Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: gabyanz on 2014-10-14, 21:24:06

Title: Help with vrayHDRI Dome light
Post by: gabyanz on 2014-10-14, 21:24:06

Hallo.. please forgive this probably stupid question, but I've searched  the forum with no luck.

I'm starting to use corona, and I've started do study the sample scenes.

If I try to use a vray light dome with vray hdri, the scene goes completely dark.

I've deleted the corona sun and cleared the sky from environment. Added the Vray Dome... and It simply does not work.

 have I to activate something? I can't get it work...

I know I also could put the vray HDRI into the enviornment slot, but I've read that's It will get less light samples...

thanks in advance
Gabriella

Title: Re: Help with vrayHDRI Dome light
Post by: borisquezadaa on 2014-10-14, 21:28:44

Just use it in the environment slot. No worries there.

Title: Re: Help with vrayHDRI Dome light
Post by: gabyanz on 2014-10-14, 21:33:30

Yes, but...

Why I read lot of people using them... and I simply can't make it work?

I'm trying to learn the program...

thanks again

Title: Re: Help with vrayHDRI Dome light
Post by: Juraj on 2014-10-14, 21:36:10

You're mixing up Vray and Corona.

Vray needs Domelight alone to do importance sampling but also to be sampled direcly. VrayHDRi map is used for convenience of use (360 rotation, easy gamma change).
Corona can't read VrayLights (it's Vray light...) but is able to read VrayHDRi map for convenience. Corona can sample environment (either 3dsMax environment or Corona render settings environment) directly and doesn't need any analytical light source to be present in scene for it.

Corona image based lighting workflow:

1) Load HDRi in either a)Bitmap loader {32bit floating point, gamma 1.0} or b) VrayHDRi map {in Vray3.0 don't forget to turn proper mapping, it's no longer only for spherical maps by default}
2) Place in 3dsMax Environment slot or Corona render settings Environment slot
3) Render final image

Title: Re: Help with vrayHDRI Dome light
Post by: gabyanz on 2014-10-14, 22:04:25

Thanks so much Juraj.

I've read (and heard) that I could use the VrayHDRI map, and I made the error to think that also the vray dome light was supposed to work.

So Corona does importance sampling also from the environment slot... instead Vray needs the dome light...

To improve the light solution (less noise,  faster result) , I should use portals in every windows?

In vray skyportals add lot of rendering time...

Thanks again
Gabriella

Title: Re: Help with vrayHDRI Dome light
Post by: Juraj on 2014-10-14, 22:20:36

Vray LightPortal is quite strange, but it's not good idea to use both Domelight + Portals at same time in Vray because they both will sample the light on top of each other.

In Corona it's quite simple and in lots of situation you can avoid portal completely, environment suffices, but if the window opening gets relatively small you can use them, they will only speed up the noise convergence, they don't alter light (unlike Vray, they're not light sources) or complicate sampling. Just the way you create them is maybe odd.. it's material that you should apply to (ideally 1 poly) plane, orientation shouldn't matter, in front of window openings.

Title: Re: Help with vrayHDRI Dome light
Post by: gabyanz on 2014-10-14, 22:27:22

Thanks again Juraj :)

I like a lot the thing that they do not alter the amount of light... In vray was a pain...

now it's time to go back for testing :)


GA