Manage Scene Layer Cache but still missing model

[MCh]

Hello Everyone!

I've published multipatch using 'Share As Web Layer' in ArcGIS Pro and then got 2 items in ArcGIS Online (‎Scene layer (hosted) and Feature layer (hosted))
What I want is to add more multipatch record into this, like appending more record.

So I used 'Update Data' in ArcGIS Online for Feature layer (hosted) by adding new multipatch in .gdb zip file.
The record in Feature layer (hosted) attribute data show up perfectly fine.
Then I go to Scene layer (hosted) to 'Rebuild Cache' in order to refresh the visualization of the multipatch model I just added.
BUT!! Nothing has changed..no geometry or any model has been shown up on the scene!
I've try every method in building cache, like Full Cache, Partial or Select Layer.

Is there anyone who used to experience this? Please help!

[RussRoberts]

The feature may have a different elevation and might be placed below the ground. Do you see the feature if you bring the scene layer into Pro?  If you can share the scene layer and feature layer I can take a look. 

[MCh]

Thank you @RussRoberts
I've already checked underground navigation in ArcGIS Scene Viewer both tilt and rotate but see nothing.

So I went back to ArcGIS Pro to check their elevation again by dragging Scene layer (hosted) service into ArcGIS Pro and use 'Move to' editing tool to check.
What I found is the first building record has Z value 5.54m and the second building I appended has Z value -0.15m. So, I adjusted the second one to 5.54m and saved edit. Then went back to ArcGIS Online and Rebuilt Cache for Scene layer (hosted) again.
After that, I refreshed the web scene and all the building finally shown up!

However, I don't understand why this issue happen because, as the picture below, both building are not that difference in height before they were appended together.
I can display them perfectly fine together with absolute height in properties setting.

What should I do next if I want to append more buildings into this same service?
Do you have best practice for this?
Thank you in advance and thanks for making me discover this issue.

[RussRoberts]

I would recommend using Pro to make the edits to the feature layer vs. append. Pro could be sending more information about the placement vs. taking the feature from the feature class and appending it.

If these are just 3D models(like gltf) you could use 3D Object feature class to publish a 3D Object feature layer and create an associate 3D Object scene layer. Then you can use Scene Viewer and upload the models and apply the placement. Then you will just need to rebuild the scene layer after the edits have been made.

[MCh]

@RussRoberts From your first paragraph, Do you mean using append tool in ArcGIS Pro to add more record into multipatch feature is better than using 'Update Data' button in ArcGIS Online?

I have already tried append tool in ArcGIS Pro to add new multipatch record into the multipatch service but I got an Error 999999.

[RussRoberts]

Not using append but using editor in Pro to add the new feature.