Looking at a trouser pattern shape problem

So, Hello! I am back after a very lengthy hiatus - its funny how we lose interest or motivation over time for some of the things we do. Other platforms pop up and it satisfies something different or us, and for me I think I needed a break and IG seemed useful, but it has issues too and I guess I found that my thoughts are less "Insta" so to speak.

but anyway......recently on Instagram....and her accompanying blog-

Handmade PHD was recently trying to dissect a pattern for trousers that were not working for her and I have a few thoughts as to whats going on there. She has been looking at various patterns and how they perform by virtually trying them on 3D avatars. 

So, instead of burdening her comment section,  I figure I could post some of my thoughts here instead.  

This is the digital pattern shape she is working with. She has drawn in grain lines from the centre point of the hem and knee on both pieces. That seems to be reasonable assumption on the front but not on the back as the perpendicular angle of the knee and crotch line don't make sense. 

I think there was a problem with the way the basic pattern has been developed, either at the block stage or during manipulations of the basic block.

Here is an example of a flat trouser draft from Metric Pattern Cutting for Menswear as an example - this would be the draft I would imagine would be used for this style of trouser. On the left they show a block developed with a straight side seam (which could be placed on the fold and cut as a one piece pattern) or, for a slightly better fit, a flat two piece trouser block.

Even in a flat block, the front and back of the pattern must directly relate to each other in the block development drafting stage.

From the basic block, one may then make modifications, like adding pleats to the front, without distorting the relationship between the front and back

Unfortunately the back pattern piece she has looks like it was from the straight side seam block and the front from the two piece. They just don't work together.

On the two piece block, you should be able to superimpose the front on top of the back, match the hem level, and centre the front piece over the back piece. The backs, which are drafted wider that the fronts at both the hem and knee, should have an equal amount showing beyond the fronts at the knee and the hem on both inseam and outseam. The centre leg/grain line should be right on top of each other.

Here is a little that exploration I did.

1. if side seams were straight, the centre front goes off grain and front hem at inseam drops 

2. the front is overlaid on the back, centered at the hem but the knee is not centred 

3. if the hems are on the same plane with the hip hip area touching, there is a big offset in the lower leg.

 

I also wonder why the back waist line has virtually no rise to it. You can see that the CB waist point is only marginally higher than the side seam at the waist. 

hmmmmmmm, I wonder if their back waist measure was too small, and to increase it,  they slashed and spread it? no, I tried that in a paper model and it didn't produce that kind of shape. 

I'm stumped there.....

But... I can imagine if the back waistline does not rise much above the horizontal construction line for the waist, then the centre back seam length must be made to intersect with the back inseam length somewhere out there in space. I can see how someone might make that make sense somehow.

I mean, there are patterns that don't have any rise in the back waist, which may look something something like this- of course that straight CF/CB line must be long enough to accommodate the full girth, so the crotch point will be quite a bit lower than a trouser with shaped CF/CB seam.   

 

There are some other issues that bear examining, like inseam length and side seam shape, but that will have to be discussed in the next post.

Do you have issues with the patterns you make up?