# Planar IES emitter¶

## Description¶

Planar spot IES emitter. The emitting geometry is a small rectangle in the ceiling

The planar IES emitter uses IES data and extracts the half-sphere equivalent radiance for a planar source. It is suited for IES sources which have no or little light emitted in the back direction.

As IES files contain only luminous intensity information and no spectral data, a base spectrum must be specified. It is then normalized to keep the IES values correct.

The actual lumen output will depend on flux mode:

• In “Per Instance” mode, IES values are mapped to object instances. If a 1000 lumen IES source is applied to two instances of a luminaire geometry, they will emit 1000 lumen each. But if a single geometry models two luminaires, and is instanced once, the luminaires will share the 1000 lumen flux, and will emit 500 lumen each if they are identical.

• In “Per m2” mode, IES values are mapped to every square meter of geometry. If a 1000 lumen IES source is applied to a 0.20m2 geometry, the resulting light output will be 200 lumen.

Note

## Children Nodes¶

 base The base emission spectrum iesdata The IES formatted text data

## Parameters¶

name

type

description

forward

vec3

Orients the IES light source main axis to this direction in tangent space

right

vec3

Rotates the IES light source around its axis to set its right pointing at this direction in tangent space. Should be orthogonal to forward

flux

list

Sets the flux mode (“instance” or “squaremeter”)

multiplier

real

Multiplies all IES values by this factor

## Ocean XML 6.1 example¶

<emitter name="emitter" type="planar_ies" forward="0 -1 0" right="0 0 -1" flux="instance">
<spectrum type="tabulated" name="base">
3e-07  0       4e-07   0       5e-07   1.2e+08 6e-07   2.4e+08 7e-07   2.9e+08
</spectrum>
<text name="iesdata">
[Truncated IES data...]
</text>
</emitter>