Can you reference the last element of a rectangular pattern

[MrGubbins]

I'm making a battery holder. The battery model is basically a box, which I repeat using the rectangular pattern. After I execute the pattern, I create a sketch at the bottom that I want to extrude up so that it "hugs" all the batteries. The problem is that no matter how I reference the last object in the pattern, when I change the number of items in the pattern via a parameter, the bottom sketch never updates to cover all the newly added elements in the pattern.

As you can see in the screenshot, I increased the number of items in the pattern, but the bottom sketch remained the same even though I'd projected the last item in the pattern and reference that while creating the offset box.

Can this be achieved in Fusion 360? Referencing the "last" item on a pattern, that is.

 

[g-andresen]

Hi,

What is your goal?
Do you want to create a box for a variable number of batteries?

Please share the file.

File > export > save as f3d on local device > attach to next post

günther

[davebYYPCU]

Your sketch does not “know” how many batteries are present.

Dimension the sketch, with a formula based on spacing and count.

Might help.....

[MrGubbins]

Hi, thanks for the prompt reply!

> What is your goal? Do you want to create a box for a variable number of batteries?

Yes, my goal is exactly that. I don't have a file unfortunately. I only just started and what you see in the screenshot I posted is as far as I got before I stopped and came to the forums. Since I couldn't figure referencing off a pattern I was wondering if that was even possible and will approach my design based on that constraint.

If I have do this for a fixed number of batteries, that's OK too. I just want to know before I start designing.

[MrGubbins]

> Dimension the sketch, with a formula based on spacing and count.

OK, makes sense. I thought that since Fusion had already computed that formula for me while using the rectangular pattern tool, I could reference from the pattern object itself. The downside of doing this is that if I go back and change how the pattern is calculated (say, the spacing formula) I need to do this again in my sketch. No big deal, just was hoping to avoid this.

[jhackney1972 · Accepted solution]

I have attached a model demonstrating the use of Parameters to accomplish what you desire.  I only added parameters to determine box length but you can add parameters to change the width as well.  The video will describe operation.