3D Printing: SLA Vs. FDM
3D printing with an SLA printer is additive. It works from the ground up to make some. The SLA has a high resolution, but is slower then an FDM printer. SLA is also very expensive to use, as the materials is very pricey. These are important thing to think about when designing.
Subtractive Manufacturing involves taking something and taking away material to make something. When thinking about trying to design something, you have to keep in mind the drill bits and how big they are, because it won't have a precise cut.
When laser cutting, when designing you have to keep in mind the type of material you want to cut and how a laser would effect it. The material will also all be flat when cutting, so when putting things together, it would be like a puzzle piece. You would have to design joints and try forsee how it would be connected.