Materials

Bridge Materials (a.k.a. Bridge Pieces; Materials) refer to components that make up a bridge.
There are eight official bridge material types, along with a ninth that is in the code, but was never implemented into any official release.

### List of Bridge Materials

Roads and Reinforced Roads are the only materials that cars collide with.

Roads, Reinforced Roads, Wood, Steel, and Hydraulics are rigid, meaning that they will offer support under both compression and tension.

Ropes and Cables are rigid only under tension, meaning that they will offer support under tension, but no support under compression.

Springs are not rigid, but they still provide some support depending on how much they are stretched or compressed. The more a spring is stretched or compressed, the more force it will apply to try and bring itself back to a "neutral" position, up until it breaks.

Bungee Ropes are not rigid, but they still provide some support depending only on how much they are stretched. The more a bungee rope is stretched, the more force it will apply to try and bring itself back to a "neutral" position, up until it breaks. However, it will offer no support under compression.

Joints are not a bridge material, per se, but is what bridge materials connect to.

To see how to use these, refer to Build Mode.

# Build Mode

Build Mode (a.k.a. Bridge Mode, Bridge Editor), refers to the interface in which the user is in when building and editing a bridge.

## Tools

> *Note that the toolbar can do different things depending on the mode, so make sure you are referring to Sandbox Mode or Simulation Mode for their respective toolbars.*
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> *There is also a distinguishment between "Sandbox" and "Sandbox Mode". "Sandbox" is the option to let you build your own levels, which, but "Sandbox Mode" refers to just the mode for editing a level.*
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> The ***Pause Menu*** Icon is three horizontal bars (≡). Clicking on it will give you an interface that will show you the following:
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* Resume - This will close the Pause Menu.
* Save Bridge / Save Layout - This will let you save your bridge (or level layout if you are in Sandbox).
* Load Bridge / Load Layout - This will let you load your bridge (or level layout if you are in Sandbox).
* Settings - This will bring you to the game's settings.
* Exit to Worlds Menu / Workshop Menu - This will bring you to the level selection screen.
* Exit To Main Menu - This will bring you to the original menu screen of the game.

The ***Level Info*** Icon is a little "i" within a circle. In a main campaign or workshop level, this will bring up the name of the level, description, and Level Phases.

The ***Tips Icon*** (only on PC) is a question mark (?). Clicking on it will show you hints.

The ***Sandbox Mode*** Icon(only on Sandbox) is a pail with a spade next to it. Clicking on it will bring you to the Sandbox Mode.

The ***Snap-to-Grid*** Icon is a 3x3 grid of squares, along with a magnet. Clicking on it will toggle the player's ability to snap to the grid.

* It is ON when the magnet symbol appears
* It is OFF when the magnet symbol does not appear.

The ***Stress Visibility*** Icon is a weight on a pedestal. Clicking on it will toggle the player's ability to see stress on bridge materials in Simulation Mode.

* It is ON when the weight symbol has a "T" in the middle of it.
* It is OFF when the weight symbol has has a slash (/) through the middle of it.
* You can enable Colo(u)r Blind Stress View in the Settings.

The ***Auto-Triangulate*** Icon is three circles connected with lines. Clicking on it will toggle the player's ability to place triangles.

* It is ON when the lines connecting the three circles are solid.
* It is OFF when the lines connecting the three circles are dashed.

The ***Auto-Draw*** Icon (only on mobile or by modding) is a large dashed circle with two smaller circles, with a line connecting the two smaller circles. Clicking on it will toggle the player's ability to automatically place pieces as they move the cursor (or move their finger across the screen on mobile.)

* It is ON when the line connecting the two smaller circles is solid.
* It is OFF when the line connecting the two smaller circles is dashed.

The ***Replay*** Icon (only on PC) is a film projector. After simulating a bridge, you can save a replay.

The ***Undo*** Icon is an anticlockwise arrow (⟲). It undos the last action you performed in the specific mode.

The ***Redo*** Icon is a clockwise arrow (⟳). It redos any action you had undone.

The ***Clear*** Icon is a trash can. It deletes the entire bridge.

The ***Cheat*** Icon is a red exclamation point (!). It is there simply to indicate to the player that the game detects there is something with the design that should not be allowed, and thus "Achievements, Leaderboards, and Unlocks are disabled." Hovering your cursor over it (only on PC) will give you a tooltip explaining why.

The ***Simulation Speed*** Icons are Guillemets / Double Angled Brackets (<< and >>). Clicking on them will change the speed of the simulation. The intervals are 20%, 50%, 100%, 200% and 300% Simulation speed.

The ***Start Simulation*** Button is a play symbol, indicated as a green triangle. Click on it will start the simulation.

## Trace Tool

The Trace Tool (a.k.a. Curve Tool; Straight Line Tool) is a semicircle with two dashed lines. It is a tool used to place bridge pieces along a curve or line between two points.

The ***Clear Tracer*** is an “X” icon. It removes the current path set by the trace tool.

The ***Locked Tangents*** is a lock icon. By toggling, it allows the player to move each tangent indepently of each other.

The ***Change Shape*** is a quarter-circle with points placed along it. It allows the player to change between a curve and a straight line.

The ***Fill*** is a paint bucket with a water drop falling out of it. It will fill the current path. The yellow slider next to it changes the maximum length of piece used to fill the path. The true length of pieces will be calculated to make each piece equal in length, but it will never exceed the set maximum.

## Build Border

There is a rectangular border around levels that prevents the user from building too far out in bridge mode.

The border extends from Y=-50 to Y=200 in the vertical direction, regardless of the position of the landmasses. However, the X values depend on the X position of the start and end terrain pieces. The left boundary is defined by the following:

X
B

=

X
L

X
R

2

±
175

{\displaystyle {X\_B = \frac{X\_L + X\_R}{2} \pm 175}}

XB is the X-coord for both sides of the bounding box

XL is the X-coord for the left terrain.

XR is the X-coord for the right terrain.

## Additional Technical Notes

* Bridges are saved as a `.slot` file .
* On PC, depending on when installed the game, the bridge files will be located in a different location.
	+ Before February 2021: `Documents\Dry Cactus\Poly Bridge 2\Saveslots`
	+ After February 2021: `AppData\LocalLow\Dry Cactus\Poly Bridge 2\Saveslots`
	+ You can determine where it is located by saving a replay (locally or shared to the online gallery), then copy the branch provided, and replacing "Replays" with "Saveslots".

## Trivia

* The grid doesn't actually extend infinitely. Instead, the texture is one huge square that starts at (-5000,-5000) and ends at (5000,5000), and does not move with the level.
* The build border was made with the intent to prevent people from creating falling roads, which is a Poly Bridge 1 budgeting strategy that places roads extremely high in the air, and drop them onto a vehicle to catapult them. This however, did not stop people from finding alternative strategies. *See: Glitch Exploits*.
* The Auto-draw feature exists on the PC version, but was never fully implemented. Because of this, it also has no ratelimiter, allowing you to place pieces at absurdly fast rates.
* A level can have materials not just darkened (indicating unavaliability), but also not appear altogether. The first 9 levels show examples of at least one material icon that is missing.
* The trace tool is a cubic bezier curve.
* The trace tool interface will display their names when hovered over with the mouse on Desktop, whereas on mobile, the names are displayed to the right of the icons.