Question: Is the light source always located at the Mounting Height (MH) value in the luminaire toolkit?

Answer: No, not always. It depends on the calculation mode being used in AGi32. Consider the following example of a traditional postop luminaire.

In DIRECT calculation mode

The light source is a point source and is located at the MH value set in the toolkit. It has no luminous area. Symbols have no impact.

In this case, the MH value entered by the user should NOT equal the pole height. The MH value should be entered as the height to the center of the luminous Z-dimension of the luminaire.

In FULL RADIOSITY calculation mode

The light source is an area source with a “luminous box” dimensions per the “Luminous Area” values found in the Photometric file (IES, LDT, CIB).

The MH value in the toolkit references the Z-dimension from zero to the render mode symbol Insertion Point: Top or Bottom. Each symbol is different in size and can be scaled in the Render Mode Symbol dialog accessed from the Luminaire Define dialog. Be aware of the physical size of the luminaire. Scale the AGi32 Render Mode symbol to match as closely as possible.

The luminous box is centered in the render mode symbol luminous Z-dimension.

Insertion Point = Bottom

The distance from the insertion point of the symbol to the center of the Z-dimension is added to the MH value effectively placing the luminous area above the pole height as it would be in reality. If the symbol is scaled correctly, the user should enter the pole height in the MH cell.

Insertion Point = Top

The distance from the insertion point of the symbol to the center of the Z-dimension is subtracted from the MH value. This would not be correct for a postop, but more appropriately used for a suspended luminaire.