PDF Underlay
Place a survey, architect plan, or site map as a scaled tracing layer and draw your design on top.
A PDF underlay lets you import an existing survey drawing, architectural plan, or site map and use it as a scaled reference beneath your design. During import you set the scale against a known real-world dimension so that snapping, measurements, and area calculations reflect on-site distances. After placement the underlay is locked, and you can fade it back or hide it at any time from the Layers tab without affecting your design. This is a common starting point for projects where a client has supplied an existing plan.
Open the Underlays import wizard
In the top toolbar, click Import and choose Underlays from the dropdown. The Underlays import wizard opens with a four-step progress indicator: File, Adjust, Size, and Finish.
For the sharpest rendering, always use the original vector PDF rather than a scanned photocopy. Scanned PDFs are rasterized at a fixed resolution and appear blurry at high zoom levels.
Import the PDF
Go to File > Import > PDF Underlay. A file picker opens — select your PDF file.
If the PDF has multiple pages, a page selector appears. Choose the page that contains the site plan you want to trace. Click Import.
The PDF is rasterized and placed at the center of the canvas on a new locked layer named after the file.
For best rendering quality, use the original PDF rather than a scanned photocopy. Scanned PDFs may be blurry at high zoom.
Reduce opacity for tracing
The PDF underlay is placed at full opacity. To make tracing easier, reduce the opacity:
1. Click the underlay layer row in the Layers panel to select it 2. In the Inspector, drag the Opacity slider to 30–50%
The PDF fades back, making your drawn lines visible against it.
You can import different pages of the same PDF as separate underlays. Repeat the import and choose a different page each time to layer a floor plan alongside an elevation drawing, for example.
Calibrate the scale
After import, the PDF is placed at an arbitrary pixel size. To align it with real-world coordinates:
1. Go to Tools > Calibrate Scale (or click the Calibrate Scale tool in the toolbar) 2. Find two points on the PDF with a known real-world distance — for example, a boundary line labeled 10 m 3. Click the first point, then click the second point to draw the measurement line 4. A dialog appears — type the real-world distance (e.g., 10 m) and press Enter
The PDF and canvas scale are aligned. All measurements from this point forward are accurate.
Use a long, clearly labeled dimension line on the plan for calibration — the longer the reference line, the more accurate the calibration.
Clip to a selection area
If the PDF contains more area than you need — for example, a full site plan where you only need one garden — you can clip the underlay to show only the relevant portion:
1. Unlock the underlay layer 2. Select the PDF underlay entity 3. In the Inspector, click Clip to Selection Area 4. Draw a rectangle over the area you want to keep 5. The PDF is cropped to that rectangle
Clipping reduces visual noise when working in a specific zone of a large plan.
Use the longest clearly labeled dimension line on the plan. A longer reference span reduces the effect of any rounding error in the measurement.
Finish and reduce transparency
On the Finish step, click Finish Import to place the underlay. It is added below your design content and locked by default. To fade it back for comfortable tracing, open the Layers tab in the Inspector, expand the underlay row in the Underlays section, and raise the Transparency slider to roughly 30–50%.
Start tracing your design
With the scale set and transparency reduced, use any 2D drawing tool — Polyline, Bezier, Rectangle, Arc, or the hardscape wizards — to trace the site boundaries and existing features. Snapping works relative to the scaled canvas, so measurements and area calculations automatically reflect real-world dimensions as you draw.
Use the Vectorize (Smart Trace) tool to automatically detect and vectorize outlines from an image, saving time on complex boundary shapes.
PDF pages are rasterized at up to 4096 px on the longest edge. Very large-format PDFs (A0 surveys, for example) may be slightly downsampled to stay within this limit. If line text on the PDF looks blurry, zoom in on the canvas — the underlay is rendered at its full rasterized resolution and sharpens as you zoom.
Straighten and scale the page inside the import wizard before placing it. Use the Straighten and Deskew Perspective controls on the Adjust step, then set the scale on the Size step. If a placed underlay turns out wrong, delete it from the Layers tab and re-import with the corrected adjustments.
Frequently Asked Questions
The PDF plan is rotated — how do I straighten it?
Straighten it on the Adjust step of the import wizard before placing it, using the Straighten control or the Deskew Perspective tool. If a placed underlay is misaligned, delete it from the Layers tab and re-import the page with the correct straightening applied.
Can I use more than one page of the same PDF in a single drawing?
Yes. Each import brings in one page as a separate underlay. Go to Import > Underlays, choose the same PDF file, and select a different page. Each page appears as its own underlay in the Layers tab so you can control its visibility and transparency independently.
Will the PDF underlay appear in my exported PDF or presentation output?
A visible underlay is included in all exports and renderings. If you want to export only the design without the background plan, hide the underlay from the Layers tab before exporting.
My PDF is large and the page selector is slow to appear — is something wrong?
No. Thumbnail generation processes every page of the PDF in your browser before the page selector opens. Large multi-page PDFs (50+ pages) can take 10–20 seconds. The thumbnails appear progressively as each page renders — you can scroll and click a page as soon as its thumbnail loads without waiting for the rest.
How reliable is the scale I set?
The scale depends on the quality of the reference dimension you pick. A longer reference line (at least one-quarter of the plan width) gives the best result. Minor differences in the original survey or printing can introduce a small error — treat the scaled plan as a helpful guide and always verify critical measurements on site.