I have the following which appears to work but the setting changes back.

I am trying to turn off reflectivity for photoview renderings.

Option Explicit

Dim swApp As SldWorks.SldWorks

Dim swModel As SldWorks.ModelDoc2

Dim swModelDocExt As SldWorks.ModelDocExtension

Dim swSelMgr As SldWorks.SelectionMgr

Dim swRenderMaterial As SldWorks.RenderMaterial

Dim varRenderMaterial As Variant

Dim vRenderMaterial As Variant

Dim nCount As Long, nId As Long

Dim VConFIGnames As Variant

Sub main()

Set swApp = Application.SldWorks

        Set swModel = swApp.ActiveDoc

        Set swSelMgr = swModel.SelectionManager

        Set swModelDocExt = swModel.Extension

        VConFIGnames = swModel.GetConfigurationNames

        nCount = swModelDocExt.GetRenderMaterialsCount

        'Debug.Print nCount

        varRenderMaterial = swModelDocExt.GetRenderMaterials

For Each vRenderMaterial In varRenderMaterial

    Set swRenderMaterial = vRenderMaterial

    Debug.Print "before  " & swRenderMaterial.Reflectivity

    swRenderMaterial.Reflectivity = 0#

    swModelDocExt.UpdateRenderMaterialsInSceneGraph True

    Debug.Print "after " & swRenderMaterial.Reflectivity

Next

swModel.ForceRebuild3 True

End Sub