Which SketchUp versions and platforms does RoadFlow run on?

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.

How is it licensed, and does the model stay usable without the extension?

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.

What are the limits I should know before buying?

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.

RoadFlowStop Fighting Roads That Won’t Fit the Terrain: Click the Route, and the Road, Terrain and Quantities Are Ready

Your presentation shows a road that sits on the land, not one floating above it. 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 · v1.16.0

Left: the job by hand. Right: the same job with the plugin.

RoadFlow

Every feature, at a glance

What the plugin does for you, drawn rather than listed.

A road with a real body

Carriageway, superelevation, shoulders, curbed sidewalks and median are set in the section, on a real body of 7 cm asphalt over 25 cm base.

Slopes that meet the ground

Cut and fill slopes run out at every station until they meet the terrain, with a concrete ditch or a stone retaining wall as the alternative.

The terrain tools come with it

Turn any flat face into grid terrain, shape it with the raise, lower and flatten brush, and on Apply the road is carved into it.

Roundabout, T, Y and X junctions

Junctions arrive with island, apron, dashed lines, signs and traffic lights; drag an arm and it becomes a side road that inherits every setting.

Street furniture on the real ground

Lamps, signs, guardrail, trees, vehicles and kilometre stones line the corridor at ground level, and any slot takes your own model from 10 formats.

Quantities with the long profile

The Road Report draws the long profile, and cut-fill volumes, asphalt and base, guardrail metres and accessory counts go out as a CSV that opens in Excel.

Workload test

99% less work with RoadFlow

By handHand-modelling one corridor and cutting it into the terrain

4 h

With RoadFlowClick the route, set the section, press Apply

2 min

99%

less time on this job

160×

faster

The time the same job takes by hand and with the plugin; the share and the speed-up are worked out from those two times.

The same job: your hours, or the plugin’s seconds?

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
One Line, a Whole Corridor
Click points on the terrain. One centerline becomes carriageway, shoulders, curb, superelevation, cut-fill slopes and ditches, while you stay focused on the route itself.
02
A Revision Is Not a Redraw
Right-click, Edit, drag the orange handles. Corridor, terrain fit, junctions and report rebuild in a single undo step, so a moved route never costs you the work behind it.
03
The Count Is Never on You
Every face is counted as it is built: areas, cut-fill volumes, asphalt and base, guardrail metres, accessory counts — one CSV, straight from the model.

How many evenings could this give you back?

road corridor per project

Projects per month6Hours on this task, per project4hours

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.

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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
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

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.