I'm probably missing a simple thing here but I cannot remove reflection from materials that should not be reflecting.
Example - I have a cementitious (cement based, rough textured, non-reflective) surface finish on a wall. It is currently reflecting objects and material that are nearby. The reflectivity of the material is set to zero though. How can it still be reflecting? (see the headboard in the attached image. Same problem with the fabric on the bed)
Switching off my single reflection probe (even though it's not transitioning that far) doesn't help.
Here's another example - same project. These cabinet doors are modelled identically, imported identically and have the same material applied. However 3 doors shows reflection plus the drawer, while the other doors do not show nearly as much reflection. FYI the material shown here is the material that is imported. Once using a TM material the reflection problem does not improve. If I use another material from the 3rd party modelling app (SketchUp), these 3 doors still arrive with this reflection problem.
OK, so I remodelled all affected objects / meshes and the reflection problem is fixed. My very simplified conclusion is that something happens to UV's in SketchUp when the "Scale" tool is used to transform objects. Not sure how this would affect reflection specifically though. It seems the SU to TM transfer prefers pure modelling and no shortcuts.
Thanks to @Morgan Crockett who pointed out that the model had a translucent glass material applied to the reverse face of meshes inside SU. By changing the reverse face material inside SU or using the "Apply to Object" tool inside TM the reflection problem was solved without having to re-model anything.