SketchUp FAQ - Lighting

Environmental Lighting

This type of lighting, which contributes globally to lighting the rendered image, may use one of four types: Sky Dome, Physical Sky, Image Based, and None. Environmental lighting is set up in the plugin using the Environment tab in the plugin's Scene Manager window.

Physical Lighting

This type of lighting is concerned with the creation and use of individual emitters; in Maxwell, emitters consist of geometry which has been assigned an emitter material. The basic steps involved in creating an example rectangular light, then, are these:

1. Draw a plane.
2. Select a material, as described here.
3. Set the material to use an emitter Character type.
4. Assign this material to the plane.
5. Render the scene.

The geometry determines the physical position and directionality of the light, while the emitter material determines the nature of the light that is emitted from that geometry. Besides for these creation steps, there are two main factors to consider:

Surface Normals

In Maxwell, light is emitted according to the normals of the mesh in question. In SketchUp, the normals point in the direction of a face's front material, so use SketchUp's right-click > Reverse Faces command if necessary. Since this alters the geometry physically, it is necessary to use the Re-export Scene function in Maxwell Fire, before changes will be reflected in the rendering.

Emitter Power

Since Maxwell is physically correct, it is necessary to ensure that you provide it with realistic model. This includes both the overall scale of the scene, and the values given to the power-related parameters of emitter materials. Since the output of an emitter is spread across the surface of the mesh to which it is assigned, modeling at too-large or too-small of a scale will result in lights which shine too weakly or too strongly.

IES Emitters

In Maxwell, IES files are used by creating an IES emitter material which references an IES file, and applying that material to geometry. In the SketchUp plugin, the steps for accomplishing this are as follows:

1. Create a new material (in SketchUp's materials window).
2. Open the Scene Manager and go to the Materials tab.
3. Select the newly-created material from the drop-down list.
4. Switch the material's Character to IES Emitter.
5. Browse to select the desired IES file.

It will be best, when rendering a material preview for this new material, to switch Preview > Scene to the ies_emitter scene, which is set up for previewing IES files. With the material created, the next step is to apply it to geometry: create a small sphere, group it, and apply the new IES material to the group. The reason for using a group is so that there can be a direction for the light to shine; the transformation of the group is used to define the direction of the light.