UCS reads its base-UCS handle inline and skips OrthographicType on R2000-R2004 (§20.4.62) #285

Spec: §20.4.62 UCS (63), p170-171. R2000+ data fields after the Y-direction: Elevation BD 146, OrthographicViewType BS 79, OrthographicType BS 71. Handle refs: the UCS control object, then R2000+ Base UCS Handle H 346 and Named UCS Handle H, all after the data fields.

Finding (read from the spec, unmeasured)

On R2000 and R2004, tables::ucs::decode reads Elevation and OrthographicViewType, then reads the base-UCS handle inline, as the next data-stream field, and never reads OrthographicType. On every pre-R2007 release the handle refs follow the record's RL data boundary, so an inline handle read cannot land on it (the rule #63 applied to the entity decoders). The R2007+ split-stream path also omits OrthographicType.

No corpus drawing holds a UCS record, and the spec's only UCS example (§20.4.62.1) is an R13/R14 record (#274), so neither reading has been measured. The closes state of §20.4.62 in docs/spec-coverage.md rests on no record.

Acceptance

• The R2000/R2004 data fields are BD, BS, BS, with no inline handle, unless a measured record says otherwise.
• A UCS record on R2000+ is measured (an authored drawing, blocked:sample until one exists), and §20.4.62's state is set from it.