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Esri / i3s-spec

This repository hosts the specification for Scene Layers which are containers for arbitrarily large amounts of geographic data. The delivery and persistence model for Scene Layers, referred to as Indexed 3d Scene Layer (I3S) and Scene Layer Package (SLPK) respectively, are specified.
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Features Attributes #54

Closed Shtirlic81 closed 4 years ago

Shtirlic81 commented 4 years ago

Hi,

In features file there is a definition of the geometry structure:

vertex ==> offset, number of elements... normal ==> offset, number of elements...

I don't see the same definition for the features, such as Id and face range, where can I find their offset information?

Thanks

ajuanr commented 4 years ago

If the offset information is not available in the features file, you can examine uncompressed geometry buffer.

The buffer contains an 8-byte header. The first 4 bytes is the vertex count and the next 4 is the feature count. The bytes are in little endian order.

The order of vertex attributes is fixed: position
normal
uv0
uv1
color
uvRegion
featureId
faceRange

All vertex attributes have a fixed size that can be computed as: #component * sizeof( type ) * {#vertices or #features}

Shtirlic81 commented 4 years ago

Why not put this information, and let the user calculate and extrapolate this base on the geometry size?

rvargasESRI commented 4 years ago

@Shtirlic81 Could you clarify a bit more about how this relates to the original issue posted? Thank you.