Difference in shading between VrayIES and Photometric lights

V-Ray V-Ray Common Render Theory
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1

I have been testing vrayIES and the photmetric lights and there is a difference between how the intensity is showen or shaded.

so i checked the lightlevel with the vraylightmeter and it turns out that the levels at the same, but the photometric light looks brighter in the render.

which one gives the correct result???

vrayiesphotometric.jpg
vrayiesphotometric.jpg1550×969 510 KB

2

Do you have any exposure control applied? Can you post the .ies profile here?

Best regards,
Vlado

3

Yes the vray exposure (no vray cam)
BCS713 12xLED-K2-Q00_WW 6.ies.txt (1.07 KB)

4

Just made a simple test with your file, you can see it below:

I’m using the same values (Lumen and Color temperature/Kelvin) for both, V-Ray IES and 3DS Max photometric lights. Also V-Ray exposure control is enabled.

test.jpg
test.jpg640×480 4.84 KB

Light.jpg
Light.jpg1064×872 158 KB

5

Try and turn the lights 90deg (z-axis) and set them both to Area lights the luminaire is 30cm long and it is placed 10cm from the wall

I’ll attach a max file later

6

Could you post your scene file to test with it?

7

There is an issue with 3dsmax photometric lights and european ies files:
3dsmax is placing the C0-C180 Axis of ies file always on the length axis without checking if it’s correct.
Vray seems to load the ies differently ..vlado?