Overview
Design Roads takes the roads you have already drawn and designs them into the terrain. For every PVX road that has a centerline (internal, boundary and service roads), it calculates a longitudinal profile with vertical curves, cross sections with cut and fill slopes and an optional ditch, and the earthwork quantities. It draws profile sheets, cross-section bands, curve and quantity tables, and slope hachures on the plan. The road plan and each road’s width are used exactly as drawn and are never moved. Where a road breaks a rule, for example a grade steeper than the maximum, the problem is marked on the plan instead of being fixed.
PVX.AI has three road tools. Choose by what you already know about the roads:
- Editing Road Centerlines: you decide where the roads go. Draw or convert them, reshape the centerlines and run Rebuild Roads. This sets the plan only.
- Design Roads (this guide): the plan is fixed and you need the vertical design and quantities for those roads: profiles, sections, cut and fill, and grade checks.
- Generating Roads During Grading: you do not have a route yet. PVX.AI routes new roads from the site entrances you pick and grades them together with the PV area in one run.
The order matters: edit the centerlines first, then run Design Roads. If you run Grading after Design Roads, the graded terrain replaces the road corridors and the road design becomes out of date.
Prerequisites
Terrain in the drawing, and roads drawn with a centerline: manual roads made with Draw Road or Convert to Road, boundary roads and corridor service roads. Roads without a centerline are skipped and named in a warning on the command line: closed outlines, imported roads and the road platforms made by Generate Roads.
Step-by-Step Guide
1. Finish the road plan
Put every road where it should be and run Rebuild Roads if you edited a centerline. Design Roads reads the centerlines as they are in the drawing, so any plan change after the design means running it again.
2. Open Design Roads
Go to Civil sub-tab > Earthworks > Design Roads. There is no selection step: every road with a centerline is designed. If the drawing has no terrain, the window says so and the run button stays disabled.
3. Set the longitudinal profile
- Max grade (%): the steepest slope allowed along a road (default 8).
- Min grade for drainage (%): the flattest slope allowed, so water runs off the road surface (default 0.5).
- Crest curve K and Sag curve K: the length of vertical curve per percent of grade change at crests and dips (defaults 3 and 4). Higher values give longer, gentler curves.
4. Set the cross section
- Cut slope (H:V) and Fill slope (H:V): horizontal to vertical ratio of the side slopes (defaults 1.0 and 1.5). Use the values from your geotechnical report.
- Cut-side ditch and Ditch depth: a drainage ditch on the side where the road is in cut (on by default, 0.4 m). Untick it to design without a ditch.
- Crossfall (%): the sideways slope of the road surface (default 2).
The road width is not set here: each road keeps its own width. An invalid value, such as a minimum grade above the maximum, is named in red under the fields and the run is blocked until you correct it.
5. Decide whether to apply to terrain
Apply to terrain is off by default. Off, the run only draws the design and its quantities; the terrain is not changed. On, the designed road corridors are written into the current terrain, the slope colours of the changed faces are updated, and each PV area the corridors touch gets a slope comparison table. Racks inside the regraded corridors are not moved: the command line gives their count, and you can run Adapt Objects or Adapt Terrain to Pile for them. Ctrl+Z restores the terrain.
6. Run and read the results
Click Design Roads in the window. The calculation runs in the PVX.AI cloud. On the plan you get, for each road:
- the 3D design centerline and the daylight lines where the side slopes meet the ground;
- slope hachures: lines drawn from the top of each cut or fill slope, long and short alternating, so you can see on the plan where the road is in cut and where it is in fill;
- grade problems on PVXAI_Roads_Violations: a marker, the offending stretch and a label such as RO-3: grade 0.21% below min (0+120.00 – 0+180.00).
The report drawings are placed beside the site on layers that are turned off after the run, so they do not crowd the plan. Turn them on in the Layer Manager to read them: PVXAI_Roads_Profile (a profile sheet per road with chainage, existing ground, design elevation, cut and fill, grades and vertical curves), PVXAI_Roads_Sections (cross-section bands), PVXAI_Roads_DesignTables (horizontal curve and quantity tables) and PVXAI_Roads_Labels.
7. Keep the design current
Running Grading after Design Roads overwrites the road corridors in the terrain. PVX.AI then warns on the command line that the road design (profiles, sections, quantities) is out of date. Reset Terrain also marks it out of date. Nothing re-runs by itself: run Design Roads again on the new terrain.
Tips & Recommendations
- Run once with Apply to terrain off to check grades and quantities, adjust the plan or the rules, and apply to terrain only for the final run.
- If the terrain already holds corridors from an earlier applied run, the next run warns that its cut and fill are measured from that earlier design. Reset or re-grade the terrain first when you need the full quantities from the original ground.
- A grade violation means the drawn route cannot meet your rules on that ground. Move the road, add a bend to lengthen the climb, or accept a steeper maximum grade if your standard allows it.
- A Generate Roads run (from the Grading window) replaces the Design Roads output. Use one approach per site.
- Generate Terrain Profile and Generate Cross-Section now ask for a slope label interval (10 m by default) and write the ground grade between ticks, for example +4.2%. Answer None to draw no slope labels.