On some built-in utility image planes, such as ‘Op_Id’ The screen door sampler is disabled for all sample filters. This makes it possible to add an operator id image plane to semi-transparent objects such as volumes.

Is there a sample filter available that will enable this behavior for user image planes? I would like to be able to export position and id passes for volumes, but it doesn't seem to be possible. All of the built-in sample filters either do screen door filtering or opacity filtering or both, none of which are acceptable for purely data image plane. The ifd does not appear to contain any specified sample filter for the Op_Id image plane, so perhaps mantra knows what to do with this one, and does not use the plane sfilter ray_property.

To summarize:

• An image plane with sfilter closest will apply screendoor sample rejection – which is undesired for position/normal/id data.
  
• fullopacity disables the screendoor filter, but causes samples to be integrated over opacity.
  
• opacity integrates the non-rejected samples over opacity, which is even worse.
  

additionally to Closest you can set the pixel filter to: minmax idcover

or you can try other modes of minmax filter as well