Baked vs Realtime Lighting on Quest

On Quest, baked lighting is usually the practical choice. Baked lights are calculated ahead of time and stored in lightmaps and textures, so the headset does very little lighting work while you play. Realtime lights and shadows cost far more on a mobile chip that has to draw every frame twice, once for each eye, so the usual approach is to bake most of the room and spend your small realtime budget on the few lights that matter.

The rest of this guide explains why that cost adds up, how to mix a few dynamic lights into a baked scene, and which shadow tricks give you the most visual value for the least cost.

Why is baked lighting the usual choice on Quest?

Every light in a scene adds work for the GPU. A realtime light has to be calculated for every pixel it touches, and if it casts shadows, the engine must also render the scene from the light's point of view. Quest runs on a mobile chip with a tight power and heat budget, and VR doubles most of that work because each eye gets its own image.

Baked lighting moves that work out of the frame. The lighting is computed in the editor, saved into lightmaps, and the headset only reads the result. You get soft bounced light, believable corners and shadows that cost nothing extra per frame. The trade-off is that baked light cannot move, so it is a poor fit for a swinging door or a flickering lamp.

What baked lighting does well

• Soft indirect light in corners, under tables and along ceilings
• Static shadows from walls, pillars and furniture
• Low runtime cost, which leaves room for enemies, particles and effects
• Predictable frame times across a long level

Where baked lighting falls short

• Anything that moves or changes state, such as doors, lamps and fires
• Light that has to react to the player's flashlight
• Large lightmap textures, which add to memory use on the headset

How do you mix in a few dynamic lights?

The trick is to decide which lights earn a realtime slot. A dynamic light should exist because the moment depends on it: a flashlight the player controls, a warning light during an alarm, or a single lamp that swings. Lights that only make a corner look nicer should stay baked.

1. Bake the room first. Use baked or mixed lighting for walls, floors and ceilings so the base look is cheap and consistent.
2. Pick one to three realtime lights per room, and give each one a gameplay or story job.
3. Keep each dynamic light's range tight. A light that reaches a short distance and stops costs less and is easier to control than one that floods the whole room.
4. Allow only one dynamic shadow caster per area. If two lights need shadows, bake one of them.
5. Use light probes for moving objects. Probes store baked light at points in the room, so a moving enemy or a crate picks up believable light without a light of its own.
6. Test on the headset. The editor preview is misleading on mobile hardware, so check frame times on the device after every lighting change.

Engine names differ, but the ideas carry over. Unity calls this approach Mixed lighting, and Unreal uses Stationary lights for something similar. In both cases you get a baked base with a realtime layer on top.

Which shadow tricks work best on Quest?

Shadows are where most of the cost hides, so the cheap versions matter. This table runs roughly from cheapest to most expensive.

Technique	Runtime cost	Best for	Watch out for
Baked shadows	Almost none	Walls, floors, furniture and anything that never moves	They cannot react to moving objects
Blob shadows	Very low	Characters, crates and props that move across the floor	They look flat on slopes and stairs
Projected light textures	Low	Window light, lamp patterns and cage shadows	Needs an extra texture and careful placement
Shadow proxies	Low to medium	Moving objects that need a silhouette on walls	Simple meshes must still match the look
Realtime shadows from one light	High	A single important moving shadow, such as a flashlight	Keep shadow distance and resolution small

Blob shadows deserve a closer look. A flat, soft dark shape under an object costs almost nothing and reads well at VR distance, which is why so many VR games use them for characters. Pair them with small contact shadows under table legs and boxes, because those small details do most of the work in selling the weight of an object.

Shadow distance is the other quiet cost. Shadows that reach across a large room cost more than the player can use, and the player is usually looking at nearby details anyway. Pull the distance in, then check that the edges of the shadows still look clean from the spot where players usually stand.

What mistakes make a Quest scene slow?

• Baking everything and then adding realtime lights on top, which doubles the work
• Testing only in the editor, where the hardware is far stronger than the headset
• Leaving every light's shadow and range at the default
• Using full-resolution lightmaps on surfaces the player never looks at closely
• Forgetting that stereo rendering doubles the cost of each light

For more on how art choices change the cost, see stylized vs realistic art for VR performance. Lighting also sets the mood, so lighting and darkness in horror games is worth a read if your level is meant to frighten. If you are bringing a PC game across, porting a PC VR game to Quest covers the other budget changes you will need to make.

Start with a fully baked room, then add realtime lights only where they change what the player does or feels. Check frame times on the headset, not in the editor, and keep one realtime shadow per area. Done that way, the room looks grounded and the headset stays comfortable to render.