Certain IES Photometric light files do not load or produce "flipped" rendering results in 3ds Max

Autodesk Support

May 28, 2024

Products and versions covered

Issue:

When loading certain IES files into 3ds Max Photometric lights they do not appear in the Web Distribution Display Area and will not load properly.
IES file may load properly, but when rendered produce light patterns that are rotated 180 degrees or flipped.
Rotating an IES light around the Z-axis in the viewport may show the light pattern correctly in a shaded view, but when rendered, the light is flipped around the Z-axis.

Causes:

The extension "IES" stands for Illuminating Engineering Society, and refers to a unit of light measurement and its effect across different surfaces. (For more information, see this CG Arena page.)
Many IES files originate from various lighting manufacturers, some of whom put extra text at the beginning of their IES files. This extra text may cause the IES file to be incompatible with 3ds Max's Photometric lights, or produce incorrect results when rendering.

Solution:

If experiencing difficulties loading or rendering a particular IES file, try the following:

Check the IES file format

The file may need to be edited manually in a text editor. To do this:

Open the IES file in Windows Notepad and check the topmost text in the file. The file should typically start with:

TILT=NONE

If there is text before that (or extra spaces after the TILT=NONE line), then the file may not load, or may produce incorrect rendering results. To fix this issue:

In Windows Notepad, select and then delete all text above TILT=NONE.
Next, check for extra spaces after the TILT=NONE line. If extra spaces exist, delete them.
Re-save the file, then try loading it back into 3ds Max.

The resulting file should look like the following:

Rotate the IES pattern in the Command Panel, not the viewport

Certain IES files may display the light pattern correctly in a Shaded viewport, but when rendered, the light is "flipped" around the Z-axis. This can happen if the light is selected and rotated manually about the Z-axis in the viewport.

To prevent this from happening, do the following:

Select the light, then go to the Command Panel > Modify tab.
Under the Distribution Photometric Web entry, use the XYZ Rotation tools to rotate the light and its pattern in a Shaded viewport.

Free IES Files

For a free source of IES files, go to this online library, which contains more than 300,000 files.

Note: after downloading the files, follow the preceding steps to check if they need manual editing before using in 3ds Max lights.

Use IES lights with the Arnold render engine in 3ds Max

Create an Arnold Photometric light:

Load the IES file in the light creation dialogue at Shape > File.
Place the light in the viewport.

Note: Since Arnold is a physically correct renderer, the look of the light source is interacting with the objects in the scene in a more realistic way.

Products:

3ds Max;

Was this information helpful?

Need help? Ask the Autodesk Assistant!

The Assistant can help you find answers or contact an agent.

Ask the Assistant

What level of support do you have?

Different subscription plans provide distinct categories of support. Find out the level of support for your plan.

View levels of support