1. It might be due to the IES files inside have special symbols, such as "? |". Special symbol cannot exist within IES file.
2. What is IES file:
IES standard file format, photometric data files in IES format can be created using the IES LM-63-1991 standard file format for photometric data. (IES stands for Lighting Engineering Association.) However, only the information related to 3ds max is described here. For a complete description of the IES standard file format, see the IES standard file format for electronic transmission of photometric data and related information developed by the IES Computer Board
The luminous intensity distribution (LID) of a light source is measured at a node of the optical network to obtain a set of fixed horizontal and vertical angles. The poles of the net are along the vertical axis and the lowest point corresponds to the vertical angle of 0 degrees. The horizontal axis corresponds to a horizontal angle of 0 degrees and the direction is parallel to the length of the light source. This type of optical network is generated by C-class goniometers and is most popular in North America; other types of goniometers supported by the IES standard file format are not discussed here.
Photometric data is stored as an ASCII file. Each line in the file must be no more than 132 characters in length and must be terminated with a carriage return or line feed sequence. Longer lines can continue by inserting a carriage return or newline sequence. Each field in the file must begin with a new line and must be accurately displayed in the following sequence:
[TEST] Number of test report data
[MANUFAC] Manufacturer of light sources
If the absolute metering method is used and the intensity values do not depend on the different lamp levels, the initial level lumen of the lamp is used in the test or -1. The multiplier for all the values in the file. This makes it easy to scale all the values of the Kendalla in the file when the device is measured in unusual units - for example, when the photometric values are obtained from a dialog box using a ruler on a goniometer chart. The multiplication factor is usually 1
The vertical angle in the optical network.
Horizontal angle in the optical network.
1 Unit type for measuring the size of the light-emitting opening. 1 for feet and 2 for meters.
The width, length and height of the light emitting opening. At this point, Lightscape ignores these dimensions, since the specified luminous intensity distribution can be associated with any one of the light source geometry bodies supported by Lightscape. Normally it is specified as 0 0 0.
1.0 1.0 0.0
The vertical angle settings are listed in increasing order. If the distribution is fully listed in the bottom hemisphere, the first and last angles must be 0 ° and 90 °, respectively. If the distribution is fully listed in the top hemisphere, the first and last angles must be 90 ° and 180 °, respectively. Otherwise, they must be 0 ° and 180 °, respectively.
The horizontal angle settings are listed in increasing order. The first angle must be 0 °. The last angle determines the degree of transverse symmetry that the intensity distribution shows. If 0 °, the distribution is symmetric about the axis. If it is 90, each region is symmetrically distributed. If it is 180, the distribution is symmetric about the vertical plane. If greater than 180 and less than or equal to 360, the distribution exhibits no transverse symmetry. All other values are invalid.
The settings for the Candela value. First list all the kendra values corresponding to the first horizontal angle, starting at the value corresponding to the minimum vertical angle and moving the associated vertical plane upwards. Then the Kandler values corresponding to the vertical plane by the second horizontal angle are listed, and so on up to the last horizontal angle. Each vertical slice of the value must start at a new line. According to the instructions previously specified, open a longer line between the values on demand.
3. Load error solution:
a. Use Notepad to open IES file:
b. Delete the special symbol and save the file:
c. Open the 3ds Max file to reload a new file.