Draws a cross section through the plan from the Civil 3D surface the drawing was exported with. Click the two ends of the cut inside a viewport that shows a surface, then click the side the section looks toward: the arrows at the cut's ends point that way, and left and right in the section follow the arrows, not the order you clicked. With a two-point line selected when you pick the tool, that line is the cut and the tool goes straight to the side. A window then asks what the section should show, and a last click places it, lower-left corner first.
The section draws at the viewport's scale across, and at that scale times the vertical exaggeration up; any exaggeration other than 1 is written under the section. Its slabs and walls draw their materials' tiles at that same plan scale (a 12 in paver is 0.05 in long in a section cut from a 1" = 20' viewport), the sheet around them being unscaled.
The ground line is the surface cut exactly, triangle by triangle, so a curb or a wall built into the surface shows as the step it is. Under it the ground mass runs down to a datum.
The window lists the layers in the viewport with the role each starts with, read from its material and its name: Pavement hangs a slab under the ground line wherever the cut crosses a closed area on that layer, in the layer's material; Building stands a box on the ground where the cut crosses a footprint; Wall rises from the lower ground to the higher.
The Material column offers a choice for Pavement and Wall rows; a Building row draws as Building, and a row with no role has no material.
Every depth, height and wall thickness is yours to type, in the drawing's units: a layer with a role and no value is left out and named in the status bar, never drawn at a guess. A Building or Wall row whose layer has a Height (the height its shadows are cast from) starts from that height, and the box's tooltip says so; type over it to use another, and the row then keeps what you typed.
A row you have not changed in the window follows its layer from one section to the next: give the layer a material or a Height later and the row picks it up the next time the window opens. A row whose role, material, depth or thickness you set stays as you set it.
The depth of view says how far behind the cut, square to it, plants and objects are shown; it starts at the distance to the viewport's edge, and the band it covers shows on the drawing until you place the section.
Plants and objects stand at their own ground, drawn with their side views, farther ones behind nearer ones and the ground in front of them all, so a tree on lower ground behind the cut is hidden at the foot by the profile, as a real section shows it. They stand at true height however the ground is exaggerated unless you tick Stretch symbols.
Trees says how they are drawn: Rendered stands their side-view pictures, treated by the look; Silhouettes stands flat black outlines of the same plants in every look, the Realistic look included, as a section drawing shows them. The choice is kept with the section, so Update applies it again, and any one side view can be switched afterwards with Draw as in the properties panel. A plant with no side view in the library is left out and named.
Terrain behind the cut draws the ground beyond the cut face the way an elevation shows it: the surface is cut again along lines parallel to the cut, evenly out to the depth of view (Terrace lines says how many) and once through every plant's own ground, and each terrace is drawn back to front in the paper colour with an edge that fades with distance. A nearer rise hides what stands behind it, a tree on higher ground stands on the terrace through its own footing, and a building wholly behind the cut stands on its terrace at the height you typed, masking the ground and plants behind it unless a taller one rises beyond. Untick it to draw the cut face alone.
The optional datum adds an elevation axis with labels at an interval you type, or one picked from the range; the optional label letters the cut's arrows and titles the section, and the next section's letter follows on.
The cut line's look is set in the same window: its stroke width, the length of each arrowhead, the tail from the cut's end out to the arrowhead, and the line style of the cut itself (its tails and arrowheads stay solid).
Border around the section draws a rectangle round the view and its labels at a margin and width you set; it is part of the group.
The section lands on a layer of its own (Section A-A) as ordinary shapes,
side views and text, grouped: click any piece and the whole section is selected, so it drags
as one; click the same piece again, or Ctrl+click a piece, to select just that
piece.
Explode, beside the tools on the DRAW tab, frees the pieces to edit one by one; Undo puts the group back. The cut line, its arrows and letters are a group of their own on the plan, on a layer of their own (Section A-A cut line), so the view's layer can be hidden, faded or restyled while the cut stays marked on the plan; a new letter renames both layers.
Nothing is linked afterwards: editing the plan or moving the cut line does not redraw the section by itself.
To change a section, double-click any piece of it or of its cut line. The window opens again with the settings the section was made with, and Update rebuilds it from the plan as it is now, in one undo step. The section stays where you dragged it, and the cut follows the cut line to wherever you dragged that, so moving the line and updating cuts the plan in the new place. A changed letter renames the section's layer; the next section's letter stays as it was.
The rebuild makes every piece afresh, so a piece you changed by itself goes back to how the section draws it. An exploded section is plain shapes and text and no longer opens, and neither does a section placed before sections kept their settings: draw those again.