Make a Fleece Jacket
Sometimes making stuff is just about clothes that fit or that do what you want and not what manufacturers want. At other times it's about saving weight. For example my SilNylon rain coat is based on a commercial coat pattern that I've bought and then I've changed the design to add another 18" of length, lose the pockets and lose the full-length zip.
If you are making your own ultra-light or specialist clothing there is no need to sweat the design. There are lots of basic patterns available online or in your local haberdashery. These basic patterns are designed to be the starting point or the inspiration for doing your own thing. If you want to keep things simple then you buy a pattern that covers your clothes size and then make a garment based on the instructions in the pattern. This is a good way to start.
Maybe a fleece jacket pattern could in fact be made in Pertex for a close-fitting wind-shirt. Maybe those cargo pants could be made in Cordura? The trick is to recognize that a sewing pattern is a general direction, an idea. A sewing pattern will suggest fabrics that the designers had in mind but there is nothing to stop you using completely different fabrics.

This garment is a good example of how patterns can be used as a starting point rather than as a destination. I've even sewn my own label into it (I used to make stuff to order).
Anyway the original design pattern was McCall's M5991. The pattern offers several variations of a fleece garment - A jacket with collar or hood , a full-zip or half-zip hoodie, a full or half-zip body warmer with a collar or hood. The variations come about by how the various panels are assembled and whether you sew on a hood or a collar. I chose this pattern from half a dozen or more that were available from McCall's and Simplicity and others. I just went for a pattern that was close to what I wanted for a fleece coat.
However I could look at this pattern and think "I could make a nice micro-fleece body warmer" or "if I don't do the pockets I could make a nice pertex wind-shirt from it". I see the pattern as a toolkit of things that save me time.
In this case I've taken their jacket pattern and I've changed it.
1. I've added about 4" to the length so that it's a full-length jacket. I've used a long double-ended zip that I had lying around and then made the jacket around that by making the jacket longer and then making the hems line up with the zip. If I had been less accurate I could cheat around the collar and gain or lose an inch in length.
2. I've added an elasticated adjustable waistband to it - like you find on most fleeces.
3. I've made it with a baggy fit rather than a slim fit - basically I've made it a size larger than it needs to be and then taken it in.
4. I've fitted a baffle behind the zip.
What I might still do is elasticate the arms. I haven't' done this and I'm still in two minds about it.
Now for once this jacket is not as good in performance terms as one I could buy. This is because I cannot easily find wind-proof fleece such as Gore WindStopeer. It is however just what I want for a casual jacket. It was also a good experiment in making a jacket - something I've not done before.
Drifting away from the design pattern may seem scary but there's nothing to worry about it. What you can do is simply look at a garment you own that has been commercially made and ask "how did they make that"? Take a look at the seams and see where the fabric has been stitched or folded and then wonder if it can be done easier or lighter or faster.
For example the zip baffle above is just a bit of fleece folded over and top-stitched about 1cm from the fold. The other side of it by the zip has just been overlocked. A commercial jacket may use two pieces of fabric sewn together. By using one I've saved some time and effort.
