SP3 / use LC for glossy = slow

[cgrant3d]

I have a large exterior environment I'm rendering and couldn't have been more surprised that after computing a LC in flythrough mode and changing LC to load precomputed my render times go through the roof. The frames are supposed to be about 4 minutes but were actually taking about 40 minutes to render. Its now reproducible where all I have to do is uncheck "use LC for glossy rays" and hit render and my render times go back to normal.

This seems to only be a problem when using a precomputed LC in flythrough mode - single frame works fine whether the glossy rays option is on or off... I've created a separate simple scene file and haven't been able to get it to reproduce the error yet so its something screwy with my scene. Anyone have any ideas? Seen anything similar to this?

Thanks,

[vlado]

It may happen if V-Ray cannot find suitable light cache samples for interpolation. In these cases increasing the light cache subdivs and/or reducing the light cache filter interpolation samples will help.

Best regards,
Vlado

[cgrant3d]

It may happen if V-Ray cannot find suitable light cache samples for interpolation. In these cases increasing the light cache subdivs and/or reducing the light cache filter interpolation samples will help.

Best regards,
Vlado

Thanks so much for the heads up. I don't know why but my LC filtering was set to nearest when I usually use fixed. Changing to fixed dropped my render times even further - down to 2.75 min / frame.

So - my initial assessment was this was somehow tied to SP3. It seems now its more like user error (oops). Maybe you could change the thread title to "use LC for glossy = slow" so nobody incorrectly things SP3 is to blame.

[sheepishly thanks vlado and goes back to work]