L'Adair's Kitchen… (How'd She Do That?)

L'Adair

Using a 3DL Skydome in Iray

While using Render Settings > Environment for lighting the scene.

It's been years, and several versions of Daz Studio, since Iray was first introduced and Will, (@Oso3D,) shared his technique for using a 3DL skydome in Iray. His instructions work just as well today, but for anyone new to DS, they can also be rather cryptic. As this question has come up again, I decided to write up this mini-tutorial with new users in mind. (A great big Thank You to Will for sharing the steps in the first place.)

1. Load the skydome into the scene and select it.
2. In the Surfaces > Editor, select the skydome and apply the Iray Uber Base.
   (Objects must be selected in the scene, and their material zones selected in the Surfaces > Editor for the Iray Uber Base to apply.)
3. Also in the Surface > Editor, change the following parameters:
   • Glossy Color: Add the skydome image to the image channel. Leave the color selection at White, (1.00, 1.00, 1.00)
   • Glossy Weight: 0.00
   • Glossy Roughness: 0.00, (In DS 4.11, I had to bump this up to 0.04 for the color of the dome to display in my test scene. YMMV.)
   • Glossy Reflectivity: 1.00
4. In the Render Settings > Environment
   • Apply one of the following:
     • Set Environment Mode to Dome and Scene; Click on the image for Environment Map and select None.
       OR
     • Set Environment Mode to Sun-Sky Only
5. In the Viewport, in Perspective View and the skydome selected, click on the "+" icon, (or use the keyboard shortcut, Ctrl+F).
6. Rotate the viewport until you can see the sun of your skydome.
7. In the Render Settings > Environment, adjust the following settings until the sun of the environment is aligned with the sun of the skydome
   • SS Lattitude
   • Dome Rotation
8. In the Surface > Editor, with the skydome selected, set:
   • Refraction Index: 1.00
   • Refraction Weight: 1.00
   • Glossy Reflectivity: 0.00

 

Using an image in the Emissive Color channel

One of my favorite tricks is to use the Diffuse/Base Color image in the Emissive Color parameter of a Material Zone. It doesn't work well for lighting if you need to render the image, imo, but it is a great way to bring out the details of the image that otherwise are lost. It doesn't matter what the object is, but the higher the polygon count, the longer it will take to render. (Iray needs to calculate how the light affects the entire scene, for each and every emissive polygon.)

I really don't recommend this method for a skydome, in general, because it will take longer to render. But for those with really good Nvidia graphics cards, it may be a non-issue. With this method as a lighting source, the light is coming from all directions and won't produce realistic shadows, you'll still have to add standard lights.

Regardless, here's how:

1. Load the skydome into the scene and select it.
2. In the Surfaces > Editor, select the skydome and apply the Iray Uber Base.
   (Objects must be selected in the scene, and their material zones selected in the Surfaces > Editor for the Iray Uber Base to apply.)
3. Also in the Surface > Editor, change the following parameters:
   • Emission Color: Add the skydome image to the image channel. Leave the color selection at White, (1.00, 1.00, 1.00)
   • Emission Temperature (K): 0.00
   • Two Sided Light: Off
   • Luminance: 10
   • Luminance Units: kcd/m^2
4. Adjust these parameters as necessary to get the effect you want.

These same settings can be used for any material zone you want to make emissive. For example, I used these settings for the framed photos in this render, because the branches and water at the bottom just looked black otherwise:

And in this render, I used these setting on the plane outside the window:

And in this Christmas image, outside the window, there is an emissive plane with a photo I took locally of a house with holiday lights and snow: