I feel that this is a little lengthy, especially for concepts, but here are my ideas for these buildings:

Let's say that we get these buildings with an alternate PDA instead of a wrench. (I know of at least three on the Workshop.)

Let's start with the shield generator:

Costing 100 metal to build, the generator projects a spherical bubble around a given area, let's say, a radius of 100 Hammer Units (HU). This is equal to 6.25 feet. It can even project beneath itself. The bubble can be penetrated by players only; projectiles and hitscan weapons won't work on the bubble. (The Pyro's flamethrower, however, can penetrate the bubble, as can all melee weapons.)

There's just one catch, though. As I've said, projectiles and hitscan weapons can't penetrate the bubble, but they CAN wear it down. (The flamethrower and melee weapons can't.) Depending on how much damage is inflicted, the shield loses a set amount of strength. (Minicrits and full crits wear it down more.) However, the generator passively repairs the shield as it gets damaged. (Think about getting damaged yourself while being healed.) If it sustains, let's say, 750 damage, the bubble breaks down entirely. It would be 5 seconds before it can generate a new one. (The generator itself, on the other hand, has the same amount of health as a dispenser.)

The generator, like any other building, can also be upgraded. Each upgrade level increases the bubble radius by 50 HU (3.125 ft.) to a maximum of 200 HU (12.5 ft.) at level 3. Additionally, level 2 generators take on a role meant to be played by the Repair Node, by repairing any damaged buildings within the bubble. It will not, however, dispense health for the Engineer's teammates. Level 3 generators also resupply ammunition to nearby sentries within the bubble. This, to some degree, would allow an Engineer to leave his nest safely.

Now let's talk about the traps:

Once upon a time, during the game's beta when mercenaries carried grenades, the Engineer had bear-trap grenades that slowed the enemy down. This building essentially brings that back.

Traps are a bit simpler compared to the generator. Two at a time can be built, just like teleporters. Unlike teleporters, however, they are not linked to one another, so upgrading a trap to level 3 before building another will not automatically upgrade the next trap. For Spies, traps must also be sapped separately.

When an enemy player walks over the trap, the trap triggers, instantly causing 50 damage, bleeding for 10 seconds, and slowdown by 40% for 5 seconds. Traps reset automatically after 8 seconds.

Traps cost 50 metal each to build, and can also be upgraded. Each upgrade level increases the initial damage by 25 points, bleed time by 5 seconds, and reduces reset time by 2 seconds. Their health is the same as that of a teleporter.

On a related note, it would be nice to get miniaturized models of these buildings, should the Engineer choose to equip the Gunslinger. If the developer chooses to make these, I have stats for them as well:

Instead of a bubble, the mini-generator projects a wall about 90 HU (5.625 ft.) tall and 160 HU (10 ft.) wide, 100 HU (6.25 ft.) in front of it. Like its full-sized counterpart, it can stop projectiles and hitscan weapons, but the passive recharge is much quicker than the full-sized version. (Think getting healed by the Quick-Fix versus the stock Medigun.) As a trade-off, the shield can withstand less damage before breaking, perhaps only 550 damage. But the wall can regenerate in 3 seconds. (And no, Mexico will not pay for it.)

The traps would be of a much simpler design, perhaps just a blade attached to a mechanical arm swinging at the victim's ankle. These traps would deal only 25 damage, and bleeding for 5 seconds, but the slowdown is greater-- 80% for 5 seconds. They reset after 2 seconds.

So, over to you Steam. What do you think of these stats? Are there numbers you want to change, mechanics you want to add or cut? Please, feel free to add to the discussion. Thank you for reading.

--Mysafir