Twilight Render User Forum

I'm working with IES files and tried different ones without issues. On the Philips professional website there are hundreds of IES fiels available and well documented photometric informations. I'm not a field expert, but it's quite hard to find such a great amount of free resources.

The issue is that some IES files can't be loaded into Twilight Render. Some lamps models have different lumens, so I can download IES for each lumen and kelvin. Some of them result in invalid IES files, while the majority can be loaded.

For example, this is a link where you can find a mix of them:
https://www.lighting.philips.it/prof/la ... &layout=50

• 1270lm LED bulb with a valid IES file: https://www.lighting.philips.it/prof/la ... EU/product

• 620lm LED bulb with an invalid IES file: https://www.lighting.philips.it/prof/la ... EU/product

I tried to load both IES files on the AcuitiBrands Visual Photometric Tool ( http://www.visual-3d.com/tools/PhotometricViewer/ ) and they work, but there's a note saying:

**File does not include sufficient vertical data to properly calculate BUG and LCS uplight.
**File does not include upper hemisphere data(90-180) and has Cd > 0 at 90° vertical.

It's able to generate a report. This is why I think Twilight is a bit more strict, or may be this is a sort of bug? The strange fact is that TWR loads only the 1270lm IES file..

We will take a look. Thanks for the info!

While I can't say for sure, I'm guessing you are correct that Twilight Render is more strict on the expected format of the IES files. But maybe that is something we can change to still handle the file even if there is a possibility of errors.