Precision

Overview

The .duc format achieves infinite precision by decoupling an element’s original physical measurement from the active viewing scale of the canvas.

Unlike traditional graphics formats that suffer from floating-point degradation when zooming in or converting units, .duc guarantees that an element’s original measurement is never corrupted.

The Foundation of Infinite Precision

The infinite precision of the .duc format relies on a core architectural principle:

Precision comes from recording the scope in which an element was created, preserving its original measure intact regardless of how or where it is rendered.

Even when looking at a document objectively, outside of user zoom interactions, an element’s true magnitude is defined by its creation scope. Whether an engineer draws a micro-chip trace in nanometers (nm) or a highway bridge in kilometers (km), the original measurement is recorded in that scope and preserved forever.

RawValue vs ScopedValue

To enforce coordinate integrity at the engine level, .duc distinguishes strictly between two types of numeric values:

1. RawValue (Immutable Original Measurement)

RawValue represents the immutable, exact physical measure of an element as defined when created in its native scope.

• Immutability: RawValue is never mutated or re-calculated when panning, zooming, or changing document display units.
• Lossless Storage: Stored inside .duc database tables as the ground truth of geometric state.

2. ScopedValue (Superficial Visual Scaling)

ScopedValue is an ephemeral, calculated value generated dynamically relative to the active canvas scope and viewport zoom.

• Superficial Scaling: ScopedValue exists solely for rendering, grid snapping, and UI display.
• Zero Side Effects: Computing a ScopedValue never alters or degrades the underlying RawValue.

export type PrecisionValue = {
  /** The immutable raw value of the element in its native scope */
  value: RawValue;
  /** The calculated value relative to the current active scope */
  scoped: ScopedValue;
};

Why Scaling Is Always Superficial

When working across different scopes or converting between Metric and Imperial systems, the engine calculates a translation factor between the element’s creation scope and the target scope:

translationFactor = ScaleFactor[providedScope] / ScaleFactor[currentScope]

scopedValue = rawValue * translationFactor

Because this calculation only produces a transient ScopedValue, the raw value of the element is never touched.

Even if an element is rendered at micro-scale or macro-scale through millions of zoom operations, returning to the element’s native scope yields its exact, uncorrupted RawValue.

Decimal Tolerances & Adaptive Grids

In addition to structural RawValue immutability, .duc supports configurable precision settings stored within duc_global_state and duc_local_state:

• Decimal Precision (decimal_places): Controls display rounding tolerance for distance measurements, coordinate readouts, and geometry serialization without affecting stored raw coordinates.
• Adaptive Grid Snapping: Adjusts reference grid resolution dynamically based on scope_exponent_threshold as the user zooms in or out, maintaining sub-millimeter snapping precision.

Summary of Precision Guarantees

1. Native Creation Scope: Every element records the scope in which it was authored.
2. Immutable Ground Truth: RawValue stores the exact physical measure and remains immune to floating-point drift.
3. Superficial ScopedValue: Canvas operations and zoom transformations compute transient ScopedValue instances on demand.
4. Multi-Scope Coexistence: Microscopic details and astronomical structures coexist in the same .duc container without precision loss.