Developing an area/volume calculator in 1C-Bitrix

Area/Volume Calculator Development for 1C-Bitrix

An area and volume calculator is a fundamental tool for websites of construction, finishing, cleaning companies and materials manufacturers. The task looks straightforward at first glance: the user enters dimensions and gets an area or volume. In practice it is more complex: different room types are needed, deductions for openings, non-standard shapes, summation of multiple rooms and automatic transition to cost calculation.

Geometric Formulas

A complete set of formulas for construction calculations:

namespace MyProject\Services\Calculators;

class GeometryCalculator
{
    // Room areas
    public static function rectangleArea(float $width, float $length): float
    {
        return $width * $length;
    }

    public static function lShapeArea(float $w1, float $l1, float $w2, float $l2): float
    {
        // L-shaped room: two rectangles
        return self::rectangleArea($w1, $l1) + self::rectangleArea($w2, $l2);
    }

    public static function circleArea(float $radius): float
    {
        return M_PI * $radius * $radius;
    }

    public static function triangleArea(float $base, float $height): float
    {
        return 0.5 * $base * $height;
    }

    // Wall area of a room (with deduction for openings)
    public static function wallArea(
        float $perimeter,
        float $height,
        array $openings = [] // [{width, height}, ...]
    ): float {
        $totalWall   = $perimeter * $height;
        $openingsArea = array_sum(array_map(fn($o) => $o['width'] * $o['height'], $openings));
        return max(0, $totalWall - $openingsArea);
    }

    // Volumes
    public static function boxVolume(float $width, float $length, float $height): float
    {
        return $width * $length * $height;
    }

    public static function cylinderVolume(float $radius, float $height): float
    {
        return M_PI * $radius * $radius * $height;
    }

    // Roof area accounting for slope
    public static function roofArea(float $horizontalArea, float $slopeDegrees): float
    {
        $slopeRad = deg2rad($slopeDegrees);
        return $horizontalArea / cos($slopeRad);
    }
}

Multi-Room Calculator

Calculation for multiple rooms with accumulated totals:

class RoomCalculator {
    constructor() {
        this.rooms = [];
    }

    addRoom(params) {
        const room = {
            id:      Date.now(),
            name:    params.name || `Room ${this.rooms.length + 1}`,
            floor:   params.width * params.length,
            ceiling: params.width * params.length,
            walls:   this.calcWalls(params),
        };
        this.rooms.push(room);
        return room;
    }

    calcWalls(params) {
        const perimeter = 2 * (params.width + params.length);
        const totalWall = perimeter * params.height;

        const openingsArea = (params.doors || []).reduce((sum, d) => sum + d.width * d.height, 0)
            + (params.windows || []).reduce((sum, w) => sum + w.width * w.height, 0);

        return totalWall - openingsArea;
    }

    getTotal() {
        return {
            totalFloor:   this.rooms.reduce((s, r) => s + r.floor, 0),
            totalCeiling: this.rooms.reduce((s, r) => s + r.ceiling, 0),
            totalWalls:   this.rooms.reduce((s, r) => s + r.walls, 0),
            rooms:        this.rooms,
        };
    }

    removeRoom(id) {
        this.rooms = this.rooms.filter(r => r.id !== id);
    }
}

Visual Parameter Input

The challenge lies in UX. Users don't always know exact dimensions. Several approaches help:

Standard sizes. Selection from a reference guide: "standard panel apartment", "studio 25m²", "one-bedroom 38m²". Dimensions are auto-filled with the option to adjust.

SVG room diagram. An interactive drawing where the user clicks on a wall and enters a dimension. Implemented with SVG + JavaScript, no external dependencies.

Layout upload. The user uploads a photo or scanned floor plan; a manager processes it manually. A hybrid approach for complex objects.

Bitrix Catalog Integration

After calculating the area — automatic transition to material selection:

// AJAX handler: select the required quantity of products by area
public function suggestMaterialsAction(float $area, string $materialType): array
{
    $norm = MaterialNormRepository::getByType($materialType);

    $rawQuantity = $area * $norm['consumption_rate'] * $norm['waste_factor'];
    $packages    = ceil($rawQuantity / $norm['package_size']);

    // Check stock availability
    $product = \CCatalogProduct::GetByID($norm['product_id']);
    $inStock  = (int)($product['QUANTITY'] ?? 0);

    return [
        'product_id'   => $norm['product_id'],
        'product_name' => $norm['product_name'],
        'packages'     => $packages,
        'in_stock'     => $inStock,
        'enough_stock' => $inStock >= $packages,
        'can_order'    => true,
    ];
}

Saving and Printing Results

For complex objects, users want to save their calculation. Implementations:

Link with parameters — the calculation is encoded into URL parameters, and the link is saved or shared:

const paramsStr = btoa(JSON.stringify(calcParams));
const shareUrl  = `${window.location.origin}/calculator/?calc=${paramsStr}`;

PDF export — server-side generation via the TCPDF or mPDF library installed through Composer in /local/:

$pdf = new \TCPDF();
$pdf->AddPage();
$pdf->writeHTML($this->renderCalcHtml($calcResult));
$pdf->Output('calc_result.pdf', 'D'); // D = force download

Email with results — sent via \Bitrix\Main\Mail\Event::sendImmediate().

Timelines

Calculation accuracy is paramount. An error of 10% on the low side means the client buys additional materials at a different (often higher) price and comes back dissatisfied. It is better to add an explicit 5% buffer than to underestimate and lose trust.