Linking PDF to 3D

Linking PDF to 3D Model

LocusBIM's core feature connects every markup you draw on a PDF floor plan to a precise position in the loaded 3D model — and vice versa. This bidirectional link is computed entirely offline using an affine coordinate transform you calibrate once per sheet.

Overview

• Sheet Calibration — registers the PDF coordinate space to 3D model space using two reference points.
• Per-markup linking — every markup drawn on a calibrated sheet automatically stores its 3D position.

Step 1: Open a Model and a PDF

Use File → Open Model to load a GLB file. Then use File → Open PDF to open the corresponding floor plan for the level shown in the model.

Step 2: Calibrate the Sheet

Go to Tools → Link Sheet to 3D… and follow the wizard:

1. Choose "Two-point calibration" (recommended).
2. Click a recognisable feature on the drawing (column grid intersection, room corner).
3. Switch to the 3D Viewer, hover over the same real-world feature, and enter its XYZ coordinates.
4. Pick a second reference point as far from the first as possible.
5. Enter the floor elevation (Z). Confirm to apply the calibration.

Step 3: Draw Markups

Select any markup tool and draw on the calibrated PDF page as normal. Each markup's centroid is automatically converted to 3D coordinates and saved to the database. Nothing extra to do.

Step 4: See 3D Markers

Switch to the 3D Viewer tab. A red sphere appears at each markup's 3D position. Spheres update in real time as you add or remove markups.

Navigating from 3D to PDF

Click any red sphere in the 3D viewer. The app automatically switches to the PDF tab, navigates to the correct page, and selects the linked markup in the sidebar.

Navigating from PDF to 3D

Right-click any georeferenced markup on the canvas. If the markup has a stored 3D position, the context menu shows Fly to 3D Position. Click it to animate the 3D camera to that location.

Recalibrating a Sheet

Open Tools → Link Sheet to 3D… at any time to update or replace the calibration. Existing markups retain their saved 3D coordinates — recalibrating only affects newly drawn markups going forward. Use the Clear button in the dialog to remove the calibration entirely.

Multi-level Projects

Each PDF page can have its own independent sheet transform. Open a different page and run the calibration wizard again to set the elevation and reference points for that level. Markups on Level 1 and Level 2 will both appear at their correct heights in the 3D viewer.