Building Blocks - Line Diagrams

Over the years of doing Nearly Insane, I've had a few questions asking me how I figure out what to cut.  I chose not to provide dimensions for the blocks I was doing since that would mean you didn't need to buy the book and I figure that violates the copy right.  So, instead I'm doing a tutorial on how I figure it out.

I've started out with a 6" finished block (that means 6 1/2" unfinished).  Sorry, no fancy PDF download. When the line drawings are thick like you see here, I take my measurements from the centre of the line.  Though, as long as your consistent, it won't matter.  Centre is just easiest for me since I don't have to pay attention to the orientation of the block then.

The Centre of this block (picture below) is a 3" finished (3 1/2" unfinished) square made up of 9 squares that are each 1" finished.

Element A - The 4 1" finished white squares.  For a plain square or rectangle what you need to do is take the finished measurements and add 1/2".  So, since these ones finish at 1", I cut each square 1 1/2" x 1 1/2".

Element B - The 4 1" finished half-square triangles.  These are blue and white in the picture below.  To make half-square triangles, you take the finished measurement of the base (in this case 1") and add 1" to the measurement.  So, for these ones I cut 2 squares white and 2 squares blue, each measuring 2" square.  Then I made them following the tutorial for half-square triangles.

Element C - The centre 1" finished quarter-square triangle.  To make quarter square triangles, you take the finished measurement of the hypotenuse (in this case 1") and add 1 1/2" to the measurement.  So, for this one I cut a blue and a yellow square, each measuring 2 1/2".  Then I cut each square diagonally to make 4 triangles.  Got rid of 2 blue and 2 yellow triangles and used the rest to make up the centre.

Next I moved onto the outside.

Elements H & I - These are the flying geese that finish at 1 1/2" by 3".  For these I used the fast flying geese method.  The base, larger square (swirly pink & yellow fabric in the picture below) made by taking the finished measurement of the base (in this case 3") and adding 1 1/4".  So for this block I cut one square of the swirly fabric 4 1/4" square.  The smaller outer triangles are made by cutting 4 squares.  For these squares you take the finished measurement of the height (in this case 1 1/2") and add 7/8".  So for this block I made 4 squares that are 2 3/8" by 2 3/8"

Just for demonstration purposes I used both methods to make the square-in-a-square blocks.  Normally I wouldn't do that, I just did it to show you how I work out the measurements for each type.

Elements F & G - For the upper two corners I used the squares method of making the square-in-a-square blocks.  For the centre square - Element F (blue in the picture below), you take the finished measurement of the whole square and add 1/2".  So, since this block finishes at 1 1/2" by 1 1/2", I cut a blue 2" square.  The smaller outer triangles - Element G (yellow in the picture below) are also cut as squares, 4 for each element.  To do this, you take the finished measurement of the triangle base ('B' in the square-in-a-square tutorial) and add 1/2".  So, for this one I cut 4 yellow squares, each 1 1/4" by 1 1/4".

Elements D & E - For the lower two corners I used the triangles method of making the square-in-a-square blocks.  For the centre square - Element D (blue in the picture below), you take the finished measurement of the centre square and add 1/2".  So, since Element D finishes at 1 1/8", I cut a blue square 1 5/8" by 1 5/8".  The smaller outer triangles - Element E (yellow in the picture below) are triangles.  To do this you take the finished measurement of the triangle base ('B' in the square-in-a-square tutorial) and add 1".  So, for this block I cut two yellow squares, each 1 3/4" by 1 3/4" and then cut each square in half diagonally to make 4 triangles.

And that is how you figure out what you need to cut from fabric when you're faced with a line diagram for a pattern.  The first couple of times I did this, I was double checking and second guessing everything.  After I made a few blocks, I started recognizing these elements more and more and can now do most of them in my head (greatly speeding up the cutting process).

And, since I couldn't resist, here is the finished block!

I hope this tutorial helps everyone faced with line diagrams (Like you are with Nearly Insane, or Dear Jane, or ....).  If you have any questions or anything is confusing, please let me know.