blendertk v0.5.39

• 2026-07-29 — Scene-data sidecar (mirrors mayatk's rename, plus the exporter-side write Blender never had). HierarchySidecar → SceneDataSidecar (scene_data_sidecar.py, registered as btk.SceneDataSidecar; old module = import shim): the manifest is now format v2 — hierarchy diff baseline + data_export channel snapshot in one .{stem}.scene_data.json, with read_data() and the migrate_legacy() promotion of v1-named sidecars (mayatk's changelog has the full design rationale). New here: the SceneExporter actually writes the sidecar post-export. mayatk maintained its manifest via the hierarchy check's task-manager hook, but blendertk's exporter had no sidecar wiring at all — the check is still a disabled placeholder (TODO(blender-parity), tooltip updated to say precisely that). The write lives on the engine (_write_scene_data_sidecar, same reason as _create_glb: blendertk's TaskManager carries no export_path), is gated on the carrier having actually shipped (present in the export set — a hidden carrier excluded from a selected-mode export records nothing) or an existing manifest to maintain, and is best-effort — the record can never break the export it records. The engine's native _VERSION_SUFFIX_RE re-implementation (its comment claimed the sidecar class "lives in the unported hierarchy_sync subsystem" — stale since the sidecar port) is deleted in favor of SceneDataSidecar.VERSION_SUFFIX_RE. test_scene_data_sidecar.py (was test_hierarchy_sidecar.py) 43/43 headless, incl. v2-format / v1-compat / name-migration checks.

• 2026-07-29 — Scene Exporter's missing-file check no longer fails an export over textures that never ship (mirrors mayatk). check_valid_paths walked every FILE image datablock in the .blend — its docstring even called the whole-file scope deliberate, "matching Maya's version". The Maya version turned out to be the bug (see mayatk's entry: an HDR environment map and orphaned duplicate-material file nodes flooded a real export log), so both sides move to the export scope. Image scope is now _get_export_images() — the datablocks feeding the materials assigned to self.objects — which drops the World/Environment-Texture HDR and the zero-user images a duplicate-material cleanup leaves behind. Linked libraries stay whole-file: they are the analogue of Maya's scene references, not of a texture. The scoping is applied by filtering MatUtils.get_image_records() against the export set rather than re-deriving "is a FILE image whose abspath exists" locally — that predicate belongs to get_image_records, and a second copy of it in the check would be free to drift. test_scene_exporter.py +2 (an unassigned broken image is ignored; a missing texture on an export material still fails).

• 2026-07-29 — The "blendertk panels get a hide button" rule is now a default the UI Browser can override (mirrors mayatk). BlenderUiHandler.apply_styles hardcoded style["header_buttons"] = ("menu","collapse","hide") for anything tagged blendertk — a fixed tuple no user preference could outrank, and one of the three reasons the UI Browser's window-persistence setting had no effect (uitk's changelog has the diagnosis). Replaced by uitk's new default_persistence(ui) hook: blendertk-tagged UIs declare PERSISTENCE_STICKY, everything else falls through to the base PERSISTENCE_TRANSIENT — identical defaults, now at the bottom of a precedence chain the browser's global setting and per-window "Open as" override sit above. The gesture-scoped panels that ask for a pin button in header_init are unaffected (the handler leaves a self-configured header alone unless there's an explicit choice, and then swaps only pin/hide). test_blender_ui_handler.py +3 (default is sticky, an override outranks it, apply_styles is no longer overridden). Also fixed a stale assertion in that suite (pre-existing, unrelated): it pinned UnityBridgeSlots.MODE_LABELS to the single {copy: "Copy to Project"} entry from before the panel-native "Manage Unity Scripts" mode shipped — the mayatk twin carries the same two modes, so parity holds and the test, not the code, was wrong; it now asserts both modes plus the still-retired Unity Studio / existing-project ones. Suite back to 226/226.

• 2026-07-29 — 25 panels declared fixed-vertical (mirrors mayatk): no more stretching into dead space above the footer. Same sweep and same classification as the mayatk entry — a panel is locked only when its trailing spacer is the sole vertical absorber. Those panels' spacers are now sizeType=Fixed with each group box declaring vsizetype="Fixed", making Qt's own QLayout.maximumSize() finite rather than leaning on uitk's container see-through; seven untuned Qt Designer 20x40 spacers are tuned to the 10px norm (a Fixed spacer's hint is its exact, unresizable height). Panels with real growable content stay resizable. Parity with mayatk is preserved panel-for-panel; verified through the real loader (finite native cap, ~10px footer gap, exact collapse/expand round-trips).

• 2026-07-29 — Shell Xform gains Gather to Tile, and its snap now respects the tile border padding (parity with mayatk). UvUtils.gather_to_udim mirrors the Maya twin: stray islands return to the target UDIM by whole-tile offsets that keep their sub-tile position, clamped inside the shared border margin, with the target decided by majority vote when no UDIM is given. Islands are resolved in two passes (vote, then apply) because the object-mode bmesh is freed when the edit callback returns, so island references must not escape it. The vote pass runs only when no UDIM is given, and the vote itself is ptk.MathUtils.majority_tile. The move pad's grid snap lands islands one margin inside each grid line instead of on it. _island_bounds factored out of _island_bbox_center backs both. A partial selection moves the whole island — free here via _target_islands, and now asserted, because the Maya twin had to be fixed to match.