Reference

Quality levels

Four tiers, from integrated laptop GPUs to 4K desktops. Every field is overridable at runtime.

const sky = await SkySystem.create({ renderer, scene, camera, quality: 'medium' });
sky.setQualityLevel('ultra');
sky.setQualityLevel('high', { marchScale: 0.66, raySteps: 16 });   // tier + overrides
sky.qualitySettings;   // the effective settings

#At a glance

Tier	Cloud march res	March / light steps	Shadow map	Env map · PMREM cube	Env refresh	God rays	Bloom / MSAA
`low`	1/3	32 / 4	256² @ 2 Hz	128×64 · 32	1 Hz	off	off / 0
`medium`	1/2	44 / 5	256² @ 5 Hz	256×128 · 64	2 Hz (2 slices)	8 steps	on / 2
`high`	1/2	56 / 5	512² @ 10 Hz	512×256 · 128	4 Hz (4 slices)	12 steps	on / 4
`ultra`	3/4	80 / 6	1024² @ 20 Hz	1024×512 · 256	8 Hz (4 slices)	16 steps	on / 4

Resolutions are relative to the drawing buffer. The env bake is spread over "slices" frames so it never spikes.

#Every field

Field	low	medium	high	ultra
`marchScale`	0.34	0.5	0.5	0.75	Cloud march res / drawing buffer
`historyScale`	0.5	0.75	1	1	TAA history res / drawing buffer
`marchSteps`	32	44	56	80	Primary march budget
`lightSteps`	4	5	5	6	Self-shadow steps per sample
`shadowSize`	256	256	512	1024	Shadow map texels per side
`shadowSteps`	8	10	12	16	March steps per shadow texel
`shadowInterval`	0.5	0.2	0.1	0.05	Seconds between shadow bakes (dynamic)
`envSize`	128	256	512	1024	Equirect width (PMREM cube = width / 4)
`envSteps`	16	24	32	48	Cloud steps in the env bake
`envInterval`	1.0	0.5	0.25	0.12	Seconds between env + PMREM refreshes (dynamic)
`envSlices`	1	2	4	4	Frames one env bake is spread over
`pmremSamples`	32	48	64	128	GGX samples per texel (three.js default 256)
`godRays`	off	on	on	on	Post-pass god rays
`raySteps`	0	8	12	16	God-ray / fog march steps
`bloom`	off	on	on	on	Post-pass bloom + shafts
`msaa`	0	2	4	4	Post-pass scene target samples

#Pick a starting tier

Target	Tier
Integrated GPUs, phones, 4K at pixel ratio 2	`low`
Mid-range laptops	`medium`
Apple M-series, discrete desktop GPUs at 1080p–1440p	`high`
Stills, trailers, 4K posters	`ultra`