Something is wrong with my vrayIES

[pailhead]

There's one vrayies and one normal ies turned on in this scene. They both use the same .ies file, but as you can see, the yellow one (vray) has a really sharp border around it. If i move the vray light further up from the illuminated survace, it will show as a really sharp circle, rather than a soft distributed light.

[JohnVK]

Could this be caused by the cutoff value or the "use light shape" checkbox? Do these properties have the same value for both lights? Maybe one light has a higher power value?

Just throwing some suggestions at ya. Don't really know the actual reason

Edit: never mind, you're using a normal IES and VRayIES... doh...

[pailhead]

It was the cutoff parameter. Changing it to 0 will result in a proper distribution. What's the cutoff for anyway? 0.001 creates these rough edges, 0.01 turns off the light completely.

[JohnVK]

I suppose it has to do with "cutting off" the shape of the IES from top to bottom like when they are placed in / to conform to a light fixture? Not really sure actually.

The cutoff parameter influence also depends on the IES file you're using. The value 0.01 doesn't always completely cuts off the light

[pailhead]

I just hope that by setting it to 0.0 i am not doing harm in some other place. Like the render times...

[JohnVK]

Well, the higher the cutoff value (= less light distribution) the faster it renders. But I think that's normal. More light, so more to calculate . It doesn't make a whole lot of difference in render time though (the exact difference depends on the complexity of the IES data and the cutoff value). It does, however, make a whole lot of difference in the light distribution