> Because it can eliminate having to manually transpose dimensions > and therefore, a source of error.
Let keep it in perspective: PCB design is governed by IPC , mechanical widgets are govenened by ASTM, ASE, ( not sure about all the acronyms) but the whole point is IPC says it must be viewed one way. Not your way or ASTM way etc. > Sure. That makes perfect sense once it is complete. Does it define > "primary side" ? Is that the side with the most bits, the one the > through-hole parts are on, the one that matches all the mechanical > drawings of the complete product or something else ? Yes IPC T50 defines the primary side as the side with the most components sec 22.184 > > I've never seen a drawing of a chair with the legs at the top, but I > am sure it spends some time like that at the upholsterer. Why > should it be any different when I am laying out a PCB ? > I cant speak for the chair it is governed by "tag removal" laws which I do not have documentioan on. I guess the chair can be rotate without contradicting IPC standards since IPC does not apply to the chair > In fact, I have a job at the moment where it would be a really useful > tool. There are two boards that plug together component side to > component side. If such a tool existed, I could place components > on both sides of a single outline so that I could check for > interferences as I go. I could also put the connectors on top of > each other so that I know they will match up. Once I am happy, I > could select everything on the bottom layer and flip them with a > copy of the outline. Now I have two boards as they will be > manufactured on a panel, with the components on the top, no > transposition errors and I still have the ability to keep in sync with > the schematic. > You can flip x or y now and it flips correctly so why does anyone what to flip so it contrary to design standards? I dint get your point, but I have seen boards backwards when these standards were ignored. The problem is that mech engineers and designer dont know how to view a board. Mike Reagan EDSI Frederick * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://email@example.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *