The latest version of the guide can be found here:
https://docs.google.com/document/d/1uZ5sXU3nPH4K9zaHWSiWZ554j8wqEAX7g4Xe6bT0In8/pub

There have been cases where you need to restart Steam after first installing Fortify for it to work.
Check this out if you’re still experiencing issues:

https://support.steampowered.com/kb_article.php?ref=6218-USFX-5568

Some controls and shortcuts can be customized under the input tab.
You can lower the graphics settings here if using an older computer or building a ridiculously large base.

'Save As' only saves files in the main saves folder.
Subfolders can be added but the files need to be moved manually. Reopen the menu to refresh the file list.
The Save button will save to wherever the file was loaded from.



Clipboard Export allows you to copy the save data to your clipboard.
Some web services have a character limit which could result in incomplete save data if pasting into a message.

That's why https://pastebin.com/ is a good choice and you can get automatic links with this button:



The generated link is copied to your clipboard for sharing.
The Fortify subreddit has lots of posted designs that are shared this way.
Submit your own unique designs for feedback. Warning: You may get downvoted for no good reason.

Importing from Pastebin
Copy the “RAW Paste Data” (Ctrl+A to select all) and then use Clipboard Import.

Tab switches between build and place mode.
It’s a good idea to copy your saves folder for backup purposes.

• Keyboard Shortcuts
  esc - open or close main menu
  F12 - take a screenshot
  
  
• Camera Controls
  Can be customized in initial settings for AZERTY keyboards.
  Invert Y-Axis is available under Options.
  W/S - forward and back.
  A/D - pan left and right.
  Hold right click to rotate the camera.
  Hold shift to speed up all camera movement.
  Space/left Ctrl - move the camera up and down.
  
  
  
  Interior Camera Mode - Slows the camera down and prevents it from going through walls.
  
  
• Merge Saves
  
  
  
  Copy contents from a file into the current scene.
  Left click to place the contents, it can be rotated while moving around.
  Importing a huge base or a 3D terrain save with foundations at different heights might not give you the best results.
  The merged parts stay selected after placement so you can just delete if you’re not happy with it.
  
  
• Deleting Parts
  Highlight part and press R / backspace / delete. This can be used after selecting multiple parts in Edit mode.
  
  
  
  Restores last deleted part or parts.
  
  
• Hide Floors
  Hidden floor parts still have active colliders to prevent overlapping from below.
  Page up and down are the shortcuts to adjust the hide floor level.
  Click the tab below the arrows to jump to the first floor.
  
  <---
  
  
• Building Tiers
  
  
  
  Toggle the tier used for new parts while in Build mode or click to change the current selection in Edit Mode.
  
  
• Allow Overlap
  
  
  
  Parts can intersect freely.
  Cupboards can overlap each other.
  Certain parts can now break Rust rules and be placed on the ground or on floors/foundations.
  
  
• Add Codes
  
  
  
  Select doors while in Edit mode to use this. Multiple doors/hatches can be set at once.
  Mousing over the door will show the code.

Foundations

• Hold down left click and move the mouse up and down to adjust the height.
  
• After placing the first foundation hold down left click (next to the first) to to make placement continuous.

Wall parts can replace other walls without deleting (change a wall to a window).
Press 1-7 part shortcuts repeatedly to cycle through groups, like floor and floor tri.
Swapping similar parts can also be done with mouse3.
Doors and roofs will flip sides while placing with Q / E.
Stairs and Hatches can be rotated after placing with Q / E.


Strong/Weak Side

All wall parts have a strong and weak side, use Q / E to flip while selected.
While placing press Q / E to change if the strong or weak is facing the camera.


Weak side_____Strong side

Items can be rotated while placing with Q / E / scroll wheel. Hold alt to get finer rotation.
Click placed cupboards to see radius.

• MouseOver Selection
  Default selection mode, left click to add to selection or hold mouse over parts while holding left click to add, hold alt to remove from selection.
  
  
• Rectangle Selection
  
  
  
  Press M or mouse 4 to toggle.
  Hold alt or ctrl - remove or add to the selection.
  Disables up/down movement.
  
  
• Level Selection Tools
  
  
  
  Goes through every level with a selected part and adds or removes from the current selection.
  Going left to right: selects everything, only floors, only wall parts, and any part types that were in the original selection.
  
  
• Add Level
  
  
  
  Select foundations or floors first. The top option outlines and the other honeycombs the selection with walls.
  Floors will be placed above if the bottom “include floors” toggle is enabled (on by default).
  
  
• Copy Level
  
  
  
  Will copy any selected building part (includes frame parts) one level up.
  
  
• Copy Structure
  
  
  
  Selection must contain a foundation. Rotate with Q / E / scroll wheel.
  
  
• Align
  
  
  
  First select the parts you want to align/move (must contain a foundation).
  Click on the ground next to the target edge you want the parts aligned with.
  This uses the colliders used in foundation placement which is shown below.
  Lastly choose the edge of the selection you want aligned to the target.
  Here’s the tool in action: https://imgur.com/E89CiMP
  
  
  
  This tool doesn’t prevent overlapping where the two structures come together.

Will only show the count for visible floors.
The other tier toggles show the cost if every building part is changed to that tier.
Click the panel to update the count.

Saves a temporary copy of your scene that will load back when exiting this mode.
It’s still a good idea to save before switching to this mode, especially with large bases.
All deployables are removed in this mode, this might be improved in the future.
There was an update to the stability code (January 2017) that makes it much more accurate to Rust.

Destruction Mode




The cannon ball knocks out parts in the hit radius.
Mouse over parts while using C4 to see the health.

This option saves and loads .json files that are configured to work with the Copy-Paste oxide plugin.
Get the plugin and more info here: http://oxidemod.org/plugins/copy-paste.716/
Try it out with your own server: http://www.rustafied.com/how-to-host-your-own-rust-server/

• Pasting
  Once your server is setup add the json files to the copypaste folder:
  server > "your server name" > oxide > data > copypaste > example_base.json
  You might need to create the copypaste folder.
  Then type in chat: /paste example_base
  
  
• Filenames with spaces need to be in quotes: /paste "example base"
  Undo placement: /undo
  Adjust the height (1 is default): /paste example_base height 2
  
  
• Copying
  /copy example_base
  The building part you are directly looking at will be at zero elevation in the save (so look at a foundation).
  The file will end up in the location mentioned above.
  
  

Multiplayer is only 2 player for now and uses steamworks P2P networking.
Host and let your friend know you’re ready.
If joining it will timeout after 15 seconds if no host connection is found.
The host’s scene is sent to the joiner at the start. Save before joining.

• resetting the scene effects both users, same goes for loading a save
  
• saving only saves to your computer
  
• leaving a session will not reset anything for the other user
  
• stability mode is disabled during a session
  
• hide floors is synced

If repeated connection attempts fail it might have to do with this: Required Ports for Steamworks P2P