Render a spherical environment.
- [Instructor] Arnold makes it very easy to render out panoramas of various types, and we have options for anything from a single cylindrical or spherical environment up to and including full-motion stereoscopic 360 degree video. In this example, we'll just create a simple spherical environment map. There are two requirements for a spherical environment, or equirectangular projection. If we want it to work properly in a viewer, or a map properly, as a HDR image or background, then we need to have a level horizon line.
Select the camera in any viewport, and in the channel box we see that the camera's Rotate Z attribute is zero, and that's the rotation around the camera's line of sight, or it's canted angle or Dutch tilt. We want the horizon line to be level, so Rotate Z should be zero. Also notice that the X rotation value is zero. That's the tilt rotation for the camera, and it's important that it also has a value of zero.
Otherwise you'll get a weird wavy horizon line in your spherical panorama. Then when the rendering is loaded into a panorama viewer, the starting rotation for the viewer will be tilted up or down, rather than level with the horizon. So X rotation and Z rotation both have to have values of zero. The Y rotation, or pan, can be whatever you need it to be in order to frame the shot. Also for an equirectangular projection, so that the pixels are not stretched or distorted in any way let's make sure that it's a two to one aspect ratio for the rendering.
Open the Render Settings dialog, and in the Comment tab, scroll down to the image size, and I currently have a device aspect ratio of 1.778, and a pixel aspect of one for square pixels. We want the device aspect ratio to be 2.0. Let's set the height to be half of the width. Set the height to 320 pixels, and press Enter. Now we have a device aspect of two, a pixel aspect of one.
If we close the render settings, we now have a two to one aspect ratio cropping in the camera viewport. Let's open up the Arnold Render View. Click in the camera view to give it focus, and go to the menus and choose Arnold > Render. That's the rendering with the perspective projection and a field of view of 60 degrees. Let's now change this to a spherical environment map. Select the camera, and open up the attribute editor with control + A.
Scroll down to open the Arnold section if necessary, and here's the camera type. We've got a bunch of options here, and the most complex one is the VR camera. If we choose VR Camera, then we see two images side by side, and we're seeing the two left and right eyes in a single image. We don't need that in this case. We just need a simple, lat-long projection as seen here, but just across the entire frame.
And we don't need to worry about eye separation or any of that, if we're just doing a single image. So we can change the mode over here to Left Eye or Right Eye, and there'll be a little bit of an offset between those two but it won't be that obvious, depending upon the amount of eye separation here. But just to simplify things, so that we don't even need to worry about any of this, we can go up to the camera type, and simply set it to Spherical, and that's really all that needs to be done.
We've now got a spherical environment, also known as an equirectangular, or a lat-long projection. And that's how to use the Arnold camera type to render 360 degree stereoscopic video, or simply a single spherical panorama.
- Arnold rendering concepts
- Lighting with Maya and Arnold lights
- Controlling exposure
- Filtering light with Gobo
- Light attenuation with Decay
- Image-based lighting with Skydome
- Exterior daylight with Physical Sky
- Arnold Standard Surface material attributes
- Mapping material attributes
- Rendering refractions
- Mesh subdivision and displacement at render time
- Shading effects such as ambient occlusion and vertex color
- Camera effects such as fisheye and depth of field
- Animation image sequence rendering