render to texture gi problem on backface

[thomes]

hello,

i render a rawtotallightingmap of an object and on one backside of a wall i see gi artefacts of objects that are on the other side of the wall ( distance of the thin wall faces, about 1cm). with AO rendered into the image it gets even worse. but still without AO you can see artifacts (a vertikal wall and in the middle a tv. as i said they are about 1 cm away from this face. illumination map has 100 subdiv / interpolsamples50 with "veryhigh" presets. lightcache as secondary has subdiv1500 sample size 0,01. where to screw to get rid of this? i tried detail enhancement with radius of 5 /screen /subdivmult 0,3 but that did not help.

any idea?

thanks a lot
thomes

vray 4-20-00 on max2019

[thomes]

anyone from chaos? aleksandar,vlado?

[hermit.crab]

Try the suggestion from this thread.

[thomes]

thanks for help aleksandar , both did not help or make it better

[hermit.crab]

In that case, do send the simplified scene via the contact form over so we can take a look. Address it to me in the subject and mention this thread in the message.

[thomes]

hi aleksandar, i send the small file. you can delete all the lights. the problem is related with only the irradiance map as itself. maybe you could check if you find something in the values.

[thomes]

if i render lighcache only, this first problem is away, but i have another one in the vrayrawtotallighting. you see the round artifacts... if i disable the vraylightdome it is away. so what is the problem here?

[thomes]

if i uncheck "adaptive dome" in the domelight parameters the artifacts are away... ok...so maybe this is the solution. no irradiancemap and no adaptive dome.

[thomes]

anyway aleksandar , it would be good to know if these two things have a problem , or if i made a mistake....

[hermit.crab]

Thanks for the provided scene. I can't seem to locate the specific problematic area from the screencap, however.
It is not your mistake, it was a reoccurring issue with the adaptive dome light. However, the majority of those issues are already fixed in V-Ray 5.

[thomes]

thanks alek for your time, the dome-thing i understand, but is with the irradiance map problem?

btw. the region i showed is here:

[hermit.crab]

Seems like more of a mapping issue than anything else. Packing only the particular wall backside in an individual unwrap does not produce anything out of the ordinary. You may try re-adjusting your Unwrap.

[thomes]

you`re quite right ! some faces were scaled down and rearranged (without rescaling) in the unwrapper because of priority things. if you render the regular weighted unwrapped faces the render error is away. i did not think that this could come because of the faces downscaling. so it seems more of a max error you think...

thanks a lot for your help !

here the same face, same rendersettings, unscaled... nearly everything ok as it seems . but you can even still see a little bit of the monitor (of the other side of the thin wall) in the middle of the face. but its getting quite worser with the downscaling...