[Arnold] Rolling shutter in a nutshell

What’s rolling shutter? It’s an effect, or artifact, that looks like like this:

Rolling shutter means that the image isn’t captured all at once, but one scanline at a time:

Lee posted a video walk through of how to get the rolling shutter effect with Arnold. He used C4DtoA, but it’s basically the same recipe in any of the Arnold plugins:

  • Your geometry has to be spinning fast (like a propeller 😉
  • Select your camera, and enable Rolling Shutter. Leave the duration at 0.
  • In the Render Settings, enable motion blur (you don’t need deformation blur, or camera blur).
  • Adjust the number of motion keys, and the shutter length, to taste. As you increase the shutter length to exaggerate the effect, you’ll need more motion keys.

Update: And here’s some more interesting experiments with the rolling shutter effect

[HtoA] Using custom Arnold cameras in Houdini

Here’s how to set up your custom camera in Houdini. I’ll use the Oculus camera as an example.

  1. Copy OculusCamera.dll and OculusCamera.mtd to your HtoA arnold\plugins folder. For example, on my machine, that’s here:
  2. In the Shop network, create an Arnold Shader Network.
  3. In the Arnold Shader Network (arnold_vopnet), create an Camera > Oculus Camera and an Output > Camera Output. Connect the Oculus Camera to the OUT_Camera.
  4. In the Obj network, select your camera, and in the Camera properties, set the Camera Shader to point to your arnold_vopnet.

[SItoA] Disabling camera motion blur

Starting with version 2.8, SItoA no longer supports the Softimage motion blur property. Instead, you use the Arnold Parameters property to control transformation and deformation motion blur.

However, you cannot add an Arnold Parameters property to a camera (at least not using the SItoA custom menus, which will tell you that a camera is “is not a valid Object to add Arnold Parameters to”). Here’s a couple of ways to work around that:

  • Create an Arnold Parameters property on a polygon mesh, and then in the Explorer, drag that property to your Camera.
  • Select your camera and run this Python snippet:
    cam = Application.Selection(0)
    cam.AddCustomProperty( "Arnold_Parameters" )