A copy & paste tool for Cities: Skylines II - select props, trees, decals, painted surfaces and (since 1.1.0) whole buildings; copy them and stamp them anywhere with preserved layout, rotation, and height.
Save-game safe. Copaste only ever writes the game's own (vanilla) components - it stores no custom data in your save file. A city touched by Copaste loads identically with or without the mod, and unsubscribing leaves nothing behind. Undo history and session data live in memory only.
Copaste started as a personal tool: we wanted a group copy/paste and blueprint workflow for prop detailing that no existing tool offered, so we built one for our own city. It grew feature by feature - undo, blueprints, a proper UI - until it felt useful enough to share, so here it is.
It was built by studying the source code of the excellent open-source mods credited below. Their MIT and Apache-2.0 licenses explicitly permit exactly this kind of learning and reuse - that openness is what makes the CS2 modding scene great, and this mod is published under the same spirit (MIT). Copaste is not a replacement for Move It or ctrlC; it is a different, detailing-focused workflow that can happily live alongside them.
The short version. The complete reference with every detail is in docs/features.md.
- Click & marquee selection - click individual items, or drag a camera-aligned box on the ground to select whole groups at once (live highlight while dragging). Works on props, decals, trees, painted surfaces and buildings
- Selection filters - five toggle chips in the panel (Props, Trees, Decals, Surfaces, Buildings) control what selection picks up; right-click a chip to solo it (right-click again to bring all back). Buildings are off by default
- Buildings (new in 1.1.0) - move, rotate, raise/lower, copy, paste, blueprint and delete whole buildings with everything they own: driveways, pavements, purchased upgrades and attached props move as one piece. A Relocate mode walks the selected building to a new spot with live road snapping; Road snap also auto-faces pasted buildings to the nearest road. Buildings under construction can be deleted (with undo) but not moved
- Building elements toggle - lets selection reach elements owned by buildings, each following its filter chip: props, trees and decals (delete or rearrange them - deleted ones stay deleted for the whole session even when the building is moved or relocated) and lot surfaces (select and delete with undo - deleting a decoration surface also removes whatever it keeps spawning on the lot). With the toggle off, nothing building-owned can be selected, not even by click
- Painted surfaces - select by click or marquee, move with the selection, copy/paste, delete with undo, and save into blueprints
- Copy & paste with preview - the copied group follows your mouse as a ghost preview; click to place, as many times as you like
- Layout preserved - relative positions, rotations, and heights above terrain are kept exactly as in the original group
- Group rotation - hold right mouse button and drag to rotate a selection (or the paste preview) around its center
- Move - drag a selected prop to move the whole selection, layout and heights preserved
- Delete - remove the whole selection with one key. Combined with marquee + type filter it makes bulk cleanup trivial: box-select an area, press T on a tree to keep only that tree type, hit Delete - a whole overgrown forest gone in three clicks (Ctrl+Z brings it back, growth stages preserved)
- Paste onto roads & paths - the group lifts to the surface you point at
- Original colors kept on paste - pasted props keep the source prop's color variation and any custom color picked in the game's Customization tab; a blue bench stays blue. An Original/Random toggle in the panel restores the old randomized behavior. The ghost preview shows the real colors too
- Align tools - Line turns a messy selection into a tidy row (straight line, equal gaps, all props rotated the same way); To prop does the same anchored to a reference prop you click; Circle arranges the selection evenly on a circle. Afterwards,
[and](or the panel stepper) resize the layout live - the gap can also be typed in exact meters - Per-prop touch-ups - Alt+drag moves a single prop out of the selection; Alt+mouse wheel spins every selected prop around its own axis (great after a Line align)
- Ctrl+click picking - selects props partially buried in other objects or buildings that a normal click can never reach; repeated Ctrl+clicks on the same spot cycle through everything piled up there
- Anarchy-style pasting - placement errors (overlapping items etc.) are ignored while pasting (toggleable in options); pasted props are protected from being hidden by the game when the Anarchy mod is installed
- Undo & Redo - Ctrl+Z reverts the last action (move, rotate, align, height change, delete, paste, relocate), up to 32 steps back; Ctrl+Y re-applies it. Deleted trees come back with their original growth stage and colors; deleted buildings are rebuilt complete with pavement and driveways (fresh residents move in - simulation state is not copied)
- Blueprints - save the copied group to disk and reuse it in any city or save; managed from the in-game panel (paged list, inline rename); colors are stored too, older blueprint files still load
- Type filter ("Same") - press T to toggle a filter taken from the hovered/selected prop: marquee then only picks that exact type (works for trees too)
- Nudge & snap - fine-position the selection with Ctrl+arrows, drop it back to terrain with End
- Toolbar button + panel - a top-left toolbar button toggles the tool; the panel (draggable, remembers its position) shows counters, the selected prop's name, a per-prop list for selections up to 50 (hover rings the prop in the world, click isolates it), align controls and your blueprints
- Rebindable hotkeys - all shortcuts can be changed in Options → Copaste → Key bindings
- English, German, French and Serbian options localization
The quick table. Every command with a full explanation, panel controls included, is in docs/commands.md.
