{"schema":"record/v1","id":"art_01M5MDXVFZHG1R9PT5B59BJWN3","type":"article","revision":1,"etag":"\"r1.s0\"","title":"In an OpenEXR handed to compositing, how are layers, parts and channel names defined, and what does Blender's writer do when it writes single-part layers versus multipart?","summary":"OpenEXR names layered channels L.C (nestable) without any stacking or compositing meaning; multipart parts need unique names (dots allowed) and may differ in compression and data window and mix deep and flat. Blender v5.2.2 writes either single-part channels layerpass.view.C or, in multipart mode, one part named layerpass-view with channels layerpass.C.","status":"active","body":{"text":"OpenEXR names layered channels L.C (nestable) without any stacking or compositing meaning; multipart parts need unique names (dots allowed) and may differ in compression and data window and mix deep and flat. Blender v5.2.2 writes either single-part channels layerpass.view.C or, in multipart mode, one part named layerpass-view with channels layerpass.C.\n\nCurator qualifications: Code and docs read 2026-10-22; nothing rendered or written. exrmultipart tool page (S29) not re-read.\n\nLimitations: Code and docs read 2026-10-22; nothing rendered or written.\n\nEvidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.","citations":[{"url":"https://github.com/AcademySoftwareFoundation/openexr/blob/69b2604fc76e370615438bdc8d2cd95b9349c12e/website/TechnicalIntroduction.rst","note":"OpenEXR website/TechnicalIntroduction.rst at 69b2604f (raw), Channel Names; multi-part header attributes; blender imbuf/intern/openexr/openexr_api.cpp at d13f752e (raw), IMB_exr_add_channels"},{"url":"https://github.com/AcademySoftwareFoundation/openexr/blob/69b2604fc76e370615438bdc8d2cd95b9349c12e/website/bin/exrmultipart.rst","note":"OpenEXR website/TechnicalIntroduction.rst at 69b2604f (raw), Channel Names; multi-part header attributes; blender imbuf/intern/openexr/openexr_api.cpp at d13f752e (raw), IMB_exr_add_channels"},{"url":"https://github.com/blender/blender/blob/d13f752e3b9c4f8c261cda552b1021f8bcc0382c/source/blender/imbuf/intern/openexr/openexr_api.cpp","note":"OpenEXR website/TechnicalIntroduction.rst at 69b2604f (raw), Channel Names; multi-part header attributes; blender imbuf/intern/openexr/openexr_api.cpp at d13f752e (raw), IMB_exr_add_channels"}]},"categories":["T11","T15"],"tags":[],"language":"en","visibility":"public","moderation":{"state":"visible","reason":null},"evidence":{"inspection":"source_inspected","execution":"not_run","review":"unreviewed","review_revision":null,"claims":[{"url":"https://github.com/AcademySoftwareFoundation/openexr/blob/69b2604fc76e370615438bdc8d2cd95b9349c12e/website/TechnicalIntroduction.rst","claim":"OpenEXR names layered channels L.C (nestable) without any stacking or compositing meaning; multipart parts need unique names (dots allowed) and may differ in compression and data window and mix deep and flat. 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Blender v5.2.2 writes either single-part channels layerpass.view.C or, in multipart mode, one part named layerpass-view with channels layerpass.C.\n\nCurator qualifications: Code and docs read 2026-10-22; nothing rendered or written. exrmultipart tool page (S29) not re-read.\n\nLimitations: Code and docs read 2026-10-22; nothing rendered or written.\n\nEvidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.","citations":[{"url":"https://github.com/AcademySoftwareFoundation/openexr/blob/69b2604fc76e370615438bdc8d2cd95b9349c12e/website/TechnicalIntroduction.rst","note":"OpenEXR website/TechnicalIntroduction.rst at 69b2604f (raw), Channel Names; multi-part header attributes; blender imbuf/intern/openexr/openexr_api.cpp at d13f752e (raw), IMB_exr_add_channels"},{"url":"https://github.com/AcademySoftwareFoundation/openexr/blob/69b2604fc76e370615438bdc8d2cd95b9349c12e/website/bin/exrmultipart.rst","note":"OpenEXR website/TechnicalIntroduction.rst at 69b2604f (raw), Channel Names; multi-part header attributes; blender imbuf/intern/openexr/openexr_api.cpp at d13f752e (raw), IMB_exr_add_channels"},{"url":"https://github.com/blender/blender/blob/d13f752e3b9c4f8c261cda552b1021f8bcc0382c/source/blender/imbuf/intern/openexr/openexr_api.cpp","note":"OpenEXR website/TechnicalIntroduction.rst at 69b2604f (raw), Channel Names; multi-part header attributes; blender imbuf/intern/openexr/openexr_api.cpp at d13f752e (raw), IMB_exr_add_channels"}]},"tags":[],"type":"article","links":[],"title":"In an OpenEXR handed to compositing, how are layers, parts and channel names defined, and what does Blender's writer do when it writes single-part layers versus multipart?","rights":[{"notes":"Applies to this original summary only, not to the cited sources.","hosting":"permitted","component":"documentation","license_id":null,"modification":"unknown","evidence_urls":[],"model_training":"unknown","redistribution":"permitted"}],"summary":"OpenEXR names layered channels L.C (nestable) without any stacking or compositing meaning; multipart parts need unique names (dots allowed) and may differ in compression and data window and mix deep and flat. 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