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Match up connection points between two PCBs on top of each other in Altium

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Junior Member level 3
Mar 21, 2002
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Hi guys, I hope somebody can help me with a problem that I have.
I have designed a PCB and want to expand it. I want to do that by making another PCB that sits on top of the 1st PCB like a sandwich. I then want to fit a four way female connector on one PCB, and male connector on the other one. The connector will carry the signal and supply pins.
The problem that I have is that I do not know how to super impose the two PCB drawings over each other so that I can see if the screw holes and connectors match up between the two drawings. Is there any way to do this?

Export a dxf or gerber file with relevant informations (e.g. drill or pad positions) from one design and import it to a doc layer in the other one.

A better way is to export a step model of one board, then create a component for the other board and assign it the step model (With appropriate height offset).

You can then create a design rule to allow the connectors (and only the connectors) to clash, at which point DRC will flag any components that have a collision in terms of height.

This is especially good when a board has parts on both sides, and the spacing is minimal as it neatly avoids those embarrassing moments when the boards come back from manufacture, and would fit apart from that cap....

Regards, Dan.

Why be so complex, the DXF method is the quickest and simplest way of getting things to line up initially.... Keep things simple is my motto, less errors then, you can also transfer height restriction areas etc. as well.
Also using the step method you have to presume...
The OP knows how to create a STEP file.
The software can create a step file directly.
Knows how to manipulate 3D assemblies and create constraints.
Has software to do this.
Knows how to read the data back into 2D PCB world.

Me initially I always use the simplest and most direct method, generally DXF, or in some rare cases IDF.

Sorry about the caps hit the caps lock instead of shift... but the above IS critical towards error free designs so I have left it.

Boards should always be checked for fit and collisions in 3D land as part of the intermediate and final checks, then you know the real assembly should go together... easy these days (and for the last 15 odd years) to also get 3D models made and try fitting the stuff together before expensive PCB fabrication and component assembly runs.......

I think both ways have their pros and cons. I have been using CAD tools without 3D support up to now, so I was restricted to dxf and similar anyway. But I see the points mentioned by Dan.

As the OP is apparently using Altium Designer, step import can be an option. I also confess to dislike receiving customer projects blown up by x Megabytes of step files.

I have and use Autodesk inventor so can play in 3D land to my hearts content, but I do recommend people keep things simple and don't complicate the design cycle, that's when things go wrong.
I would go as far as actually copying the old board and doing an ECO from the new schematic, then you know the holes are going to match... keep the old connector initially so you can line up the mating half, do that then get rid of the old connector job done, less errors.
I see more mistakes and problems when people get all giddy with their tools and use a more complicated method than required, when training on anything I always say keep it simple... we tend to overcomplicate many things in life when simple is best.:)
3D looks fancy and fun but it is just another step in the design cycle and unless I need to play in 3D land for form and fit, but often is overused and used where 2D would be a better option, but as I said it looks fancy (takes up computing power and fills your disk)....
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I did a little sidescan sonar, two boards, very dense, and the 3D interface was absolutely required to make the thing fit together (Let alone into the pressure housing), sometimes the pain is absolutely worth it, sometimes you don't need to bother, the trick is in correctly identifying each situation.

Altium actually has very good support for 3D and can do both the step import and export natively, I would not even have suggested going there were that not the case.

Disk is cheap, getting the mechanics right at the first try : Priceless!

Regards, Dan.

I use 3D for EVERY design I do to check the fit in the case, what I am on about is efficiency of transferring initial information between the PCB designer and the mechanical department, not always near each other or even in the same place.
To get the initial design information for a PCB design from the mechanical dept. a 1:1 direct DXF transfer is the best way to get some initial information such as board outline, connector positions, height restriction areas etc. into the PCB design. The main thing is to avoid reading drawings and transcribing dimension manually as this is where human error can creep in.
As to 3D and PCB layout it is nothing new, I have been using the IDF interface to 3D packages since at least 2000, with initially Autodesk AutoCAD 3d, then Mechanical desktop and finally Inventor and Solid Works, it is as I have said a necessary part of the design process with todays complex assemblies and space restrictions.
Altiums' 3D interface is interesting and far better implemented than most other packages, other packages still don't have a decent STEP output so the IDF interface will still have to be used to get the 3D information from the PCB package to a Mechanical system. Having a decent specked system is also a must when doing 3D stuff it is much more intensive in its use of resources and to have a flowing design throughput requires some computing power.
I have played with Zukens top end system that also allows 3D routing, for the majority of the design cycle though this is not necessary and can slow down the routing operations greatly, where it does have some benefits is on complex HDI boards where you have a sequence of blind and buried via's, but even here I would only use it in really complex areas. Efficiency and quality of the design cycle is what is critical and I use the most effective tools, interfaces etc. to achieve that at the requisite points along the product development to achieve this.
It always makes me chuckle when we are using 3D interfaces yet still use ancient and ******* Gerber to transfer data to the PCB manufacturers... even ODB++ is a better step, but even this is lagging when you compare how the ECAD-MCAD interfaces have developed over the same time frame.

I guess interfacing via DXF should be your choice.
However, interfacing via 3D STEP makes it possible as well, but I think it's gonna be a bit tricky and kind of an overshot, even if you will later need the correct board STEP model for the mechanics.
Interfacing via STEP seems to be time-consuming especially if you play with different parameters to correctly align the boards. It's not that quick even in DipTrace (PCB software that I use), which I think is quite intuitive and "low-on-clicks" software. Anyway, it's up to you.

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