Electronic – How to merge polygons into a single pad

Making the footprint is generally one of the fastest of all the things you need to do. There are Wizards in Altium that help you make IPC-compliant footprints quickly, and you can set the text height, silk screen line widths and so on to conform to your specific requirements and so your boards have a consistent appearance and set of manufacturing requirements.

Populating the data base with all the things that should be there (vendors, part numbers, alternates, prices, and so on) takes longer. Making a 3D body, if you need to, can take a lot longer depending on your proficiency with 3D parametric modelling software and whether you want to do a good job, a spectacularly good job, or something more slapdash. Here's a rendering of an LED body I did some time ago- the actual die dimensions and position is shown but I didn't bother with the bond wire. The typical library parts often have a crude 3D block or nothing at all.

You only make the part once and you can re-use it thereafter. It's a big hassle to add parts to inventory for the rest of the company, so maybe it will make you think twice about reuse.

Anyway, if you're at the beginner stage (we've all been there) and you just want to get going, use an 0805 resistor and it will be sub-optimal but usable (ignoring the 3D features and such like). You can edit it to show the polarity and save it in a library of your own. You can also download someone else's library that's been done more-or-less properly and (hopefully) learn from that and create your own as you gain experience. IIRC, the 0805 and other Imperial standard footprints may use the metric equivalent numbers (2012 for 0805) as part of their names.

I once made a diode with a four-pin anode, all of which I wanted to connect together. You could connect all of the anode pins separately, but I would recommend giving them different pin names (i.e. 87a, 87b, 87c) and treating them as separate pins on the PCB layout. However, on the schematic, lay the three pins one on top of the other so it looks like just one pin. Altium will see a wire connected to the "one" visible pin as connected to all three pins, and will tell you to route all of their corresponding pads together. You will need to go into the pin editor on the schematic, though, and make sure you change the pin names and which pads they connect to. That's probably the most elegant solution.