user_iblc_env with procedural or color input ?

[MiniZun]

Hi !

I did some test with the new user_ibl shaders and I found that the user_ibl can only takz inputs of type file. it's not a pribleme if we want to use a hdr file, but it's not possible to use a simple ramp or constant color. Exept if we bake it into a file.
So is there a way to use color inputs instead of file inputs ? is that a hard limitation in the fonctionnement of the user_ibl ?

I also noticed that the environment is fliped and rotated for 180 degres when compared to the native ibl when plugin the same hdr in an environment lookup.

I know there was the same flip issue with the old ibl node. so which is the good one now ? rotating the ibl is easy, but fliping it means doing it in another programme. the user_ibl seems to ignore the place2dTexture when using a maya file instead of a mentalRay file.

edit: could a moderator correct the error in the title ? (the "c" in user_ibl_env), I can't change it. thanks !

[Remydrh]

The old IBL (the one in Maya) has always been flipped incorrectly. The user_ibl_env is correctly positioned.

The native IBL would take what was plugged into the camera as an environment and bake it to texture (using the resolution string option) In that way it would take a procedural or ramp but you may have lost detail in the baking process.

user_ibl_env has direct access to an un-resized texture. So if you needed a procedural you would need to bake it to be sure it worked correctly and apply as an HDR texture.

If your HDR was acquired normally you should not need to flip it, this is unlike the Maya IBL connection that required flipping. The user_ibl_env should remove that step.

[MiniZun]

What I don't understand is why I have different flip result with native IBL and user_ibl_env when using the same hdr file. Both have a different position.

Do you know any way to bypass the need for a file ? I don't understand why there is this limitation

[Remydrh]

Is the native IBL you're using by plugging a texture into the Maya IBL connection?

And there's not a bypass I know of, it requires a texture. Other connections don't work well for me. (crash or error) It's not really a limitation, it's DCC package agnostic so it accepts a texture.

To be honest, procedurals tend to produce muddy lighting.

[MiniZun]

Ah no, I never use the maya IBL, when I refer to using naitve IBL, I'm using a mi_lookup_spherical plugged in the miEnvironment slot of the camera.

And for the procedural, I just wanted to use a simple ramp (vertical light grey to dark grey) as ibl lighting and area lights for main lighting to simulate a studio.

[Remydrh]

I think mi_lookup_spherical uses radians and user_ibl is degrees. That might be part of the problem.

Procedurals are convenient but not always the best choice. You can probably make some nicer ones in Nuke or HDR Light Studio.