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Detect obstacles automatically

Detect obstacles finds chimneys, vents and skylights inside the faces you drew from Google’s height data. Fill roof runs it the first time on its own. Check the result against the image and add what it missed.

Anything that sticks up from a roof face — a chimney, a vent, a skylight frame — shows on Google’s height map as a bump. Cali-Graf looks for those bumps inside your faces.

Run it

  1. Draw the roof faces

    Obstacles are searched only inside the faces you drew.

  2. Press Detect obstacles

    Pick Obstacle and press Detect obstacles, or press ⌥O in any tool. The found obstacles appear on the roof as rectangles and circles.

  3. Check against the image

    Zoom in and compare. Delete what isn’t an obstacle, adjust the size of what is, and draw what was missed — see Add chimneys, vents and skylights.

With Fill roof

The first time you press Fill roof (X), Cali-Graf looks for obstacles first and lays the panels around them. After that it doesn’t search again by itself — run Detect obstacles if you changed the faces.

What it can miss

  • Small plumbing vents and flat roof hatches that barely rise above the roof.
  • Anything under trees or on a blurry, low-quality image.
  • Changes made after the image date.

Obstacles it already found or you drew aren’t added twice.

What you seeWhat to do
Draw the roof faces first — obstacles are searched inside themTrace the faces with Roof, then run it again.
No new obstacles found on the drawn facesNothing new stands out on the heights. If you see a vent on the image, draw it by hand.

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