Components layout and connections - Page 1
Forum section: electronics / general

author: Kensou
author_rank: Newbie
timestamp: October 03, 2016, 09:42:43 am
content: Hello everybody, I'm new with Altium Designer Professional 2015 and I met the first issues about.I correctly imported my schematic from .ScheDoc file to a new .PcbDoc file, where I defined correctly a board.The footprints appeared in a suitable room, which is red colour, and they are connected by golden straight lines, as is described in the schematic.After that I tried to move the footprints to the board, for positioning at the correct areas. My problem is that, when I move the footprints, the golden straight lines change their connections, so that they are no more connected to the footprints as per schematic.This is a big problem since I want to define the footprints layout according to the schematic connections!Moreover, as the connections change when I move the footprints to the PCB, subsequent automatic routing would follow schematic connection or the PCB layout one?Thank you in advance for your help!!!

author: tszaboo
author_rank: Super Contributor
timestamp: October 03, 2016, 10:02:55 am
content: I'm almost sure this is a graphical (drawing) bug, or one of your settings are not correct. Try updating directx drivers. What system are you using? Altium always worked better with nvidia cards.Or maybe you are confusing DRC errors with connections. Press L (pcb editor) and check, if you are looking at the correct color. The "default color for new nets" is the connection to be routed.

author: Wilksey
author_rank: Super Contributor
timestamp: October 03, 2016, 10:10:09 am
content: Are you talking about the ratsnest?The ratsnest will just show you where the nearest connection point is, if you move a decoupling capacitor for example away from one chip to another, it will jump to those VCC and GND pins on the "wrong" chip.The autorouter is fine if you know how to use it, you can't just place components all over the shop and expect it to work miracles and know where you want it routed to 100%, you have to be careful with the design rules and the placement of components.The autorouter is probably intelligent enough to know that C1 is connected to U1 for example rather than U3 where it is placed, but don't rely on this, if C1 needs to be near U1, place it near U1 in the correct position. The ratsnest should update accordingly.

author: Kensou
author_rank: Newbie
timestamp: October 03, 2016, 11:47:18 am
content: Quote from: Wilksey on October 03, 2016, 10:10:09 am

author: Wilksey
author_rank: Super Contributor
timestamp: October 03, 2016, 03:57:09 pm
content: Yes, the ratsnest or airwires as they are also called are visual aids to help you visualise where the pad needs to be connected, if a capacitor for example has a GND pad and a resistor has a GND pad, there might be an air wire between them, but in fact you might want these to go to a ground plane, and there is a reason it's called a rats nest...They do not affect the final routing as far as I know, and you can auto route or manually route the traces afterwards.80% of designing a PCB is layout of components, the rest is common knowledge and routing skills and the ability to read layout guidelines in datasheets (something I've fallen foul on in the past from doing things in a hurry!)