Emitter

Thea Render supports both area and point light emitters. The area emitters are applied to a surface. Typically, the area emitter has a diffusion-like emission model and distributes light evenly in all directions. Nevertheless, more complex emission models can be defined using an IES file.

Color: You can define the color of the light using the following options: Color, Custom Color, Temperature, Bitmap, and Procedural.
Power: Define the power of the emittance.
Passive Emitter: The emitter will not cast light into the scene, but it will glow.

IES Emitter

To convert a standard emitter to an IES emitter, click the hamburger menu icon and select IES Emitter.
Efficacy: Maximum efficacy is 683 lm/w, which corresponds to light with no energy loss (all power is converted to visible light).

Custom Evaluations
Custom Light Evaluation allows the user to select which components (such as Diffuse, Translucent, Reflectance, Transmittance, and SSS) will be evaluated for a given light, thus removing unwanted contributions and accelerating render times.

In the following example we are making use of Custom Light Evaluation for the emitter.

Enabled	Disabled
		Diffuse: Every material using a diffuse component (most visible on the floor surface) will not be affected by the emitter.
		Translucent: Translucency of the sphere in the middle is not affected by the emitter.
		Reflectance: Every surface with reflectance (floor, glass and plastic sphere) will not be affected by the emitter. The emitter itself will not be visible in the reflections.
		Transmittance: The glass sphere will not be affected by the emitter. The emitter itself will not appear in the refraction of the object and light will not pass through the object.
		Medium and SSS: The medium component of the sphere to the right is not affected by the emitter.