Mastering Rectangular Patterns

[Torymiddlebrooks]

Hello, 

I am just getting back into Fusion and I have a question about the rectangular pattern command.

I am making a laser cut box and will be using box joints for assembly. I would like to define a finger length and then pattern it down the length of the end to create the joint.

The problem I have is two fold but related

1) I don't know how to define the origin of the distance I need moved. I sketch a box, go to pattern it, select it and then the distance it moves and I don't know what that distance is measuring. 

 -69.5mm is the distance from what point to what point?

2) Is there a way to constrain the distance to the length of the piece? So that it will update the spacing if I change the height of the piece. I don't want to change the number of fingers, just their spacing. 

[jhackney1972]

Take a look at the Screencast and the model to see my setup.  First of all, you do not want to Pattern in the sketch environment, do it in the model environment.  The method I used DOES NOT calculate the notches so the beginning and the end are the same, this would take a little more match.  The Extends selection in the Pattern dialog takes the total length of edge and divides the number of notches into to it and calculates the space between each notch.  The notch width is constant can be changed as a parameter.

[Torymiddlebrooks]

That was very useful for a demo but I am still curious about my specific questions:

1) How does it pick the origin for the move? You and I both have it as the highest point in the Z, but is that always how it decides to start measuring? We have to minus the Notch_Width to get the distance instead of selecting a different origin.

2) Does this mean there is no way to constrain it to a dimension outside of parameters? Ideally I would like to be able to make the fingers colinear with the top and bottom and have the spacing between the fingers move when I increase and decrease the piece. For example, change Edge_Length to 400 and the top finger looks out of place.

[davebYYPCU]

This has been done as YouTube Tutorial, 

search for the channel - Hobbist Maker -

has a series of parametric finger jointed Box workflows.

Covers equal spaced and set finger counts,

uses Modelling Patterns, with Extrude Cut, and Combine Cut.

so no need for me to re invent the wheel.

Might help....

[g-andresen]

Hi,

For such patterns, I recommend always starting from the centre, developing the patterns symmetrically in both directions and using the "Spacing" option.
This way you always get the same length (finger or groove) at both ends.

günther

[jhackney1972 · Accepted solution]

I have attached a parametric model which allows you to set the end thickness of the first and last finger and then enter the width and count of the notches.  I will try and answer your questions.

1. I am parametrically calculating the available distance for all the interior notches and using Extent as the Distance Type Fusion 360 will center the requested number of notches that will fit within the available distance.  

2. The parametric model provided keeps the end spacing to the parameter specified when the overall length is changed.  You can vary any of the parameters with a gold star in front of it.  NOTE: The model will fail is the overall length is not large enough to contain the other paramaters.

[g-andresen · Accepted solution]

Hi,

in the screencast I show the method I talked about in my post 5.

günther