mairomaster , 07-01-2016, 05:18 AM
It is still not very clear to me. Do you want to know:
1. Which size of component you should use - for example if you need to use 0201 capacitors or 0402 capacitors.
2. Why for a particular size of component, lets say 0402, you have very different footprints.
I am assuming it is 2. A simple rule to follow is if you have a resistor, use a resistor footprint, if you have a capacitor use a capacitor footprint, etc. Based on my experience and a lot of research, I recommend using standard IPC footprints for the chip components (resistors, capacitors, inductors). Such footprints you can generate yourself with the Altium IPC footprint wizard. Also you can find some on the web, but they are not always very reliable. If you have access to the Altium vault, you can get such from there as well.