5.8. Grading, Culverts and the 3D Object Viewer

5.8.1. Grading

Grading designs a graded pad — a building platform, parking lot, pond, or terrace — by projecting cut and fill slopes outward from a footprint at a design elevation until they daylight (meet) an existing-ground surface. The result is a graded terrain surface plus the earthwork cut/fill volumes.

A grading is a dynamic, self-contained object (AECC_GRADING): it owns and draws its own geometry (the graded TIN, the daylight line and any bench lines) — no separate polylines or surfaces clutter the drawing — and it recomputes automatically when you change its inputs. Grip-drag a footprint vertex and the graded surface follows live; edit a slope in the inspector and it recomputes at once.

5.8.1.1. The grading object

A grading binds three inputs and produces its outputs internally:

• Footprint — a closed (or open) polyline outlining the pad.

• Target surface — the existing-ground TIN (or DEM) the slopes daylight onto.

• Criteria — the design elevation, the cut/fill slopes, and benching.

From these it builds, and draws itself:

• the graded TIN (pad top + the sloped skirt out to daylight), styled by a surface style;

• the daylight line — the outer perimeter where the slopes meet ground;

• bench lines — the concentric terrace edges when benching is enabled;

• the cut, fill and net volumes against the target surface.

5.8.1.2. Creating a grading

1. Draw a closed polyline for the pad outline and have an existing-ground surface in the drawing.

2. Run GRADING (alias GRD), or Civil › Grading. The Grading dialog opens.

3. Fill in the criteria (below) and click Create / Build.

The Grading dialog groups the settings:

• Footprint — pick the pad polyline (all polylines in the drawing are listed; unnamed ones are auto-named so they can be referenced).

• Target surface — the existing-ground surface, listed by its civil name.

• Elevation — how the pad-top elevation is set:

  • Flat — a single design elevation for the whole pad.

  • Footprint vertex Z — the pad edge follows the polyline’s own per-vertex elevations (use a 3D polyline).

  • Drainage — the design elevation plus a constant cross-pad slope in a given direction (a drainage grade to a low edge).

• Cut / Fill — the outslope for each, entered as a slope (H:V ratio, e.g. 3 = 3:1) or a grade (%); toggle the Format to switch. Each perimeter point automatically uses the cut slope where the pad is below ground (excavation) and the fill slope where it is above (embankment).

• Benching — terraces on tall slopes, set separately for cut and fill:

  • Enable — turn benching on for that side.

  • Width — the horizontal width of each flat bench shelf (m).

  • Interval — the vertical rise between benches (m); a bench is inserted each time the slope has climbed/dropped this far.

  • Cross-slope (%) — an optional tilt across each shelf (a back-drain). A positive value tilts the shelf down toward the outer, slope-face edge so water collects at the toe of the upper batter; 0 = flat.

• Sample interval — how finely the perimeter is discretised (smaller = smoother daylight, more triangles).

• Max search distance — how far a slope may run before it is reported as ungraded (it never reaches ground within this distance).

Note

Cut vs fill sign. Cut and fill volumes are both reported as positive magnitudes; net = fill − cut (a negative net means net cut / export). A pad below existing ground yields cut; a pad above yields fill.

5.8.1.3. Dynamic editing and rebuild

A grading keeps itself up to date. With Auto rebuild on (the default):

• Grip-drag a footprint vertex → the grading recomputes and redraws live, every mouse-move.

• Move the whole footprint → it updates when you release.

• Edit a criterion (design elevation, a cut/fill ratio, benching, the surface style) in the Object Inspector → it recomputes immediately.

• Edit the target surface → the grading follows.

Turn Auto rebuild off (in the inspector) for very large pads; the grading then marks itself [stale] on an edit and you rebuild on demand with BUILDGRADING (alias BG) or the prospector Rebuild item.

5.8.1.4. Volume balance

Balance solves the pad’s design elevation so the earthwork hits a target net volume — most often 0, a balanced cut/fill site with no import or export.

Run GRADINGBALANCE (alias GRDB), or right-click the grading in the prospector and choose Balance…. Enter the target net volume (default 0) and a tolerance (default 1 m³). Because net volume rises monotonically with the pad elevation, the tool root-finds the elevation (bracket + bisection, re-running the grading at each trial), sets it, and rebuilds. It reports the solved elevation and achieved net, or that the target is not achievable for this pad within the search range (e.g. asking for more fill than the pad can physically produce).

Balance adjusts the design elevation, so it applies to Flat and Drainage pads; on a vertex-Z footprint (whose Z comes from the polyline) it reports that it needs a Flat or Drainage pad instead.

