projector's light can't walk through polarizer or circular

[guge2]

I am simulating a scan system. Use a projector and camera, everything going on util polarization are needed, there are some code of me:

'filter1_shape': {
      'type': 'obj',
      'id': 'filter1',
      'filename': str(data_root / '../scenes_mitsuba/meshes/rectangle.obj'),
      'bsdf': {
          'type': 'circular',
          'left_handed': False
      },
      'to_world': mi.ScalarTransform4f().translate([0, 10, -object_mean_distance+100])\
                  .scale(20*scale_to_meter).rotate([0, 0, 1], angle=45)\
                  .rotate([0, 1, 0], angle=180)
  },
"emitter": {
      "type": "projector",
      "irradiance": {
          "type": "bitmap",
          "filename": photo_abs_root
      },
      "scale": 0.05 * 1000000 / scale_to_meter / scale_to_meter,
      "to_world": proj_transform,
      "fov": fov_proj
  }

nomatter use polarizer or circular;
nomatter put filter before my projector how far between projector and object;
nomatter turn every degree;
nomatter what intensity I set;
the projector's light can't through the filter, the filter: rectangle.obj is a slice, download from official example: meshes/rectangle.obj.

why, help please, I'm gonna cry now.

[guge2]

hello? I found that it's all fine if use area light, but projector or spot light can't walk through glass or polarizer.

[njroussel]

Hi @guge2
Sorry, we're quite busy with other tasks at the moment. I should have more time next week.

[njroussel]

Hello again @guge2

What integrator are you using?
Unless you're using a ptracer or volpath, this behavior is expected. Other integrators do not handle Null BSDFs efficiently during emitter sampling, making it impossible to connect your light path to an emitter.

[guge2]

Hello again @guge2

What integrator are you using? Unless you're using a ptracer or volpath, this behavior is expected. Other integrators do not handle Null BSDFs efficiently during emitter sampling, making it impossible to connect your light path to an emitter.

Thanks for your reply, when I use volpath, projector's light can walk through glass, polarizer, but they just act as a glass, there's no any render of polarization because I can't use volpath and stokes together.
Is it means that: If someone want to simulate a scanner with polarizer, only they can do is to wait for mitsuba3's update? If yes, I'd like to wait, thank you.