Add new objects in a .custom-group entity of segment

[Algorush]

Need to merge this PR in 3DStreet first to respect elevation level of new adding objects. This branch was created to test the approach when adding objects from the New Entity panel. Described here: https://github.com/3DStreet/3dstreet-editor/issues/408#issuecomment-2080332617

[netlify[bot]]

✅ Deploy Preview for 3dstreet-editor-builds ready!

Name	Link
🔨 Latest commit	b836e0872072fb0718d3b0c6f9a14c5651c8170f
🔍 Latest deploy log	https://app.netlify.com/sites/3dstreet-editor-builds/deploys/662dbc370ba6940008f73edb
😎 Deploy Preview	https://deploy-preview-421--3dstreet-editor-builds.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[kfarr]

Checklist to complete v1: Checklist

• [x] Choose which branch we are using for this -- there are 2?
• [x] Errors while hovering for some objects - triage first
• [ ] Panel should be hidden behind a isBeta claim flag
• [ ] Review -- are these the layers that we need? Any missing? Any shouldn't be there?
• [ ] first option selected is blank
• [ ] incorrect scroll behavior - dropdown shouldn't scroll, should always be static at top of modal

LATER:

• LATER addlayerbutton needs focus state (implemented correctly on addlayerpanel closeButton)
• LATER Long-term should use a catalog.json format that is shared between core and editor. (Maybe even bring core into editor)
• LATER Long-term issue -- Hover preview – Is it always creating new entities or is it changing the value of 1 entity? Is it properly disposing of the gltf preview?
• LATER -- how to create input mechanism for user when placing an entity that has required properties (such as a src url when placing an image)
• need thumbnail preview

[Algorush]

Review -- are these the layers that we need? Any missing? Any shouldn't be there?

Still need to add layers (from Doc):

• intersection (I'm going to implement it as a new component - https://github.com/3DStreet/3dstreet/issues/438),
• Splat,
• Image - to see my work (Screenshot?),
• QR anchor (street-qr-anchor)

[Algorush]

LATER Long-term issue -- Hover preview – Is it always creating new entities or is it changing the value of 1 entity? Is it properly disposing of the gltf preview?

Just for information - there is a special entity for the preview, which is created when the panel is opened and when user hover over the cards, its properties change (mixin, position)

[Algorush]

Maybe we should add Segment Layer aslo? It could be just empty sidewalk/road/bike segment. But it's better to first create a segment component with approximate parameters: type (type from Streetmix) - road, sidewalk, bike path, ground, etc; elevation level -2, -1, 0, 1, 2; content (variantString from Streetmix) - for each type user can select variant from the list of variants, in accordance with the structure from segments-variants.js. Or we can in 3DStreet allow user to add any options that roughly correspond to the type of segment.

[Algorush]

Regarding the preview method - did we settle on the current method of previewing an element - appearing in the middle of a segment? So I can remove the old code related to the preview of the element 5 meters in front of the camera?

[kfarr]

@Algorush yes previewing on currently selected segment is good to start

[Algorush]

issues to fix:

• delete preview entity when closing the panel or assign an id. Now a new one is created every time the panel is opened
• I see strange duplicates of created elements inside a-scene
• determine the order of adding elements not inside the segment-parent - to buildings-parent, ... There is a small task here on how to do this so that buildings/elements are added to the right place on the scene and inside the scene graph

[kfarr]

close by #428