Road Restraint — guardrail and barrier

What it does

CAPCAD_RESTRAINT draws a lateral restraint device — a metal guardrail, a concrete barrier or a generic object — as a polyline parallel to the alignment, plus the two terminal blocks at the ends.

The chain is always the same:

1. Two points. The positioning method you chose produces a start and an end point: clicked, or computed from a station and a length.
2. Projection onto the alignment. The two points are projected perpendicularly onto the alignment (a 500-unit reach) and ordered by station.
3. The stretch. The part of the alignment between the two stations becomes the device's reference line.
4. The offset. That stretch is shifted sideways by the offset. A positive offset draws the body to the right of the alignment's increasing direction (CapCad calls that Increasing); Decreasing puts it on the left.
5. The metreage. Through a curve, the parallel comes out longer or shorter than the alignment stretch. The body is then re-anchored at the start point and rounded to the object's multiple: 4 m (one beam) for the guardrail and for the custom object, 1.50001 m for the barrier — the extra 0.00001 keeps the length from landing exactly on a linetype pattern boundary.
6. Terminal clearance. If the terminals must not overlap the body, it shrinks by 24 m — three 4 m beams at each end — so that the blocks occupy the extremities.
7. The terminals. Two blocks are placed at the ends of the body, facing outwards, scaled and stamped.

The body is drawn on the current layer. The batch insertion, and only it, resolves the layer from the action (DEFENSA_IMP, DEFENSA_MAN, DEFENSA_REM, DEFENSA_SUB of the active layer catalogue).

The Info tab of the form carries the glossary of terminal abbreviations the project uses, taken from the norm of the active country profile. The abbreviations are the ones the shipped block library is named after; the same glossary is behind See the accepted values (129) on the batch form.

Workflow

1. Run CAPCAD_RESTRAINT (or type DEF). The form opens beside the drawing.
2. On the Main tab, choose the positioning method (2, 3, 5 or 8) and fill its boxes. Clicking inside a box already selects the method it belongs to.
3. Choose the object (27, 28 or 29) and the offset: Detect from the point (11) measures the distance from the clicked point to the alignment, or Fixed (12) uses the value in 13.
4. Adjust the terminals (1, 16 to 20) and the body action (48, 49, 51, 52).
5. Click Insert (40).
6. In the point methods, the command asks for Ponto inicial and, in 2 points, also for Ponto extensão.
7. The command asks you to select the alignment — a polyline or a line.
8. The body is drawn, the embankment hatch is added if Add slope (54) is ticked, the terminal blocks are inserted, and the command line sums it up: body length, start and end station, direction, and how many terminals went in out of how many were planned.

The form stays open for the next stretch.

The Road restraint form

Numbers 1 to 95 run through the seven tabs of Road restraint; 96 to 132 are the batch insertion, further down. The screenshots are of a Portuguese session; the numbering is the same in both editions, and the tables give the English captions.

The Main tab, the form as it opens: method km to km, object Barrier, direction Increasing, action Insert.

Tab 1: Main

Positioning method (top left frame)

In both km methods, the command frames the view on the resolved stretch.

Alignment offset

In the point methods, the side of the clicked point decides the direction: a point to the left of the alignment makes the stretch Decreasing, one to the right, Increasing. Buttons 30 and 31 apply to the km methods.

Object, Direction, Characteristics

Body action, scale and slope

Terminals (right column)

Labels

The whole frame is not available in this version: nothing is written beside the guardrail.

Overlap and direction reference

One of the two buttons in the Terminal block overlapping the guardrail body frame must be ticked; if neither is, Insert warns that the overlap methodology must be selected and does not run.

Footer actions

When the command cannot resolve the stretch, the command line says why. The refusals are written in Portuguese in every language: selecione um método de posicionamento (choose a positioning method), informe a extensão (give the length), valores de km inválidos (invalid km values), impossível determinar — muito longe ou fora do eixo (cannot determine — too far or off the alignment), extensão mínima não atingida para os terminais (24 unidades), extensão provida muito pequena (menor que 4) (length given too small, under 4) and mesmo ponto inicial e final (OSNAP ligado?) (same start and end point — is OSNAP on?).

Tab 2: Utilities

The Utilities tab: editing restraints that are already drawn.

This tab is a second set of tools, for editing existing restraints rather than creating new ones. None of its controls is available in this version. The controls are: Insert block by 1 mid point + length (57); the Method frame with 2 points (58), 1 mid point + length (59) and its box (60), End + length (61), Round to multiples of (62) and its box (63), and Adjust terminal if present (64); the Replacement frame with Beams (65), Block (66) and its list (67) and Empty (68); and the buttons Insert block: guardrail/barrier transition (69), Insert terminal in existing restraint (70), Replace terminal in existing restraint (71) and Round existing length to multiples of… (72) with box 73, Include terminals (74) and Multiple mode (75).

Tab 3: Terminal blocks

The Terminal blocks tab: the names used when option Blocks (17) is ticked.

The Road restraint form stores nothing between sessions.

Tab 4: Options

The Options tab: units, length rounding and the list of automatically filled attributes.

