Changing Arnold skydome hue


#1

I’ve been trying for days to get an HDRI image in an Arnold skydome light to render true daylight sky blues. For some reason invariably when I render the image the light coming from the skydome shifts the blue hues toward cyan enough to be irritating. I need it to appear as bright daylight, so I can’t turn down the intensity or exposure without loosing the brightness in the entire scene. Is there any way to have actual control over the hues and colors of a skydome so that the sky color and light in the scene is true to the original images?

(This is in Maya 2020 with MtoA 4.0)

I’ve been checking this with a plane that has an image file applied made from a daylight terrain photograph. If I use a normal Maya material and Maya lights (Directional and/or point lighting) the terrain color shows true color as it should, and testing a sample of the blue sky also gives fairly accurate blues as expected. So normal Maya lights give true colors, so to speak.

But, I’ve tried a variety of HDRI images for the Arnold skydome, specifically using ones that show clear blue skies, like desert skies, and with as few clouds as possible so the blue is nice and clean. But whenever I render the image using the skydome lighting, both the sky hues from the HDRI image as well as the hues on the terrain are shifted toward cyan. I’ve tried everything I can see, even using color temperature but I still can’t get the real blue daylight sky color that it should be. I’ve even opened the image in Photoshop to compare the actual image I start with to the rendered image using Arnold Renderer and the outcome is always shifted toward cyan hues.

I did try using the Arnold Color Corrector node, but apparently the node doesn’t function if the end result is a skydome (works in other instances/images…but not the skydome, at least not that I’ve found.)


#2

it would be helpful if you posted some images
blue skies can cast blue light

if it looks unrealistically blue, it might be a hdri where the sun is clipped/not bright enough or painted out
i recommend looking for hdri’s on hdrihaven.com/
they are all free and values are not clipped

another thing you can do if you still find it blue using a good hdri is to white balance the image
i’ve tested color correct node for skydome, it works fine for me


#3

If the intensity is above 1.0, it is clipped, at least in the viewer. Sky blue always has a litle green in it, so when you increase the overall intensity, the color starts to look cyan, because the green is visibly increasing while the blue is still clipped at 1.0.

But if you’re using an hdr, you should not have the dome’s intensity above 1.0. Then it should look like it normally does in other viewers.

The only way to have a “true” sky with the real intesity is to have a true hdr display, one that display colors well above 1.0.