PCB Card Routing Backward Engineering
In view of layout orientation from PCB Card Routing Backward Engineering, if we view the board from soldering side, the layout orientation of the components must keep the same with schematic diagram, and the layout orientation is better keep the same way as the schematic diagram orientation from pcb card backward engineering.
Since in the process of production, there are a lot of parameters testing will be proceed on the soldering side, so if designed in this way can provide a lot of convenience for the inspection, debugging and maintainence after pcb card backward engineering.
2nd, use as few curve on the tracks layout as possible, and the width of the tracks should not changed abruptly, in case the tracks need to bend for more than 90 degree it is better to keep it in a clear situation.
3rd, there is no crossing will be allowed in the circuit pattern from pcb card backward engineering, as for those tracks with possibility to cross, designer can use drill, or detour which can help to detour one of the lead to other one which could have the chance to cross.
That means the lead should go through the resistors, capacitors and triode space, in order to simplify the design process when backward engineering pcb card, or circle around the tracks which could probably cross the tracks, in some special cases the layout design could be very complicate, so track overpass interconnection is also allowed for design simplification, to tackle the track cross issue.
And if use the single layer board, all of the inserted components are all on the top layer, and surface mount components on the bottom side, so in the process of pcb card backward engineering, inserted DIP components can cross the surface mount components but need to avoid the soldering pad overlapping.