In construction, Control is the basis of layout. It is a layout of various points that each trade uses to accurately lay out their elements per the field-approved documents.
How does Siteaware use control?
Siteaware requires control points in each scan to assist with two aspects of the verification process:
- Control provides additional accuracy to the digital twin, helping achieve up to 1/8" accuracy.
- The control points are user to align the digital twin to the physical jobsite.
What are the different ways to set control for Siteaware?
| Control Method | Minimum Achieveable Tolerance | Advantages | Disadvantages |
|---|---|---|---|
| Total Station Surveyed GCP Stickers | 1/4" | Very acurate | Requires additional surveyor points. |
| Manual Offset of Grids/Columns | 1/2" | No surveyor required | No global control, potential for manual error |
| RTK Surveyed GCP Stickers | 3/4" | No surveyor required, Independent measurement | Measurements are less accurate than Total Station |
Total Station Surveyed GCP Stickers
Placing control stickers directly on the deck and surveying them with a Total Station is the most precise method for measuring control. This method is highly effective for most projects because it provides a balance of accuracy (up to 1/4"), familiarity, and simplicity to the control process.
Manual Offset of Grids/Columns
For project teams that don't have the budget for a surveyor, they can rely on manual offsets to place control using existing building features, such as column grids, to establish the control point locations. While this approach eliminates the need for a surveyor, it increases the risk of manual error. Even minor misplacements of the control stickers can add up over long distances, resulting in a lower-accuracy digital twin (minimum achievable tolerance is 1/2"). This method also relies on the accurate placement of the columns or column grids, preventing Siteaware from verifying the deck globally, and can introduce additional errors if a column is already placed incorrectly.
RTK Surveyed GCP Stickers
This method is similar to the Total Station method but utilizes an RTK to survey the points. While this method is more cost-effective than a Total Station, the accuracy of the control point locations is lower (minimum achievable tolerance is 3/4"), resulting in a higher minimum achievable tolerance.