive box and played around with  parameterized length in both the "Edit Feature" window as well as modifying a parameter value in the "Change Parameters" window. Just to make sure that there isn't something in the subsequent steps that modify the box that would force it to expand to the left (-x). The behavior of the band-new box is the same: EF window changes affect the right side, parameter changes affect the left side. Doesn't make any sense!

So a primitive box can be parameterized but now I am wondering what exactly "...for your intent" means? Primitives must play some role in Fusion, otherwise they wouldn't be there. But if they can't be properly parameterized, when would it be safe to use them?

In the meantime, I tried to replace that box with a sketch. Haven't found an easy way to do that yet 😞

[TheCADWhisperer]

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@cwienands wrote:

Primitives must play some role in Fusion, otherwise they wouldn't be there. 

In the meantime, I tried to replace that box with a sketch. Haven't found an easy way to do that yet 😞

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@cwienands 

A new baby has to start out at some limited level of functionality.

As it gets older it starts to develop more sophisticated functionality.

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[cwienands]

Sure, here is the model. The parameter in question is CellWidth.

[TheCADWhisperer · Accepted solution]

See Attached...

I always use symmetry about the Origin when possible and practical and the BORN Technique.

[cwienands]

Symmetry about the origin makes perfect sense. BORN technique seems to require some deeper study. Thanks for the pointer. 

In the meantime I read in numerous posts that primitives are pretty much only meant for quick sketching and that  people essentially avoid them like the plague for anything else. 

Time to start over…