5.8.1.5. Extract, show/hide, lock

The grading’s graded surface is internal, but you can get a real one on demand:

• Extract Surface — GRADINGEXTRACT (alias GRDX) or the prospector Extract Surface item clones the graded TIN into a standalone AECC_SURFACE named <Grading>_Extracted, which you can section, contour, difference or feed to a corridor. It is a snapshot — re-extract to refresh.

• Show / Hide — the prospector Show/Hide item (or the Visible inspector property) hides the grading from the drawing; hidden gradings are not drawn and cannot be clicked.

• Lock / Unlock — the prospector Lock/Unlock item (or the Locked inspector property) prevents the grading from being selected or moved. A locked civil object is unlocked from the prospector node (not by clicking it on the canvas).

5.8.1.6. Selecting a grading

Click anywhere on the graded surface to select the grading and edit its values in the Object Inspector. A grading appears in the Civil Toolspace under a Gradings node, tagged [stale], [hidden] or [locked] as applicable; right-click it for Rebuild, Balance…, Extract Surface, Show/Hide, Lock/Unlock and Delete.

5.8.1.7. Grading commands

Command	Alias	Description
GRADING	GRD	Open the Grading dialog to create/build a grading from a footprint, target surface and criteria.
BUILDGRADING	BG	Rebuild a stale grading (when Auto rebuild is off).
GRADINGBALANCE	GRDB	Solve the design elevation for a target net cut/fill volume.
GRADINGEXTRACT	GRDX	Clone the graded surface into a standalone editable surface.

5.8.1.8. Limitations and notes

• Convex pads are fully supported. For a strongly concave / notched (e.g. L-shaped) footprint the graded TIN may bridge the notch — check the result on such shapes.

• Per-segment cut/fill overrides are supported by the engine and files but are not yet editable from the dialog (the global cut/fill applies to every side).

• Balance targets the design elevation (Flat/Drainage pads); vertex-Z pads are warned.

• Corner rounding is applied automatically (convex corners fan, concave corners trim), so the skirt closes cleanly at every vertex.

5.8.2. Culverts

Culvert creates a parametric box culvert — a reinforced-concrete drainage structure — as a dynamic 3D civil object (AECC_CULVERT) swept along a flow-line polyline. From a compact parameter set it builds the whole assembly: the box barrel (in segments), bottom and top slabs and haunches, the subbase and protection layers, inlet and outlet headwalls with splayed wing walls, footings and aprons, and an optional fall (drop) chamber — each as a solid part on its own layer, with a computed concrete volume.

Like a grading, a culvert is self-drawing and dynamic: it owns its part meshes and rebuilds whenever you edit its parameters or move the flow-line.

5.8.2.1. Creating a culvert

1. Draw the flow-line as a 2D or 3D polyline along the culvert axis (its vertices set the plan route; a 3D polyline also sets the invert levels). At least two vertices are required.

2. Run CULVERT (alias CULV), or Civil › Culverts › Culvert, and click the flow-line polyline when prompted (or pre-select it first).

3. The culvert is built with default box parameters and reported on the command line (“Culvert created: N parts, total volume = X m³”). Double-click it to open the editor and tune the design.

5.8.2.2. Editing — the Culvert editor

Double-click a culvert (or run CULVERTEDIT, alias CULVEDIT) to open the tabbed Culvert editor. Each tab draws a live cross- and long-section schematic that highlights the dimension you are editing:

• Box — the barrel: clear width B and height H, wall thickness T, top haunches, invert chamfer, bottom/top slab thickness, subbase and top-protection thickness, footing depth, and the segment length L1 (split the barrel into n equal pieces, or into fixed-length pieces).

• Left Wing / Right Wing — the inlet and outlet wing walls: splay angle, wing length, footing thickness and top slope for each wing panel.

• Fall Chamber — an optional drop structure at the inlet or outlet (None / Inlet / Outlet) with its inner size, wall thickness, floor drop and a stepped ditch profile.

• Materials — the material name assigned to each component group (box, subbase, protection, wings, fall chamber); used to group the quantities.

• Quantities — a live table of concrete volume per component and material.

Use Apply to rebuild the culvert without closing the dialog, or OK to apply and close. Load / Save store a parameter set as a .cvt template; Import reads a legacy GCulvert .txt parameter file.

You can also edit the box parameters and flow-line vertices, and read the total volume, directly in the Object Inspector when a culvert is selected.

5.8.2.3. Moving a culvert

The grips are the flow-line vertices. Grip-drag a vertex to move it in plan (its level is kept) and the culvert rebuilds along the new route.

5.8.2.4. Sections, quantities and report

• CULVERTSECTION (alias CULVSEC) cuts the culvert into a dimensioned 2D section — a cross-section at a station you pick along the flow-line, or a longitudinal section (run it with the LONG option). It draws the outlines, material hatches and dimensions at a point you pick.

• CULVERTQUANTITIES (alias CULVQTY) reports the concrete volumes — grouped by component and by material, with a grand total — and places a quantities table on the drawing.

