WorldScaleSceneView - Graphics smaller than real world property boundary in AR view

[nvsraju0979]

I am building an iOS app using ArcGIS Runtime SDK (UIKit) that shows property parcel boundaries in AR using WorldScaleSceneView.

Problem: When basemap is visible, the graphic EXACTLY covers the property boundary on the basemap. But when I reduce the basemap opacity to 0, the graphic appears SMALLER than the actual real world property.

Property Details example sample data:

• Real world size: ~3 acres (~123m x 123m)
• Coordinate system: WGS84 (WKID 4326)
• Coordinates are correct (verified on basemap)

Sample Coordinates:

rings: [    [78.275931, 17.442276],    [78.275931, 17.441165],    [78.277095, 17.441165],    [78.277095, 17.442276],    [78.275931, 17.442276]]

My Current Setup:

// Scene setup
let scene = AGSScene(basemapStyle: .arcGISImageryStandard)
scene.addElevationSource()
scene.baseSurface?.opacity = 0
arView.locationDataSource = AGSCLLocationDataSource()
arView.translationFactor = 1

// Graphics overlay setup
boundariesGraphicsOverlay.sceneProperties =
AGSLayerSceneProperties(surfacePlacement: .drapedFlat)

// Symbol
AGSSimpleLineSymbol(
style: .solid,
color: UIColor(red: 1.0, green: 1.0, blue: 0.0, alpha: 1.0),
width: 5
)

What I Have Already Tried:

1. Verified coordinates are in WGS84 ✅
2. Added elevation source ✅
3. Set translationFactor = 1 ✅
4. Set surfacePlacement = .drapedFlat ✅
5. Verified graphic fits basemap exactly ✅

Questions:

1. Why does the graphic appear smaller in real world compared to basemap?
2. Is there any additional configuration needed for WorldScaleSceneView to render graphics at true 1:1 real world scale?
3. Does translationFactor need to be calculated differently for property boundary

[Ting]

One thing I'd like to confirm: when you set the basemap to translucent, say opacity = 0.5, does the basemap (and graphics) align with the real world well?

Generally speaking, world scale AR only  works well in close distance, as the vanishing point of the scene and the graphics might not be the same of the AR camera. Thus, if the graphics are quite far away from the device (say > 50m away), I can imagine that the graphics show up smaller than what the real world field patches.

I'll also check with our 3D folks to get a better understanding on this before I respond with more details…

[nvsraju0979]

Thank you for reply @Ting 

When we set the basemap opacity to 0.5, the alignment with the real world appears to be fine.

However, we are noticing that the graphics look significantly smaller compared to the actual real-world property, even when we are physically close to the location during testing. Please refer to the attached screenshots for reference. 

As you can see in the images i shared, while the positioning appears roughly aligned, the boundary/graphics are not matching the real-world property in terms of scale. The graphics look noticeably smaller compared to the actual property, even though we were close to the location during testing.

Please let me know if you need any additional information.

[nvsraju0979]

@TingI wanted to check if there are any updates regarding the question I posted earlier. Please let me know whenever you have more details.