solvecraft/docs/render-settings.md

Persistent render settings

Named setups save common render settings and, optionally, the complete numerical configuration of one selected image method, including an optional embedded HDR. Saving does not start a render, apply the navigation camera or require an installed CPU/GPU executor. render.preflight and render.start consume the same saved configuration and still check the current host, geometry, capabilities and memory limits.

Commands

{"command":"render.settings.set","params":{"name":"Studio","set":{"width":1600,"height":900,"exposure_ev":1.5}}}
{"command":"render.settings.get","params":{"name":"Studio"}}
{"command":"render.settings.get","params":{}}

set creates a named setup from defaults or replaces supplied top-level fields in an existing setup. A supplied camera or job replaces the whole value; it is not a recursive patch. Omitted fields retain their values. job: null explicitly clears the job and restores the legacy request protocol. Unknown fields (including camera/job fields), invalid types and invalid values fail before document mutation. A new empty set saves the defaults; setting an existing setup to identical values is a no-op, preserving redo history and revision. Each effective edit is one undo step and marks the document dirty. There is no delete or rename command in this slice.

Named get returns {name, setup} or an error for a missing name. Without a name, it returns {setups, defaults}. Reads do not evaluate the model or change history.

Field	Default	Saved contract
backend	builtin	Valid R1 backend ID, at most 64 ASCII bytes; unavailable IDs survive reopen
mode	preview	R1 preview / final mode; availability checked by a future render request
camera	Existing Camera::default()	Snapshot of target, yaw, pitch, roll, distance, fov and up; mm/radians, existing Z-up default
width, height	1024, 768	Positive, each at most 4096; product at most 4,194,304 pixels
format	png	R1 output format (png / exr); saving EXR does not add an encoder
exposure_ev	0	One exposure authority: raster requires 0; CPU raytrace accepts -16 through 16; GPU path accepts -32 through 32. Legacy setups retain -32 through 32.
environment_rotation	0	Legacy finite radians, magnitude at most 1,000,000. A typed job requires 0.
environment_intensity	1	Legacy finite value, 0 through 100. A typed job requires 1.
background	[236, 240, 245]	Three sRGB byte values; display backplate, independent of illumination
job	absent	Optional typed active raster, cpu_raytrace or gpu_path configuration; absent/null keeps the legacy protocol

Camera target coordinates and positive distance are bounded to magnitude 1e9 mm; angles to 1e6 radians. FOV is finite, 0 <= fov < pi; zero means orthographic in the existing camera model. Both existing camera up axes are retained. Setup names are trimmed, nonempty, at most 128 UTF-8 bytes, without control characters. A document has at most 32 setups. Validation also runs during document deserialization.

Complete numerical job intent

job is tagged by method. It saves the active method, rather than separate CPU and GPU drafts. All numbers use the existing renderer contracts: world distances are millimetres, angles are radians and light colours/radiances are linear RGB.

Method	Saved fields	Main limits and defaults
raster	transparent_background	Defaults to false; no nonzero exposure or raytrace controls
cpu_raytrace	options: optional progressive, primary_samples, preset, lights, punctual_lights, area_lights, area_samples, seed, shadows, constant environment, embedded hdr	Primary samples 1/4/16 (default 1); shadows true; optional progressive/lists/preset/environment/HDR absent. At most 8 directional, 8 point/spot and 4 rectangular lights; progressive has the narrower contract below.
gpu_path	transparent_background, options: samples, max_depth, seed, tone_map, denoise, lens, lighting, sky environment, embedded hdr	Samples 1..4096 (default 64), depth 1..16 (default 8), seed u32 (default 0), Reinhard tone map, denoise false, optional values absent

CPU preset and explicit lights are mutually exclusive. An omitted/null light list remains unspecified; lights: [] explicitly removes the default directional lights. Point lights retain their optional spot cone, its world emission axis and both half angles. Rectangular lights retain full side vectors, sample count and seed; area_samples and seed require a nonempty rectangular-light list. Area samples are 1/4/16/64. Lists are bounded while deserializing and are never truncated. The CPU constant environment retains {color, intensity} independently of the backplate. See CPU light union for the spatial and light validation contracts.

CPU progressive: {samples_per_pixel, seed} stores bounded camera accumulation using the existing CPU transport. An absent/null value preserves fixed AA; an empty object defaults to 16 samples and seed 0. Samples are 1..64 and the seed is u32. primary_samples must be 1, output is at most 1,048,576 pixels, and width × height × samples_per_pixel is at most 16,777,216. Saving checks these limits without a render host. Area/LED lights, dielectric and anisotropic-face overrides are refused in this mode; the fixed CPU route retains them. Embedded HDR and one setup exposure remain compatible. See CPU progressive sampling for reflection limits, work admission and provisional/final publication. The top-level runtime progressive: true continues to select GPU.

GPU lighting retains the complete RGB ambient radiance, optional sun and at most four rectangular lights. Omitted/null lighting keeps the renderer's legacy studio; an explicit all-zero lighting object means a black studio. Those values are not interchangeable. lens retains aperture radius and axial focus distance; nonzero aperture requires a perspective camera. An explicit zero-aperture lens remains explicit. Tone mapping and denoising retain their existing meanings and do not create new executor capabilities.

