Is it possible to add a cone actor together with a volume actor

const actor = imageDataToVol3D(image_data_obj);
const actor_cone = vtkActor.newInstance();

If I enable both addActor() calls only the image data actor shows up. Is it possible to do so?

To add a volume, you should call addVolume instead of addActor.

thanks for pointing out this. Changed the call to addVolume and the result is the same.
the code works fine when only one of renderer.add() is called, when both are called, the cone will not show up, only the volume shows

Are you calling resetCamera after adding your actors? And is your volume opaque, potentially hiding your cone?

Thanks for the tip. After enlarging the cone 30 times bigger I can see it together with the volume.