Method

The Bake Lighting To Object node bakes static lighting information for objects in the scene into lightmap textures, which are then applied back on to the objects to replace dynamic lighting.

Baking the static lighting of the scene will drastically improve the performance of a Notch scene that uses processing-intensive lights such as skylights, raytraced lighting and shadowed lights. By baking in the static lighting information, those baked light nodes will have no performance cost. These lights can be turned off/hidden (Ctrl 1) once the scene has been baked.

Setting up the scene

Building a Notch scene for light baking is no different from setting up any other Notch scene. The only additional task that is required is to create a secondary UV channel with non-overlapping unique UVs for any meshes that you want to statically bake.

To set up the baked lighting scene, firstly add a Bake Lighting To Object node to the node graph and connect the 3D mesh that you want to bake into the top of this node. A Bake Lighting To Object node will be required for each object to be baked.

There is an input tab on the bottom of the Bake Lighting To Object node, this is used to attach the lights that you want to bake in the scene. If any real-time animated lights are required in the scene, these lights should not be connected to the Bake Lighting To Object node.

Once you have connected the Bake Lighting To Object nodes to the objects you can start the baking process.

Step 1

Select the Bake Lighting To Object node, set the width and the height of the lightmap that you want to produce.
Smaller objects should have lower resolution lightmaps and larger objects higher resolution lightmaps.

Step 2

To remove the noise from the lightmap there is a “Post Filter Lightmap” checkbox, this will add a smart blur to the lightmaps making them less noisy. Turn this on before baking the lightmaps.

Select the UV channel that you have set up your unique UV set on. Traditionally Colour UVs are your original UV setup and they are your primary UV layout. It is always best to set up a secondary UV set “Diffuse UV (Lightmap) set on the 2nd UV channel, in this way you can setup up a unique UV’s set on your 3D model without impacting the original UV set.

The UV channel on the 3D mesh will also need to be set. In the properties for the 3D object – UV Sets – Diffuse Texture UV Set – needs to be set to the UV channel you want the lightmap to use.

Step 3

Hit the Bake Now.. button, this will open the bake properties dialogue box.
Set the number of refinement passes that you want on the lightmap the more set the higher the build time and the more refined the lightmap texture. 10 refinements is a good way to preview the lightmap, 500 refinements will take longer but the lightmap will be better quality.

Step 4

Turn off any baked lights, drastically improving performance as they no longer need to be calculated in real-time.
Turn back on any animated lights that you want to keep real-time.

Example Nodegraph before bake
Example Nodegraph after bake

Baked raytraced sky lighting in an exterior location.

Baked Skylight Exterior

Baked spotlights and raytraced skylight as well as a real-time spotlight.

Baked Spotlights

Bake Lighting To Object

Name Description
Bake Now Opens the “Bake Properties” dialogue box.
Show Rendered Texture Displays the rendered lightmap texture in the viewport.
Width Sets the width of the lightmap texture.
Height Sets the height of the lightmap texture.
Bit Depth Sets the bit depth of the texture, 16bit is HDR.
Post Filter Lightmap Toggles on and off a smart blur on the lightmap. In order to work, this has to be ticked on before the bake is set off.
Disable Baking (Pass Through) Hides the lightmap on an object so the lighting is visible.
UV Channel Sets the UV channel that the lightmap texture uses.
Colour Default UV channel
Diffuse (Lightmap) UV channel 2
Colour – Original UV’s UV channel 1
Baked Lightmap Automatic name of the baked lightmap

Bake Properties

Name Description
Preset Use custom preset values to generate lightmap.
Export Type This is set to a default texture type.
Filename Sets filename and location of the lightmap texture.
Refinement passes This sets the number of refinement passes on each texture, the higher the number of passes the better the fidelity of the lightmap texture (set between 10 Quick pass – 500 high quality)

Outputs

There are no outputs from this node.