Wall Stationing lets you station the laser tracker by holding the reflector against walls that already exist on site, so you can print without surveyed control points. Scan three or more points on each of at least two walls that run in different directions, tap Station, and the FieldPrinter system works out where the tracker is.
Wall Stationing is in Beta and is turned on by request. To use it, contact Dusty Support at support@dustyrobotics.com or (510) 210-3658.
If your jobsite has surveyed control points, use them. Stationing from surveyed control is the most accurate method. Wall Stationing is for the rooms and jobsites where that control doesn't exist or can't be reached.
When to use Wall Stationing
Wall Stationing fits these situations:
- Surveyed control points were never set on the floor, or the surveyor hasn't been to the site yet.
- The control points exist but you can't see them from the printing area because walls have gone up since they were set.
- You're doing tenant improvement (TI) or renovation work where the walls are already built and they appear in your layout. Scan two walls in a room, station, print that room, then move to the next one.
Compared with corner control jigs, Wall Stationing needs no jig and works on walls that meet at any angle, not only 90° corners.
What you need
- Dusty App and FieldPrinter software version 2.20 or later. If you're on an older version, see How to Update the Dusty App and FieldPrinter Software Version.
- Radio 2 or Radio 3. Wall Stationing uses the tracker's tilt readings (pitch and roll), which Radio 1 can't provide. If your radio doesn't support it, the Dusty App tells you Wall Stationing isn't available; contact Dusty Support about a newer radio.
- Wall Stationing turned on for your system. Contact Dusty Support (above).
- A layout that contains the walls you plan to scan. Every wall you scan on site must exist as a line in your layout file.
- At least two walls that aren't parallel. If every wall you scan runs the same direction, the tracker's position along that direction can't be solved. Walls close to perpendicular give the best results.
- A roughly level tracker. Both tilt values (L and T) on the radio's level screen should be below 90. If the tracker is too tilted, the Dusty app shows a warning. See How the Laser Tracker Knows It Is Level.
- The blue ring reflector that came with your FieldPrinter. The Dusty app automatically accounts for the 3/4" between the center of this reflector and the wall. A different reflector size gives wrong results.
Recommended: Wall Stationing trusts the walls as built. Work from an as-built layout file, or tape-check the walls you scan against your layout before printing.
How to scan and station from walls
Set up the tracker
Set the tracker up on its tripod the same way you do for any stationing and level it. See How to Level the Tripod for Accurate Printing.
Power up the system
Turn on the FieldPrinter, tracker, radio, and tablet. Connect the Dusty App to the FieldPrinter and confirm the FieldPrinter is connected to the radio.
Scan your first wall
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In the Dusty App, open the left side panel and tap Setup > Stationing > Wall Stationing (Beta).
Wall Stationing start screen in the Dusty App. -
On the layout, select the wall that matches a physical wall on the jobsite, then tap Add.
Dusty App with a wall labeled Layer 1122 selected on the layout. Add button to include the selected line for Wall Stationing. Dusty App showing Wall 1 added. -
Hold the reflector flush against the wall surface and tap Scan.
Hand holding the reflector flush against a wall surface, with the tracker laser visible on the reflector. Dusty App showing Wall 1 with 1 scan recorded. -
Move along the wall and scan at least three points. Spread them out: points far apart along the wall give a more stable result than points clustered together. For each wall, the Dusty App shows how many scans you've taken and the spread, which is the maximum distance between scanned points along the wall.
Dusty App showing Wall 1 with 3 scans recorded, a spread of 2 feet 6 inches, and a green checkmark indicating the wall has enough data.
Scan a second wall
Select a second wall that runs in a different direction from the first and tap Add. Scan at least three points along it, again spread apart.
The two walls must not be parallel. If they are, you'll see a "Parallel lines" error (see Troubleshooting below).
You can scan more than two walls. The result is fit across all of them, and if the as-built distance between two walls doesn't match your layout, the Dusty App shows the mismatch in the results.
Station and review your results
Once you have at least three scans on each of at least two non-parallel walls, tap Station. The FieldPrinter system computes the tracker's position and orientation and shows the tracker location on the layout.
After stationing, the Dusty App shows a difference value for each scanned point: how far that point sits from its wall in the layout after the fit. Look for any scan whose value is much higher than the others. One bad scan — a bump in the wall, a piece of blocking, a point taken on the wrong wall — can shift the whole result. If a wall has an outlier, remove that wall and rescan it.
If you're using a verification reflector, set it up and scan it now (see How to Set Up and Use the Verification Reflector). Then place the reflector on the FieldPrinter, tap Start Reflector, and print your layout.
Troubleshooting
When Wall Stationing can't produce a result, the Dusty App shows a message that says what went wrong. Here is each message and what to do:
Parallel lines — Every wall you scanned runs in the same direction, so the tracker's position along that direction can't be determined. Scan a wall that runs in a different direction.
Symmetric geometry — Two tracker positions fit your scans equally well. This happens when the walls you scanned form a symmetric pattern, such as two lines crossing in an X. Scan another wall to break the symmetry, or use the cut tool in the Dusty App to cut the layout lines into shorter, distinct lines.
Reflector offset at shallow angle — The tracker is nearly in line with one of the walls you scanned, so the system can't tell which side of that wall the reflector was on. Scan a different wall, or move the tracker so it isn't looking straight down the wall.
Tracker too tilted — The tracker isn't level enough. Level the tracker and try again.
Reflector not in view — The tracker couldn't see the reflector when you tapped Scan. Clear the line of sight between the tracker and the reflector, then scan again.
Tips for accurate results
Spread your scans along each wall. Three points spaced 10 feet apart (20 feet end to end) beat three points within a few feet of each other.
Scan more than two walls when you can. Two is the minimum. A third wall strengthens the result and reduces the chance of a "Symmetric geometry" error.
Pick walls close to perpendicular. Walls meeting at roughly 90° constrain the result best. Anything between 45° and 135° works; closer to 90° is better.
Check the difference values before you print. If one scan on a wall is far off from the rest, remove the wall and rescan it.
Scan the same spots when you come back. If you'll print in this area again, scan in similar places on the same walls for the most repeatable results, especially if the walls are bumpy or uneven. Another option is to create control points where your printed lines intersect and station from those on your return.
Use surveyed control when it's available. Wall Stationing is built for rooms without usable control. On large jobsites, and on projects that need higher precision such as industrial automation and data centers, surveyed control points are the right choice.