Eratic culling/clipping of 3D objects

Question

Hi,

I recently started having a look at the v1.0 version of the Unity SDK.  One test I've tried involved taking some 2D building polygons, heighting those from a terrain, extruding them into 3D building objects and then writing those to i3s.  This has then been opened in Unity, via the Map Creator, as a new layer.  The objects appear as expected, in the correct location.  So far, so good.  However, when I move the viewport camera around - or navigate around when in Game mode, these generated building models will appear and disappear in quite an erratic way.  It's not just distance clipping and some parts of an individual model will remain the whole time whilst other parts appear and disappear.  Changing the camera parameters (particularly FOV) seems to have some influence on what is happening, but doesn't solve it.  So, I'm now wondering what to do about this.  Could the issue be relating to the set-up of the source i3s file?  I'm a bit puzzled as to why it's behaving in this way.

Regards

Guy Heathcote
Ordnance Survey

GuyHeathcote · Answer

OK, now that you've got me questioning whether the problem sat within FME, I've now tried using ArcGIS Pro to prepare and generate the i3s, using the exact same base data.  This...works properly, with no culling or object flashing!

So, yes, I'm now assuming that the problem relates to an issue with FME's i3s writer.  Well, either that, or I'm somehow using it incorrectly, even though I'm struggling to see what else it might require from me.  That's slightly disappointing, in that I don't currently have a single tool that can undertake the entire i3s creation process.  However, at least I now have the end result I was looking for.

GuyHeathcote · Answer

Thank you.  I've been using FME to prepare and bake the data into i3s.  That was the most obvious route to try first, as FME can read from our NGD Features API with ease (and I'm already used to doing that).  There doesn't seem to be much that can be configured with FME's i3s writer - so, I'm now wondering if I'm missing a prior stage, or whether I should be looking at a different tool?

I'll look into getting a screen capture for you.

Matt_Nelson · Answer

Yea changing the properties on the ArcGISCameraComponent will give you some freedom to update it, but my guess is that the i3s data isn't baked correctly with it's LOD data so when we try to load a different LOD we aren't grabbing the right now.

Additional things you could provide to help diagnose the issue:
1. What tool are you using to bake the data? If you could provide a bit more details on that it would be good

2. Providing a short video showing the loading might help too