Question about rotating HDRI lighting. *SOLVED*

Fae3D

I really should be able to figure this out, but I'm having a major brain glitch for some reason.  I'm using an HDRI for lighting, one that came with Great Lights and Props for Iray.  But my subject is lying flat on the floor.  So I want the light that would normally be falling on her face in a portrait-style picture to hit her face on the floor.  I see that there are options for rotating the enviroment under Render Settings, but I can't seem to figure out which way to rotate on what axis.  My computer renders VERY slowly, and it's a large file, so lots of trial and error means hours and hours of rendering.

Does anybody have any idea what I mean?  I'm probably not explaining this very well, but math was never my strong point!  Any help would be greatly appreciated!

 

Edit - In this particular case, adjusting the Z Axis by 45 positive and the Y Axis by 90 positive seemed to do the trick.  Just in case this might help someone else in the future. 

Lyoness

may I suggest that you turn on Filament.

Then use dome rotation, and spin that dial!  You can see it move in real time, and you can see the background at the same time.
This is a new technique that I've learned that is super handy.

Fae3D

Lyoness said:

may I suggest that you turn on Filament.

Then use dome rotation, and spin that dial!  You can see it move in real time, and you can see the background at the same time.
This is a new technique that I've learned that is super handy.

Unfortunately, I can't use Filament, as I am on a Mac.  Thank you for the info, though, maybe we will eventually get Filament!

chris-2599934

I don't know if this product would work in your rig: https://www.daz3d.com/ibl-master-for-daz-studio

For a cheap and dirty alternaive, maybe you could create a null at (0,0,0), then place a primitive off to one side in the direction your main light is coming from and parent it to the null. Then you can rotate the null untill the primitive is where you want the light to be, and copy the x,y,z rotations across to Dome Orientation X, Y, Z in the environment part of your render settings. Delete/hide the primitive before you render, of coure. It will still leave you a lot of fine-tuning to do, but may save an hour or two.

ColinFrench

Fae3D said:

I see that there are options for rotating the enviroment under Render Settings, but I can't seem to figure out which way to rotate on what axis. 

I use positive values for the Dome Orientation Z-axis rotation, e.g. "20" to move the light so it's shining in a more downwards angle towards the character.

I'm assuming you're not drawing the HRDI as a background, just using it as a light source. Using it as a background would likely look pretty strange if you rotate it on the Z-axis.

Fae3D

chris-2599934 said:

I don't know if this product would work in your rig: https://www.daz3d.com/ibl-master-for-daz-studio

For a cheap and dirty alternaive, maybe you could create a null at (0,0,0), then place a primitive off to one side in the direction your main light is coming from and parent it to the null. Then you can rotate the null untill the primitive is where you want the light to be, and copy the x,y,z rotations across to Dome Orientation X, Y, Z in the environment part of your render settings. Delete/hide the primitive before you render, of coure. It will still leave you a lot of fine-tuning to do, but may save an hour or two.

I do have that product, but for some reason it wasn't really working with this scene.  I tend to forget about it, but it is usually a very good resource!  Thank you!

Fae3D

ColinFrench said:

Fae3D said:

I see that there are options for rotating the enviroment under Render Settings, but I can't seem to figure out which way to rotate on what axis. 

I use positive values for the Dome Orientation Z-axis rotation, e.g. "20" to move the light so it's shining in a more downwards angle towards the character.

I'm assuming you're not drawing the HRDI as a background, just using it as a light source. Using it as a background would likely look pretty strange if you rotate it on the Z-axis.

Changing the Z Axis positive did seem to help, thank you very much!!!