How do I create roof outlines using Track Outline and digitising?

Construct Roof > Track Outline

Track Outline creates the roof perimeter from which all roof geometry is generated. You can build outlines using actual measurements, by digitising/tracing underlay images (aerial photos, PDFs, architect plans), or combining both methods. The outline can represent wall perimeters (with eave overhang added later) or eave perimeters (with zero overhang).

When selecting Track Outline, the software asks if you want to continue a previous incomplete outline. This recovery feature helps if you made mistakes or cancelled before completion.

Select Yes to continue where you left off, or No to start fresh from the job origin (X,Y coordinates 0,0).

The main Track Outline dialog has two display modes:

Predefined direction buttons for quick input:

Quick entry shortcuts: Type U, D, L, or R in the distance field for Up, Down, Left, Right directions. Example: R5000 or R5M creates a right-direction line of 5000mm or 5 metres.

Distance units depend on your System Preferences settings:

Quick square outline: Type C (close square shortcut) in distance field and press Enter.

The pitch button allows multiple roof geometry options:

Curved roof options create rectangles representing flattened roof areas, perfect for ordering flat metal sheets that will be 'walked' onto curved roofs during installation.

When you only know Horizontal and Vertical dimensions (not direction and length), click H-V button:

The software shows two possible intersection points and lets you choose the correct one.

Locate Point on Screen: Use existing line endpoints to automatically fill H/V fields from job datum.

Measure button [m]: Ignores Z-axis when measuring, reporting distances on the flat construction plane.

When roof measurements are taken up the slope, use the pitch field to convert to horizontal distance:

If you don't know the pitch but have ridge-to-eave measurements, click the pitch calculation button:

The calculated pitch is inserted automatically, then combined with slope dimension to determine correct wall/eave line length.

For 3D roof models with field measurements, the software converts slope distances to flat distances:

Example: 27.5° pitch with 12000mm slope distance converts to 10644mm on the flat.

Imperial example: 6:12 slope with 39'5" converts to 35'2.75" flat distance.

The Options button sets line style, colour, and weight for roof outline construction lines. Especially useful when digitising over aerial images or PDF plans where background may obscure roof features.

The Options button provides direct access to Tools > Set Display options without exiting Track Outline.

Roof Wizard allows combining measurement entry and image digitising to create complete roof geometries. Use when not all dimensions are available but underlay images exist.

⚠️ Critical: Image files must be saved in the ..\User folder BEFORE starting. File names cannot contain spaces (use roof-picture.JPG, not roof picture.JPG).

The Enable Underlay button provides two image source options:

Places clipboard images directly into workspace at approximate scale. Works with:

⚠️ When pasting from clipboard, save the model when prompted. This saves the clipboard image as a JPEG file named <database name>-<model name>.JPG. If not saved, it becomes Temp.JPG and will be overwritten by subsequent clipboard operations.

Select previously saved images from the User folder. Images are sorted by type (BMP, TIF, JPEG) using the dropdown at bottom right.

For PDF documents with multiple pages, scroll through available pages and select the page showing roof geometry. Only one page can be viewed per Roof Wizard view.

Once selected, the image appears on screen at unknown scale - scaling to full size is the next critical step.

💡 The Enable button changes to Delete after image placement, allowing you to remove and replace underlay images.

Access via Scale Model button or Construct Roof > Underlay Image > Scale Image/Model menu.

Image must be scaled to full size using known reference measurements. Use the widest possible measurement span to reduce percentage error.

For best accuracy:

After scaling, verify accuracy using Chk Meas button. Select one of the longest known measurements to reduce percentage error.

The dialog shows X,Y,Z coordinates of start/end points and exact distance. Good accuracy example:
Known measurement 22,700, result 22737.2 - that's OK.

The [-] bonding button allows separate scaling in X, Y, and Z axes. Rarely used as scale is typically uniform across all axes.
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When captured images aren't square to X/Y axis, use Rotate Image to align without rotating the Construction Plane.

Process:

⚠️ Before digitising: You MUST scale the image using known reference lengths to work at full size.

For greater precision, reduce constraint values (e.g., 10mm or 1/2").

⚠️ Cannot use middle mouse button to 'snap' to image corners - images are pixellated, not vector-based.

For Close 2 Lengths, specify the final two line lengths and approximate intersection location and you get something like this:

Which is clearly not square, but in accordance with the dimensions specified.

💡 For regular shapes, input all but the last two lines, then use Close Square to let software determine final lines automatically.

Click Finish button or type F to complete outline definition. This draws the wall lines and opens the Roof Defaults dialog to define critical roof geometry aspects.
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Drone imagery can suffer from parallax error - distortion caused by viewing angles other than perpendicular to the roof.
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Prevention techniques:

Parallax distortion example:

⚠️ Ignoring parallax creates non-orthogonal roof edges unsuitable for metal panel cutting lists, though area calculations may still be acceptable for per-square estimates.
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The issue with ignoring the parallax error is evident in the following example:

(With apologies to JB)