The list of attributes filled automatically when the terminal block has them: LATITUDE, LONGITUDE, KM, DEF_LAT, DEF_LON, DEF_KM, DEF_TRAMO, DEF_FUNCAO, DEF_TERMINAL, DEF_ACAO, ACAO, TRAMO, FUNCAO, TERMINAL, DEF_EXT, DEF_TERM_INICIAL, DEF_TERM_FINAL.

Tab 5: Info

The Info tab: the text the form shows about the length rounding, and the glossary of terminal abbreviations with its norm reference.

This tab is text only; it has no controls.

Tab 6: Slope

The Slope tab: the four numbers of the hatch drawn together with the guardrail.

The four values are only used when Add slope (54) is ticked on the Main tab. The hatch is described in detail on the embankment hatch page.

Tab 7: Extra

The Extra tab: three maintenance utilities.

None of the three has any effect in this version: Redefine guardrail linetype (93), Redefine terminal block (94) and Insert Motiva layers (95).

How the options combine

The figures below were produced by running the command's own positioning engine on a 340 m sample alignment (a straight, a curve and another straight), in the km to km method, from 0.040 to 0.260 — a 220 m stretch of alignment.

Offset and direction

Offset 8 m, increasing direction: the body (orange) sits to the right of the alignment (dashed). Since part of the stretch is in a curve, the parallel came out at 221.08 m; rounded to multiples of 4 m, the delivered body is 220 m.

The same stretch in the decreasing direction: the body moves to the other side. On the inside of the curve the parallel shortens (219.24 m) instead of lengthening, and the rounding takes it to 220 m all the same.

Clearance for the terminals

With No under "Terminal block overlapping the guardrail body", the body loses 12 m at each end: from 220 m to 196 m. The two terminal blocks (blue arrows) sit at the ends of the body, facing outwards — the entry one at the lower station, the exit one at the higher.

Multiples per object

The rounding uses the multiple of the chosen object. On the same stretch, the raw 221.08 m parallel becomes:

The batch insertion

CAPCAD_BATCH_RESTRAINT draws a whole road's worth of restraint from a pasted table. It is the natural destination of the stretch table the restraint analysis produces.

The batch form: the text area on the left takes the table, and the lists on the right say which column is what.

Each line of the text area is a stretch. The columns are separated by tabs — pasting straight from Excel already gives you that — and each list on the right names the column letter (A, B, C…) that datum comes from. A line with no tab at all is silently ignored.

The command uses the project's alignment (it asks for no selection) unless Straight line (103) is ticked. Each stretch is resolved by the same chain as the interactive form, and the body plus the two terminal blocks go to the action's layer (DEFENSA_IMP, DEFENSA_MAN, DEFENSA_REM or DEFENSA_SUB).

The controls

An empty column list means column A. The letters are upper case: a lower-case letter points at no column and the cell is simply not found.

What interrupts a batch

Three situations stop the whole run (the lines already drawn stay): in Coordinates mode, a coordinate column past the end of the line; in Km mode, both station columns past the end of the line; and, also in Km mode, only one of them past the end. Single-line errors — a point that does not project onto the alignment, two coincident points, an offset that fails — are listed in the final report and the batch carries on.

Remembered between sessions

The Road restraint form stores nothing: it always comes back to its initial state (km to km, Barrier, Increasing, Insert, offset detected from the point, terminals on in System mode, overlap Yes, reference km direction, rounding to multiples of 4 on).

The batch form stores: the terminal-type columns (125, 128), the four coordinate columns (104 to 107), the two station columns (111, 112), the Km / Coordinates choice (110, 102), the LAT, LON / E, N choice (108, 109), Straight line (103), the terminal block mode (117, 118, 121), the two fixed names (119, 120), the two block columns (122, 123) and the attribute list (126). The Offset (98) and Action (99) columns are written but not read back on opening. The text area is restored from the exports folder.

Notes

• With System (16) ticked and the Start and End boxes empty, no terminal is inserted. In that mode the typed type is used as a block name, and an empty name resolves to nothing; the command line lists "block not found". Type the terminal abbreviation in both boxes, or choose Blocks (17) and use the names from the Terminal blocks tab, or choose Actions (18) to fall back to the default block DEF_TERMINAL_IMP.
• The terminal names come out crossed. The block called entry gets the value of the End box and the exit one the value of the Start box. If the two abbreviations differ, check which end each one appears at.
• The station stamped on each terminal is the other end's. DEF_KM and KM are read from the vertex opposite the one the block is inserted at.
• The guardrail is drawn on the current layer. Only the batch insertion resolves the layer from the action. If you want the body on a restraint layer, make it current before clicking Insert, or use the batch.
• The slope hatch drawn with the guardrail also goes to the current layer, unlike CAPCAD_ROAD_EMBANKMENT, which uses the TALUDE layer of the active catalogue.
• The km methods refuse the value zero, so a stretch starting exactly at km 0+000 cannot be typed. Use 2 points in that case.
• The km + length method mixes two station readings. The start point is looked up by the raw measure along the alignment, but the end is computed from the normalised station. On an alignment starting at km 0 with no station equations the two coincide; on any other alignment, the end of the stretch may come out displaced. Check the result when the alignment's start km is not zero.
• The batch insertion exists only in AutoCAD in this version; on the other CADs it reports itself as not available.