| Action | Input |
|---|---|
| Toggle tool | Ctrl+Shift+C or the toolbar button |
| Select a prop | Left click (white circle on hover, blue when selected) |
| Pick a buried/overlapped prop | Ctrl + left click - repeat on the same spot to cycle through stacked props (Shift+Ctrl adds to selection) |
| Add/remove from selection | Shift + left click |
| Marquee selection | Left click on empty ground + drag (Shift adds to selection) |
| Move selection | Left click on a prop + drag - the whole selection follows the mouse |
| Move a single prop | Alt + left click on a prop + drag - only that prop moves |
| Clear selection | Click on empty ground |
| Copy selection | Ctrl+C |
| Paste (preview follows mouse) | Ctrl+V, then left click to place - repeat to stamp multiple copies |
| Rotate selection / paste preview | Hold right mouse button + drag (hold Alt to snap to 45°) |
| Spin each prop around its own axis | Alt + mouse wheel (15° per notch) |
| Align: tidy row | Line panel button - straight line, equal gaps, uniform rotation |
| Align: row through a reference prop | To prop panel button, then click the reference prop (RMB cancels) |
| Align: circle | Circle panel button (3+ props) |
| Adjust align gap live | [ and ] while an align button glows, or the panel stepper (type a number + Enter for exact meters) |
| Raise / lower selection or paste preview | Page Up / Page Down (hold for continuous) |
| Delete selection | Delete |
| Undo last action | Ctrl+Z (works in paste mode too - removes the last stamp) |
| Redo | Ctrl+Y |
| Relocate a building | Tab or the Relocate panel button (single building selected, Buildings filter on) - building follows the mouse with road snap; click places, Tab/right-click cancels |
| Type filter ("Same") | T - toggles a filter taken from the hovered/selected prop: while active, marquee only picks that prop type; clicking any prop switches the filter to its type; press again to clear |
| Match height | Home - arms height picking: the next prop you click sets the height for the whole selection |
| Nudge selection | Ctrl + arrow keys (camera-relative, hold for continuous) |
| Snap selection to ground | End (in paste mode: resets the height offset) |
| Save / load blueprints | Panel buttons - Save stores the selection/clipboard; clicking a name loads it and immediately starts pasting; ✎ renames, ✕ deletes |
| Back / clear / exit tool | Quick right click |
Blueprints are stored as text files in ...\Colossal Order\Cities Skylines II\ModsData\Copaste\Blueprints\ - rename or delete them freely. Props from missing mods are skipped on load.
Buildings are selectable since 1.1.0 behind the Buildings filter chip (off by default - with it off the tool behaves exactly like the prop-only versions). Vehicles and citizens are never selectable. By default selection only reaches free-standing objects; the Building elements toggle extends it to things owned by buildings - props, trees, decals and lot surfaces. Individual lot decorations that the game re-generates randomly on every lot update (clotheslines and similar) stay excluded on purpose - deleting them one by one could not stick without writing mod data into save files, which Copaste never does. Deleting the decoration surface they spawn from does stick, and that path is supported.
To keep the game responsive, selection is capped at 1000 props and selection circles are drawn for at most 400 at a time (everything selected is still highlighted). The tool guards its own update loop, so an unexpected error disables the current action instead of crashing the game.
Found a problem? Open a bug report: the form asks for the few things needed to fix it, including the Copaste.log file (the form shows where it lives). Ideas go to a feature request, questions to the forum thread. Every report gets read.
Detailed docs for every part of the code live in docs/ -
architecture, the tool system, the paste pipeline and color preservation, align
tools, undo, the blueprint file format, the cohtml UI (including Gameface
engine gotchas), settings/input, and build/deploy.
main- matches the latest published release on Paradox Mods; releases are taggedvX.Y.Zdev- active development; merged intomainat release time after in-game testing
The project uses the official CS2 modding toolchain (install it via the game's launcher first - it sets up the CSII_TOOLPATH environment and Mod.props/Mod.targets):
$env:DOTNET_ROLL_FORWARD = 'LatestMajor' # ModPostProcessor targets the .NET 6 runtime
dotnet build Copaste.csproj -c ReleaseThe build runs the game's IL post-processor, produces Burst native libraries for Windows/Linux/macOS, and auto-deploys everything (DLL + UI files) to the game's local Mods\Copaste folder.
Two quirks worth knowing if you hack on this:
EntityManager.CreateEntity(archetype)does not compile under the toolchain'snet48profile (missing span types - the official project template has the same issue); use theCreateEntity(archetype, count, allocator)overload instead.- The hand-written UI module (
ui/Copaste.mjs) uses the game's runtime globals (window.React,window["cs2/api"]) instead of imports - ES imports silently break UI modules.
AI-assisted development: the code was written with heavy use of AI tools (Claude Fable), directed, reviewed and hand-tested in-game by the author through many iterations. Bug reports are read and fixed by a human.
This mod stands on the shoulders of the CS2 modding community - it was written from scratch, but the patterns and APIs were learned from open-source mods whose licenses (MIT, Apache-2.0) explicitly welcome that. Sincere thanks to:
- yenyang - the selection, highlighting, and raycasting patterns were learned from the MIT-licensed sources of Better Bulldozer, Anarchy, Tree Controller, and Move It; Anarchy's
PreventOverridecomponent is integrated at runtime when present - algernon - the object placement approach (the game's definition pipeline) was learned from the Apache-2.0 sources of Line Tool
- Bruceyboy24804 - Node Controller's UI module served as the reference for how mod UI integrates with the game's interface
- Colossal Order & Paradox - for Cities: Skylines II and the official modding documentation
- The Cities: Skylines Modding community for keeping their mods open source - none of this would have been possible otherwise
A very special thank-you to Biffa (Biffa Plays Indie Games) and ConflictNerd - simply for being the author's favorite Cities: Skylines YouTubers and the reason this game never gets boring. Keep the traffic flowing! 🍵
MIT - see LICENSE.