hi,
i have the following problem with a flythrough:
this image was rendered with a fresh “single frame” IMAP + “flythrough” LC. it’s fine.
this image was rendered with the same saved “flythrough” LC, but with a “multiframe incremental” cached IMAP.
i get the same problem with all methods of incremental IMAP rendering.
anyone got a quick idea what could be the problem?
thanks
Are you using an animated exposure?
We ran into similar issues in our last job that was using animated exposure. We also saw bright splotches in some scenes.
Is the camera the only thing that is animated?
Best regards,
Vlado
Vlado, do you foresee any issue with mixes imaps created with very different exposures?
Well, V-Ray takes exposure into account when doing its calculations. So if you have a scene where you make a transition from exterior to interior, you might get issues when parts of the interior are visible from the exterior shots. This is because they will be very dark, and V-Ray will use low-precision samples there. Later on, when the camera moves in the interior space and these areas are brightened, the lower precision will show up as splotches.
There are several ways to deal with this; one is to use a constant exposure when calculating the irradiance map; another is to decrease the Noise threshold of the DMC sampler and increase the Min. samples.
Best regards,
Vlado
Thanks Vlado, that makes sense.
Sorry plastic_ for jumping all over your thread, hope this is your issue too. 
hallo RErender and vlado,
i don’t use animated exposure.
the only thing animated is the VrayPhysicalCamera & target.
maybe it’s something with the glossy reflection on the floor…i have to narrow it down.
Vlado, it’s the “detail enhancements”, using the default 1.5 values, screen/60/0.3.
when i turn them off everything is fine.
Ah. With fly-throughs you must use the “World” scale for the detail enhancement.
Best regards,
Vlado
I see…makes sense…
thanks Vlado.