FREE Urban Design
CityFill
Fill the empty city around your building in a few clicks.
- 154 presets
- 3 placement modes
- SketchUp 2021-2026
SketchUp 2021–2026v2.0.0
RoadFlow
No more hand-stitched road sections
Draw a centerline on any terrain and RoadFlow builds the whole corridor — superelevation, cut/fill slopes, ditches, junctions and a CSV quantity report.
- 408 tests green
- 13-35x faster builds
- 7 road presets
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SketchUp 2021 · SketchUp 2022 · SketchUp 2023 · SketchUp 2024 · SketchUp 2025 · SketchUp 2026 · Windows (PowerShell install/build scripts) · v1.16.0
The same job, twice.
Drag me
With the plugin
2 min
Click the route, set the section, press Apply
By hand
4 h…
Hand-modelling one corridor and cutting it into the terrain
Drag me
- 01
Draw Once.
Click points on the terrain. One centerline becomes carriageway, shoulders, curb, superelevation, cut-fill slopes and ditches.
- 02
Change Anytime.
Right-click, Edit, drag the orange handles. Corridor, terrain fit, junctions and report rebuild in a single undo step.
- 03
Measure Automatically.
Every face is counted as it is built: areas, cut-fill volumes, asphalt and base, guardrail metres, accessory counts — one CSV.
How much time could this save you?
road corridor per project
Estimate based on a typical workflow. Your mileage will vary - usually upward.
Saved every month
0,0hours
Saved every year
0 hours
0 work days
You just found 245 hours of your life.
Not on sale yet
The technical bit
For the people who read the manual first.
- Works with
- SketchUp 2021 · SketchUp 2022 · SketchUp 2023 · SketchUp 2024 · SketchUp 2025 · SketchUp 2026 · Windows (PowerShell install/build scripts)
- Version
- v1.16.0
- Interface languages
- tr
- Centerline is a Catmull-Rom spline with stationing: profile smoothing from 0 (hug the terrain) to 100 (engineered profile), maximum longitudinal grade clipping, and a horizontal corner fillet radius, 12 m by default and 60 m on the motorway preset.
- Fully parametric cross-section - carriageway, crown and superelevation, shoulders, sidewalk with curb, central median - sitting on a real pavement body: 7 cm asphalt wearing course over 25 cm granular base.
- Cut/fill daylighting solves every slope surface by iterative bisection against the terrain mesh, with a concrete ditch (continuous or cut-side only) or a stone retaining wall as an alternative to slopes.
- Terrain Studio is built in: grid terrain from any flat face at a chosen cell size (250k node safety cap, 50 x 50 m at 1 m by default), a raise/lower/flatten brush with cosine falloff, and terrain carve-and-fit with edge imprinting on Apply so slope bands survive coarse grids.
- Junctions cover roundabout (ring, apron, raised island, dashed lines, signs), T, Y and auto-detected X with fillet radii, stop lines and traffic lights; road, markings, guardrail and accessories are trimmed out of the junction area, and dragging a T/Y arm generates a real side road that inherits every parent setting. A crosswalk tool lays zebra stripes and pedestrian signs on the road plane.
- Accessories run along the corridor at real ground elevation - street lamps, signs, steel guardrail or wooden fence, trees, lane-centred vehicles in traffic direction, pedestrians, kilometre stones with 3D chainage text - and each slot accepts your own model from file (.skp, .glb, .gltf, .dae, .3ds, .stl, .kmz, .usdz, .obj, .fbx) with automatic base-centering and real-world scaling.
- Road Report window gives a longitudinal profile graph (cut red, fill blue) plus a quantity table: lengths, platform/shoulder/sidewalk/median/slope/wall areas, cut-fill volumes by average end-area, asphalt and base volumes, max grade, minimum curve radius, marking and guardrail lengths, accessory counts - exported as UTF-8 CSV that opens straight in Excel.
- Design check list scores green/yellow/red on maximum longitudinal grade, minimum curve radius against a design speed of 30-110 km/h, stations where the slope hits the width limit, terrain grid coarseness, and stations that fall outside the terrain boundary.
- Every zone lands on its own SketchUp tag - 15 of them, from platform and shoulder to ditch, retaining wall, markings, guardrail and centerline - so any part can be hidden per view; textures and accessory components are generated procedurally and seamlessly with UV aligned to the road axis, so there is no binary asset dependency and no CDN in the panel.
- Everything stays editable: settings live in an AttributeDictionary, right-click Edit reopens the panel with saved values, Edit Route drags orange handles and rebuilds, Road From Line turns any existing edge or curve into a route; the panel previews at coarse resolution and the final build lands as a single undo step in 0.02-0.11 s (13-35x faster since v1.14.0), covered by 408 automated tests that run without SketchUp.
Still being built
Shipped, and what is next.
Shipped
- v1.16.0 - your own model in any accessory slot, from 10 file formats, auto base-centered and scaled to real size; wooden fence added
- v1.14.0 - road generation down from 1.4-3.9 s to 0.02-0.11 s (13-35x), smoke suite from 335 s to 4.5 s, and the missing slopes and ditches fixed
- Junction set finished: roundabout, T, Y, auto-detected X and crosswalk, with dragged arms generating side roads that inherit every parent setting
- Terrain Studio: grid terrain from a face, sculpting brush with cosine falloff, carve-and-fit with edge imprinting on Apply
- Road Report: longitudinal profile graph, full quantity table, design check list at 30-110 km/h, UTF-8 CSV export
Next
- Full English interface - the STRINGS table is already built for it, only the dictionary is missing
- Bridges, viaducts and grade-separated interchanges, deferred from v1 to V2
- macOS packaging - install and build scripts are PowerShell-only today
Before you ask
SketchUp 2021 through 2026, Ruby 2.7+ with HtmlDialog, installed as a normal .rbz. Windows is the tested platform - the install and build scripts are PowerShell. One version note: importing your own .glb/.gltf models needs SketchUp 2024 or newer, while .skp, .dae, .3ds, .stl, .kmz, .obj and .fbx work on every supported release.
One purchase, one seat: you get the .rbz and install it into your own Plugins folder. It runs fully offline - no account, no CDN in the panel, no per-project fee, and every texture and component is generated procedurally inside the extension. What it draws is plain native SketchUp geometry, grouped and tagged, so the model opens and prints normally on a machine that does not have RoadFlow; you only lose the right-click re-edit.
Three honest ones. Bridges, viaducts and grade-separated interchanges are V2 work - v1.16 covers at-grade roundabout, T, Y and X junctions plus crosswalks. The panel is Turkish only for now; an English dictionary is next on the list. And slope accuracy follows your terrain: a coarse grid gives coarse daylighting, which is exactly why the design check list flags grid coarseness and stations outside the terrain boundary. If you have roads built with v1.9-v1.13, one re-Apply restores their slopes and ditches.
Worth reading
The Best SketchUp Plugins, Sorted by the Job You Hate
Twenty SketchUp tools sorted by the job you are sick of doing — walls, openings, floors, stairs, facades, roads, take-offs. Real numbers, and a plain word on what is still unfinished.
Read →
How SketchUp Plugins Actually Make You Faster
A wall moves 40 cm at six in the evening. What that costs is the real measure of a workflow. Here is where the minutes go, job by job, and which bottleneck to fix first.
Read →
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