MSFT_lod extension load error

Questions
1

Yo @bghgary …

UPDATE: Yep there is an issue for me with MSFT_lod and recursive error in Sandbox

MSFT_lod snippet:

{
      "mesh": 0,
      "rotation": [
        0.0,
        0.0,
        0.0,
        -1.0
      ],
      "name": "Broadleaf_Desktop_LOD0",
      "extensions": {
        "MSFT_lod": {
          "ids": [
            2,
            3
          ]
        }
      },
      "extras": {
        "MSFT_screencoverage": [
          0.5,
          0.25,
          0.13
        ]
      }
    }

Sandbox Error:

53%20AM
Screen Shot 2019-03-15 at 2.48.53 AM.png1405×962 44.2 KB

Test Tree GLTF

TestTree.zip (3.2 MB)

Also… I dont think the MSFT_lod is taking into account the you break up submeshes into a bunch of primitives… So even my LOD meshes are getting split into a bunch of separate meshes.

Can you please take a look this one as well. Thanks Bro :slight_smile:

2

Sorry for the slow reply.

The problem is that the asset is pointing to node 2 twice. Once from node 0 and once from the MSFT_lod extension. This isn’t allowed. If I remove 2 and 3 from node 0’s children, then it renders.

image
image.jpg1044×1110 196 KB

3

So if you make a LOD out of a node you have to remove it from whatever parent node’s children list. Ok… But i still don’t see the LOD switching when scrolling in and out in the sandbox… Also it throws the new LOD0 mesh OUT of it parent into the main scene hierarchy.

4

The MSFT_lod implementation in Babylon is currently for progressive loading. There is a backlog item to implement the rendering version. Add support for loading MSFT_lod extension as rendering LODs · Issue #4818 · BabylonJS/Babylon.js · GitHub

5

I am currently trying to implement rendering myself… I got it going pretty good EXCEPT… I cant figure out how to convert screen coverages to babylon LOD distances… Can you please help me with screen coverage to distance calculations ???

6

@deltakosh had some ideas when we talked about it.

7

to be performant we need to use weblg queries that will give us the screen coverage of a mesh. Then we can convert that number of pixels to a threshold like a ratio to the overall number of pixels

8

Hi just use the tree as an example, can anybody show more detail explnation and any exmaple link in playground
?

9

can you please give an example about how to use MSFT_lod extension with a playground link?

2 Likes
10

I’m not sure what you are looking for. The MSFT_lod extension is a loader extension. Unless you want to stop at a particular LOD or something similar, there is nothing special to do with the code. Perhaps you want an example of an asset with LODs?

11

@moxierichard I created a demo and doc page. Does this help?

1 Like