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[Max] Feature Requests / Improved behavior of IES lights
« on: 2020-01-10, 10:08:47 »
Hi!
According to my searches, a few years have passed since IES behaviour was brought up on the forum, and it seems nothing has happened in terms of improving the weird behaviours noted by users. I am slightly dissapointed that it isn't more of a priority.
I realise that this topic isn't crucial for people in Archviz, but for many people working with corona in lighting design, product design, interior design and architecture, I believe it is important.
Firstly I would like to mention that I work as a lighting designer, and regularly use photometric files (incluing IES) in other calculation software, so I feel like I have quite a good understanding of what an IES file is, what information it contains, and how it can behave in software.
I just spent some time in a test scene checking the behaviour of corona lights and 3ds max photometrical lights with and without IES files.
Below is a list of things that I find strange..
- IES files contain information about the intensity of a fixture. This information is not used when loading an IES file with a corona light, but must be input manually. It is however used when loading an IES file with a photometric light, which seems more logical to me.
- If I try to set up a corona light, and a photometric light, loading the same IES file into both, and adjusting the lumen values of both to be identical, the resulting intensity in my rendered image is not the same. This is problematic because you can't count on intensities when using corona lights and photometric lights in the same scene. I often need to do this in scenes.. For me photometric lights work better with IES files, and Corona lights work well for generic spots, where you can quickly adjust directionality. I use corona lights as well for simulating linear fixtures such as LED strips.
- When using a corona light with an IES file, the light can be set to disc and sphere with the same result as long as intensity is set using the 'default' setting. When using the 'lumen' setting however, the disc and sphere lights have different intensity. This seems very illogical?
My feature request to improve IES file behavior in Corona would be the following:
- Corona lights automatically read the intensity (lumen) values in an IES file.
- When an IES file is loaded into a corona light, it should disable the shape picker drop down. The IES file should lock the shape of the light to a sphere with a predetermined size. IES distributions are by default spherical.
- A corona light and a photometric light loaded with same IES file, with the same lumen intensity, should render the same.
- When using corona lights without IES files, it would be great to be able to adjust light intensity as lumen/area. This way it would be possible to create rectangular lights of different lengths in a scene and give them the same intensity (think LED strips that have a certain lumen output pr. meter). I know this is possible to do with a corona light material, but comes at a cost of lower render performance.
- Many european lighting manufacturers don't provide IES files, but instead provide Eulumndat files (.ldt). IES is an american standard and LDT is a european one. It is possible to convert ldt to ies and vice versa, but it would be more elegant if corona lights could load both file types.
- Finally on a more general note: Could the Interactive LightMix interface have a GUI option to look like a fader panel (as in Maxwell render multilight GUI). Optimally with the option to control it via physical faders using a MIDI interface. This would be a game changer in presenting architectural lighting design to clients.
All feedback, corrections and comments are welcome.
Best regards - Christian
According to my searches, a few years have passed since IES behaviour was brought up on the forum, and it seems nothing has happened in terms of improving the weird behaviours noted by users. I am slightly dissapointed that it isn't more of a priority.
I realise that this topic isn't crucial for people in Archviz, but for many people working with corona in lighting design, product design, interior design and architecture, I believe it is important.
Firstly I would like to mention that I work as a lighting designer, and regularly use photometric files (incluing IES) in other calculation software, so I feel like I have quite a good understanding of what an IES file is, what information it contains, and how it can behave in software.
I just spent some time in a test scene checking the behaviour of corona lights and 3ds max photometrical lights with and without IES files.
Below is a list of things that I find strange..
- IES files contain information about the intensity of a fixture. This information is not used when loading an IES file with a corona light, but must be input manually. It is however used when loading an IES file with a photometric light, which seems more logical to me.
- If I try to set up a corona light, and a photometric light, loading the same IES file into both, and adjusting the lumen values of both to be identical, the resulting intensity in my rendered image is not the same. This is problematic because you can't count on intensities when using corona lights and photometric lights in the same scene. I often need to do this in scenes.. For me photometric lights work better with IES files, and Corona lights work well for generic spots, where you can quickly adjust directionality. I use corona lights as well for simulating linear fixtures such as LED strips.
- When using a corona light with an IES file, the light can be set to disc and sphere with the same result as long as intensity is set using the 'default' setting. When using the 'lumen' setting however, the disc and sphere lights have different intensity. This seems very illogical?
My feature request to improve IES file behavior in Corona would be the following:
- Corona lights automatically read the intensity (lumen) values in an IES file.
- When an IES file is loaded into a corona light, it should disable the shape picker drop down. The IES file should lock the shape of the light to a sphere with a predetermined size. IES distributions are by default spherical.
- A corona light and a photometric light loaded with same IES file, with the same lumen intensity, should render the same.
- When using corona lights without IES files, it would be great to be able to adjust light intensity as lumen/area. This way it would be possible to create rectangular lights of different lengths in a scene and give them the same intensity (think LED strips that have a certain lumen output pr. meter). I know this is possible to do with a corona light material, but comes at a cost of lower render performance.
- Many european lighting manufacturers don't provide IES files, but instead provide Eulumndat files (.ldt). IES is an american standard and LDT is a european one. It is possible to convert ldt to ies and vice versa, but it would be more elegant if corona lights could load both file types.
- Finally on a more general note: Could the Interactive LightMix interface have a GUI option to look like a fader panel (as in Maxwell render multilight GUI). Optimally with the option to control it via physical faders using a MIDI interface. This would be a game changer in presenting architectural lighting design to clients.
All feedback, corrections and comments are welcome.
Best regards - Christian