open-standards/wai/changes/2026-11-09-int-neural-fields.md

Integer neural fields: wai.field.int_grid, a scene the sink computes, refined level by level by wai.field.int_refine

• A computed capability registered (SPEC §5, Interactive, temporal & computed content): wai.field.int_grid, a volumetric scene held as a multi-resolution integer feature grid and a small integer network, StandardDefined at field-equivalence. The sink computes the content: the field's density and colour at any point of its domain, and its frame at any view by integer ray marching. neural-fields fixes every integer: a level's table is read through a direct index where its vertices fit, and through a spatial hash with a stated wrap (each product modulo 2^32) where they do not; the trilinear weights are fixed point at 2^48 and sum exactly; each layer is integer-operators' conv with a 1 × 1 kernel, its rq rounding half up by wfrac bits, a clamp to i32 and relu; the camera is splat-exact §5.3's; the samples, their lengths, the transmittance's stop and the compositing are pinned. So the values at a point and the frame at a view are the same bytes on every machine, and a frame digest can be signed and checked where the frame is presented.
• The payload WIG1 (neural-fields §3): L levels declared and the coarsest K carried, the network's widths and layers, and the view the field is presented at (a pose of splat-exact §2's members, the samples a ray takes between t_near and t_far, and a background). A level not carried reads as zero, so a coarse prefix is a presentable field. Its checks follow integer-payloads §2's order and refuse with that extension's codes, including a network whose input width is not L · F and a degenerate pose (field_range). The emit paths check the framing with the parser a sink runs.
• Levels as refinements (neural-fields §7; SPEC §5, Refinement capabilities and Base admission): wai.field.int_refine, refinement-only over the one base wai.field.int_grid, StandardDefined, its payload WIL1 one grid level of the field. A level applies only as the field's next level, in the features, table size and side the field declared for it, or it is refused (geometry_mismatch) and the field is as it was. staged-delivery §6.2 registers this level form (the former §6.2 and §6.3 are now §6.3 and §6.4): the unit is the whole field, layer k carries level K + k − 1, §4.1 step 9 is the next-level rule, the stage hash is the SHA-256 of the render at the field's own view, the tier is decode-equivalence, and every layer boundary is a truncation point. So a coarse field is presented first and every stage is presentable.
• Reference implementation. wai-rs: int_field (feature field_int): parse_wig1, parse_wil1, Field::{query, render, apply_level}, View, the declared cost, FieldStages (staged-delivery §4.1 for the field's one unit), and int_field::corpus; the float-free test reads int_field.rs. tools/wai_int_field_export.py writes the payload from a JSON form and builds the corpus's scenes itself: one fitted to a procedural scene by stochastic gradient descent on each level's table in turn, through the level's own index and hash, one seeded random, one of saturating values.
• Conformance. volumetric-conformance/fields/: three scenes, the values at 32 points and the frame digest at each scene's own view and at further views, at every prefix of the fitted scene's levels; a fault payload for every check of WIG1 and WIL1, each with its code; levels applied in order, out of order, twice, past the field's levels and in the wrong shape; and envelopes offered as layers in five sequences (in order, out of order, a refusal at each envelope step, a conflict, a level that fails the next-level rule and then conflicts), each with its stage or reason and the final stage hash. Written and checked by wai_int_field_vectors and tests/int_field.rs. field_verify.py parses every payload, applies every level and computes every value, frame and stage hash with its own integer arithmetic, sharing no code with wai-rs. Both plant five faults in their own decode (an interpolation weight off by one, a hash multiplier changed, a layer's rounding flipped to floor, one ray sample too many, a level applied out of order) and require the corpus to catch each.
• Breaking: api:rust:wai::codecs::AppliedForm::Level: the level form is a staged form of its own; a match over AppliedForm adds the arm, and is_refinement_only already counts it.
• Breaking: api:rust:wai::int_field::Plant::ALL: the corpus plants a fifth fault, a level applied out of order; code that iterates Plant::ALL needs no change, code that names its length reads 5.
• Breaking: api:rust:wai::int_field::Plant::LevelOrder: that fault's variant; a match over Plant adds the arm.
• Breaking: api:rust:wai::int_field::corpus::SCENES: each scene now names the levels that refine it; read the first member of each pair for the scene's name.
• Breaking: api:rust:wai::int_field::corpus::Verified::applications: verify counts the level applications it reproduced; a pattern over Verified adds the field or ...
• Breaking: api:rust:wai::int_field::corpus::Verified::offers: verify counts the layers it offered; a pattern over Verified adds the field or ...