• CULVERTREPORT (alias CULVRPT) writes a PDF report of the selected culvert: identity, a plan sketch with numbered stake-out points, cross and long sections, a volumes table, and an X/Y/Z coordinates table. Civil › Culverts › Culvert Report on the menu and ribbon.

5.8.2.5. Viewing a culvert in 3D

Select a culvert and open the 3D Object Viewer (OBJVIEW, below) to orbit the assembled solid, isolate individual parts and read part names and coordinates.

5.8.2.6. Culvert commands

Command	Alias	Description
CULVERT	CULV	Create a parametric box culvert from a picked flow-line polyline (built with default parameters; reports the part count and total volume).
CULVERTEDIT	CULVEDIT	Open the tabbed Culvert editor for a selected culvert (same as double-clicking it) to edit box, wing, fall-chamber and material parameters with a live schematic and quantities.
CULVERTSECTION	CULVSEC	Cut the culvert into a dimensioned 2D cross-section (or a longitudinal section with the LONG option) with outlines, material hatches and dimensions.
CULVERTQUANTITIES	CULVQTY	Report concrete volumes grouped by component and material and place a quantities table on the drawing.
CULVERTREPORT	CULVRPT	Write a PDF report of a selected culvert (identity, plan with numbered stake-out points, cross and long sections, volumes, X/Y/Z table).

5.8.2.7. Notes

• A culvert does not appear in the Civil Toolspace / Prospector. Reach it by clicking or double-clicking it on the drawing, or from the ribbon / menu / command line.

• The flow-line polyline drives the route — keep it in the drawing; the culvert references it.

• The angle and batter fields on the wing tabs are stored with the design but a few are reserved for a future solver revision; wing geometry currently follows the splay, length, footing and slope values.

5.8.3. 3D Object Viewer

The 3D Object Viewer is a separate, modeless window that isolates the objects you have selected and shows them in true 3D — orbit, shade, hide individual objects and pick to inspect. It is read-only: it never changes the drawing. It is ideal for checking a surface, a grading pad or a culvert (or several together) in three dimensions without leaving your 2D layout.

5.8.3.1. Opening the viewer

1. Select one or more objects that have 3D geometry (surfaces, gradings, culverts, 3D polylines).

2. Open the viewer by any of:

   • OBJVIEW (alias OBJECTVIEWER);

   • View ribbon → 3D pane → Obj Viewer;

   • right-click the canvas → Object Viewer….

The selected objects are isolated into the viewer. Objects with no 3D geometry are skipped (a note appears in the status bar).

5.8.3.2. Navigating

• Left-drag — pan.

• Right-drag — orbit (rotate).

• Middle-drag — pan.

• Wheel — zoom.

• Preset views — a dropdown of Top / Bottom / Front / Back / Left / Right and the four isometric corners (SW / SE / NE / NW).

• Zoom Extents — frame everything.

• Ortho / Persp — toggle parallel vs perspective projection.

5.8.3.3. Display modes

A dropdown selects how solids are drawn: Wireframe, Hidden Line, Flat, Gouraud, Shaded + Edges (default) and X-ray. Surfaces are rendered double-sided and smooth-shaded, so a TIN never drops triangles when you rotate it.

5.8.3.4. Object list — show / hide / isolate

The left panel lists one row per object (a multi-part culvert is a single row):

• Checkbox — show or hide that object.

• Double-click a row — isolate it (hide the others) and refit the view.

• Show All — show every object again.

Below the list, a summary panel reports the object, triangle and vertex counts and the XYZ extents.

5.8.3.5. Inspecting

Hover the cursor over the geometry and the status bar reads out the point under the cursor:

• for a TIN / graded surface triangle: XYZ, elevation, slope % and ratio, aspect (compass bearing) and triangle area;

• for a culvert part: the part name and XYZ.

5.8.3.6. Colours

Surface triangles are coloured by the surface’s elevation-band style (the low-to-high gradient set in the Surface Style Editor); gradings and culverts use their entity colour. Lighting shades the result.

5.8.3.7. Live update

While the viewer is open it tracks the objects you loaded and updates automatically when you edit them in model space — grip-drag a surface point or a grading footprint, edit a culvert parameter — and the 3D view follows within a moment, keeping your camera angle and any hidden/shown state. A Live toggle (on by default) turns this off for a frozen view. The viewer follows the objects by handle, so they no longer need to stay selected.

Reload re-syncs to the current model-space selection if you have one, otherwise it refreshes the objects already shown.

5.8.3.8. Object Viewer commands

Command	Alias	Description
OBJVIEW	OBJECTVIEWER	Open the 3D Object Viewer on the current selection: orbit, shade, show/hide and isolate objects, pick to inspect, with live update while you edit in model space. Read-only.