#Intensity single light source equation pdf

My light was white (6500K) and to get that wavelength, I averaged the top and bottom numbers on this converter and I came up with: My problem was: what the heck was “color”? After some more looking around and testing, I guessed that “color” might be the actual light wavelength of the source light. So to get the intensity value I needed for threejs: So after combining the formulas into a single equation, I got: Intensity – Unit of light measurement used by Threejs, second part of the threejs candela calculation Lumens – This seems to be an unnecessary intermediary conversion, but it keeps the formulas simplerĬandela – Unit of light measurement used by GLTFĬolor – According to Threejs documentation part of the formula for candela calculation Watts – Unit of light measurement used in blender KV = 683 – This is a constant related to the modern definition of the candela So I tinkered around a bit and finally found something that seemed to make it work. But unfortunately the formula that provided seemed to still be missing something when I tried to implement it.

So, as I mentioned above and as helped me out with, I found some conversion formulas in a github post that discussed this issue. But I wanted it to be as close to the original as possible since this 3d implementation was going to be only one of the uses across multiple platforms. I found that a value of about 10% of the original “Watts” value from Blender was pretty close. Before I posted initially, I just tried to eyeball the correct intensity values for the lights that were imported from the Blender GLTF. Hello! I just wanted to follow up with my findings on this issue in case it could help out anybody else in the future. I guess first figure out what units Blender uses for them and then try to find a conversion formula. I’m also not sure what you need to do for directional lights.

#Intensity single light source equation pdf

If not, you’ll have to study the linked PDF from that issue to figure out the correct formula. Note this is a guess, I would test a simple export with one spotlight from blender to see if it gives a decent result. Or in other words, for a spotlight with an angle of 90 degrees, 1 watt = 217 candela. If you put Φe = 1 (watts) in the point light conversion calculations you get a ratio:Ĭandela_ = 217.4

Ah, until they fix that bug I guess you’ll have to perform the conversion yourself.