Help with a rectangle pattern spacing equation

[SlowEvo]

.f3d attached.

I have a series of squares(I labeled them blocks in parameters), spaced evenly with a 1mm gap between each. For every 2 squares wide, underneath will have one rectangle spanning 2 squares. I figured out an equation that spaces the rectangles correctly when the model is 6 squares wide. If I change a parameter to say 8 squares wide it the rectangles don't space out properly. Same if I reduce it to 4 squares wide.

When it works properly:

 

After changing to 8 squares wide:

 

I'm using the rectangle pattern tool(in the sketch, this better suits my need in this case).

In the rectangle pattern tool:

Quantity= countWide/2

Distance= blockWidth * ( countWide / 2 + 1 ) + ( spacingWidth * ( countWide / 2 + 1 ) )

Those parameters:

countWide=6

blockWidth=25mm

spacingWidth=1mm

 

All parameters:

 

I'm really, really bad at math and honestly am surprised I even figured out as much as I did.

Could someone please help me figure out the correct equation so it will update properly?

Also I know the amount of rectangles wide will have to be an even number.

[jhackney1972 · Accepted solution]

I did not want to add to your Parameter table so I added my extra equations to the Sketch Rectangular Pattern command.  I also edited your existing Parameter called "rectangularWidth".  Model attached.

[SlowEvo]

Wow thanks so much for that! One thing I dont understand is how its getting the information to add more rectangles if I add more blocks.

Edit:

I see it must have something to do with you changing Distribution to Spacing while I had it at Extent. I've never played with this option, I'll have to learn more about it and it's use cases.

[SlowEvo]

Included original message in edit above.

[jhackney1972]

As my screen capture indicates, I have created a Rectangular Pattern on the rectangular sketch.  You can add the equations to the Parameter table is you wish but since you have only a sketch, I added the required equations to the rectangular pattern dialog box.  The quantity is using one of your existing parameters.

[SlowEvo]

Thanks so much again!