Different image between first render and other render

[tue_nguyen]

I don't know why but when i use region render with IR+LC. The image region is different before version. Nothing change about lighting.

[werticus]

irradiance map is a rough approximation of the lighting that is randomized somewhat and if you do a region render you will get that issue...as the samples are different / over a different area.

[tue_nguyen]

irradiance map is a rough approximation of the lighting that is randomized somewhat and if you do a region render you will get that issue...as the samples are different / over a different area.

I think same with you. But i don't think the problem is big problem. And with other scene it's not happen.

[werticus]

don't use region render for final renders is the basic rule... if you have to, eg for a quick fix up, do a large enough area around the region to blend it in smoothly.

[tue_nguyen]

don't use region render for final renders is the basic rule... if you have to, eg for a quick fix up, do a large enough area around the region to blend it in smoothly.

Thanks you but i'm a little surprise. I'm use vray from 3.x version and it's not problem. This is first time of me.

[werticus]

Hrmm this has always been an issue with IR map, you might not see it on exteriors but interiors... always :P
I've been using vray since 1.5

[^Lele^]

Any interpolated method always behaved like this: irMap, LC, and so on.
Because by cropping you effectively reduce the screen size (you'll notice the samples line up with the area edges, not the image edges), and as such at the very least one gets a different sample distribution.
Often, if the area is small, and the lighting difficult (ie. interior), there will be also a visible brightness difference, thanks to a different result of said interpolation.
It of course becomes more visible in broad gradients, rather than high-frequency detail, like in your case.

[tue_nguyen]

Thanks you for it.