The portable procedural GPU environment is:

{"kind":"sky","gradient":{"zenith":[0.16,0.32,0.7],"horizon":[0.8,0.9,1],"ground":[0.12,0.1,0.08]},"rotation_rad":0,"intensity":1}

Gradient entries are finite linear RGB in 0..1,000,000; rotation is finite within ±1,000,000 radians; intensity is 0..100. Omitted gradient/rotation/intensity use the shown defaults. The original procedural gradient is not a calibrated atmosphere. An environment replaces the constant ambient-light term; it does not replace the display background. See environment rendering, thin lens and studio lighting.

An embedded HDR uses the separate options.hdr field and cannot coexist with a constant CPU environment or a GPU sky. It references immutable bytes in render.resources, not a file name. Saved HDR resources documents atomic file capture, CPU/GPU colour policies, strict container hydration and the offline save/reopen contract. Optional hdr absent/null means no HDR; when an HDR object is supplied, its resource and controls are required.

RenderSetup.exposure_ev is the only saved EV. CPU lowering copies it into the runtime raytrace.exposure_ev and resets the legacy common-settings EV to zero; GPU lowering uses it in JobOptions. CPU/GPU options.exposure_ev is rejected. The two legacy common environment fields must stay at 0/1 when job is present; the method's typed environment owns those values. Existing legacy values are preserved, and a conflicting conversion fails instead of clearing them.

Save, check and start

{"command":"render.settings.set","params":{"name":"CPU studio","set":{"width":1600,"height":900,"exposure_ev":1,"job":{"method":"cpu_raytrace","options":{"primary_samples":4,"preset":"warm_cool","shadows":true}}}}}
{"command":"render.preflight","params":{"setup":"CPU studio"}}
{"command":"render.start","params":{"setup":"CPU studio","replace":true}}
{"command":"render.settings.set","params":{"name":"GPU studio","set":{"width":1600,"height":900,"exposure_ev":0.5,"job":{"method":"gpu_path","options":{"samples":256,"max_depth":8,"seed":42,"tone_map":"aces_fitted","lighting":{"environment":[0.1,0.2,0.3],"area_lights":[]},"environment":{"kind":"sky","intensity":0.5}}}}}}
{"command":"render.preflight","params":{"setup":"GPU studio"}}

An inline {"settings": full_setup} has the same semantics as a saved setup name. The engine resolves the typed job before choosing CPU or GPU dispatch. A saved gpu_path method requires the gpu-path executor; another executor announcing progressive sampling cannot replace it. A missing or unsupported host blocks Check/Start while leaving the saved intent intact.

For a complete job, the only additional request field is replace. Parallel runtime controls such as progressive, integrator, raytrace, lens, environment or transparent_background fail, including explicit null/false values. They cannot silently override a setup. For legacy job absent/null, the existing runtime request API remains available; it has no inferred CPU/GPU method.

Explicit portability boundary

External HDR paths, texture maps, GPU dielectric/clear-coat/texture body bindings and CPU reflection, anisotropy, emission, surface-effect and dielectric bindings are not part of this saved job format. Their fields are rejected, even when an unsupported list is empty. Runtime requests can still use those existing features with an inline setup whose job is null. Saving a complete setup must not discard them or turn a current body name/ordinal into a persistent identity. HDR bytes are portable through render.settings.capture_hdr; portable maps and durable body/face bindings still require separate contracts. Runtime requests can reference an existing HDR resource while supplying temporary bindings, without persisting those bindings.

No captured scene revision, worker, device, image result, JobId, host availability or external path is serialized. Reproducible input configuration does not promise bit-identical pixels across devices or renderer versions.

Persistence and evaluation

Named setups live in render: {setups: {name: setup}, resources?: {sha256: resource}}; empty render state is omitted. The optional numerical job adds the render-job-intent pending format descriptor. Embedded HDR adds its own render-hdr-resources descriptor. The optional CPU sampling field adds render-cpu-progressive. No historical format number or migration step is rewritten. Older designs need no job transformation: an absent job keeps their common settings and runtime API. Pending builds without the descriptor refuse the newer design instead of silently losing its saved options. Plain JSON, design containers and document autosave snapshots carry all HDR bytes. A command-only crash replay before a new checkpoint still needs the source path recorded by capture_hdr; it must match the recorded digest. This unit does not make that journal self-contained.

The engine avoids geometry evaluation only after proving that the document differs solely in validated render settings, with unchanged active sketch and pending moves. The proof compares the complete document after normalizing the render field, so mixed geometry/appearance/placement edits take the usual conservative refresh path. It uses a document clone/comparison, not a constant-time or whole-application speedup claim. Unchanged render pointers short-circuit the check for normal modelling commands.

Render-only edits, undo/redo and checkpoint restore preserve model state, its stale marker, cached tessellation and the prepared world state. A stale live-drag result never becomes authoritative through a settings edit; the next model-reading command still settles it normally. Revision advances for consumers that track document changes. Geometry, physical materials and appearances retain their existing representations; the setup stores image configuration, not material assignments.

No new third-party dependency or asset is introduced. doc depends on the existing pure render crate for its shared camera and R1 identifiers, within the L2 → L1 rule.