Multiple board outlines don't render nicely in 3D


#1

I’m doing something oddball here, so I’m not going to foam at the mouth if there’s no way to make it work easily.

I’m running 4.02. I have a project that I’m breaking up into three boards, with jumpers in between. Rather than having three schematics (which, granted, is seeming smarter and smarter all the time), I have one schematic and three boards. When I send stuff off to the fab house I just make three copies of the PCB, delete two boards out of each one, generate gerbers, and off it goes.

When I try to render all three boards in 3D, the leftmost board renders correctly, but the other two boards are missing outline and what I think you guys call the board “body”.

Is there an easy fix for this, or should I render with the same copy-and-delete procedure that I’m using to make gerbers?

TIA.


#2

KiCad currently renders a “board body” for only one of the closed outlines of Edge.Cuts.
You might see the expected 3D preview by adding little tabs betwen your three boards, that you will delete before sending it for frabrication. That way the 3D viewer would see only one big board.


#3

KiCad runs on an ancient assumption that there can only be one board outline and anything else is a cutout. Unfortunately there has also been a lot of resistance to making changes that would make multiple solid bodies possible, so I don’t imagine this problem being fixed for many years.


#4

Thank you both.

@cbernardo: well, I knew I was doing something hinky.


#5

I have a board, divided into 3 with 2 V cuts on the edge cut layer. There is an overall continuous outline edge cut
3d viewer complains, but does display it correctly


#6

@davidsrsb
You might actually not see the outline you did draw all around, but a ‘replacement’ by KiCAD that then just takes a ‘bounding box’ approach and makes a board from that.

As has been said by the others… draw a closed outline with tabs between your boards and KiCAD won’t have a problem.
My projects involve me ordering 100x100 mm boards, so I put every board I need into one project and create mouse-bite break-away tabs (1 mm milling for separation) on that 100x100 mm panel to separate them later (mostly after reflowing them all together).


#7

You can also draw an external big edge and put a scoring inside to break the boards … that wouldn’t add costs in most pcb fabricators…
The scoring has to be uploaded as mechanical drawing…
Just check your fab house if they accept it and how they need the info and respect their spacing for the scoring…
Maurice


#8

Hi all,

Sorry to necro the thread, but @caer , @Joan_Sparky ;

What are these “tabs” you speak of? Are these “breakaway tabs”? Could anyone just draw a quick outline and place these “tabs” and post a screenshot, so I can see what it looks like? Or if not, any links to a screenshot where this is visible?

Thanks!


#9

Officially they might be known as “perforated breakaway tabs”, more commonly known as “mouse bites”. If you google for “pcb mouse bites” you can find many examples.


#10

Thanks @bobc - that explains it… But does KiCad’s Pcbnew hace a special entry for these tabs, or is it just a matter of drawing lines on a specific layer; and if so which one?


#11

search this forum for mouse bites.
Here the top result


#12

The tab is basically an outline on Edge Cuts and some drill hits. Unfortunately use of edge cuts layer in footprints is not officially supported, so often lines are marked on silk screen or other layer and an arc must be drawn over them on edge cuts after the footprint is placed on board.

I don’t recall where I got this lib*, but here is an example :

However, for the purposes of the 3d display (original post), then any sliver connecting the boards will render them correctly. I thought I had an example but I can’t find it.


FAQ Index Thread
#13

Added these last two references to the FAQ.