V Ray dome light Parameters

[Anonymous]

I'm using Maya 2019 w/ V Ray and illuminating a scene w/ an HDR image mapped onto a V Ray Dome light. I'm able to rotate the HDR, but not able to control any other placements of it when selecting the "Use Transform" option- it's hard to tell which "Transform" options affect anything and I've also tried the "Ground On" option w/ no results. I've looked at the documentation but it doesn't explain this, so any clear info is appreciated, thanks

[damaggio]

Just use transform and rotate the dome

[Anonymous]

Thanks, but only the Horizontal Rotation command seems to work, and I'd like to be able to move the HDR image either closer towards the model, or lower the horizon. As I mentioned, when I activate the "Use Transform" option, nothing seems to be affected (pls see the attachment). It appears the Dome Light can't be moved manually-

[damaggio · Accepted solution]

thats not how it works, the dome is infinite, you cannot move any closer, you can use different focal lenses or compose against a backplate ( that’s the professional approach) or you can use a poly sphere for more control over scaling it with the HDR map applied to it...

or use HDR set reconstruction technic. 
for the ground you need a plane with a Vray Material Wrapper or a real poly plane with asphalt/ road texture.

[Anonymous]

Thanks again, but my question was how the "Transform" and "Ground On" options work (pls see previous attachment). This particular HDR doesn't contain any backplates and I wanted to use the V Ray dome light-

[damaggio]

Hi Ted, I be never used the ground setting so I don’t know how it works , if you don’t have backplates than you might need to play with the camera lens or find another HDR image, with or without plates.

[damaggio]

You could also look for more free tutorials on YouTube or buy one at Gnomon workshop school or FXphd and other online schools.

[Anonymous]

Thanks once again! I've looked at tutorials and haven't found any decent info on these particular settings and was hoping this forum would "shed some light". Autodesk only offers general info w/o any clear explanations- more or less just definitions that don't help. My understanding is that the Dome Light is infinite, but it seems these Parameters somehow control it. I've tried randomly entering numbers into the slots without any results, and just ended up distorting the HDR image at one point. Selecting the Dome light and moving it doesn't seem to do anything. Oh well...

[damaggio]

That’s correct Ted, now if you want a better explanation of this setting you should post your question to the proper Vray forum at Chaos Group, Autodesk does not develop this software.

[damaggio]

You could also just keep on working with lighting your scene and leave the ground option for later once you know more about it.

[Anonymous]

 I didn't realize that, but thanks for pointing that out now!

[damaggio]

No worries Ted, happy new year and beautiful renders for 2020.

[damaggio]

Yeah, the ground on just flattens the bottom HDR image to resemble the floor thus providing better reflections and lighting. An interesting new feature.

[Anonymous]

Thanks- I will try that and contact Chaos for more info on the parameter settings- here's what I've gotten so far-

[damaggio]

Looking good, i also have a free desert Hrdi with some backplates if you wanna put in a different environment....

https://www.turbosquid.com/FullPreview/Index.cfm/ID/925039

[Anonymous]

Thanks!- I've been using HDR Haven and not all contain backplates

[damaggio]

Yes , it’s a fantastic site, thank god for that guy.