how to access vray render settings?

Here is a list in case you don't get anything in the listener:

showproperties vr
  .imageSampler_type : integer
  .filter_on : boolean
  .filter_kernel : maxObject
  .filter_size : float
  .filter_paramA : float
  .filter_paramB : float
  .filter_paramC : float
  .fixedRate_subdivs : integer
  .fixedRate_rand : boolean
  .twoLevel_baseSubdivs : integer
  .twoLevel_fineSubdivs : integer
  .twoLevel_showSamples : boolean
  .twoLevel_useDMCSamplerThresh (twoLevel_useMCSamplerThresh) : boolean
  .twoLevel_threshold : float
  .adaptiveSubdivision_minRate : integer
  .adaptiveSubdivision_maxRate : integer
  .adaptiveSubdivision_threshold : float
  .adaptiveSubdivision_rand : boolean
  .adaptiveSubdivision_showSamples : boolean
  .imageSampler_outline : boolean
  .imageSampler_mtlID : boolean
  .imageSampler_normal : boolean
  .imageSamper_normal_threshold : float
  .imageSampler_zvalue : boolean
  .imageSampler_zvalue_threshold : float
  .gi_on : boolean
  .gi_refractCaustics : boolean
  .gi_reflectCaustics : boolean
  .gi_primary_type : integer
  .gi_primary_multiplier : float
  .gi_secondary_type : integer
  .gi_secondary_multiplier : float
  .gi_saturation : float
  .gi_contrast : float
  .gi_contrast_base : float
  .gi_saveMapsPerFrame : boolean
  .gi_ao_on : boolean
  .gi_ao_amount : float
  .gi_ao_radius : worldUnits
  .gi_ao_subdivs : integer
  .gi_rayDistanceOn : boolean
  .gi_rayDistance : float
  .gi_irradmap_minRate : integer
  .gi_irradmap_maxRate : integer
  .gi_irradmap_subdivs : integer
  .gi_irradmap_interpSamples : integer
  .gi_irradmap_colorThreshold : float
  .gi_irradmap_normalThreshold : float
  .gi_irradmap_distThreshold : float
  .gi_irradmap_showSamples : boolean
  .gi_irradmap_showCalcPhase : boolean
  .gi_irradmap_showDirectLight : boolean
  .gi_irradmap_preset : integer
  .adv_irradmap_interpolationType : integer
  .adv_irradmap_mode : integer
  .adv_irradmap_dontDelete : boolean
  .adv_irradmap_loadFileName : filename
  .adv_irradmap_saveFileName : filename
  .adv_irradmap_calcInterpSamples : integer
  .adv_irradmap_useCurrentPassSamples : boolean
  .adv_irradmap_autoSave : boolean
  .adv_irradmap_autoSaveFileName : filename
  .adv_irradmap_switchToSavedMap : boolean
  .adv_irradmap_randomize : boolean
  .adv_irradmap_lookupType : integer
  .adv_irradmap_checkSampleVisibility : boolean
  .adv_irradmap_limitSearchRange : boolean
  .gi_irradmap_multipleViews : boolean
  .gi_irradmap_blurGI : float
  .gi_irradmap_detail_on (irradmap_detail_on) : boolean
  .gi_irradmap_detail_radius (irradmap_detail_radius) : float
  .gi_irradmap_detail_subdivsMult (irradmap_detail_subdivsMult) : float
  .gi_irradmap_detail_scale (irradmap_detail_scale) : integer
  .gi_irradmap_previewMode (irradmap_previewMode) : integer
  .gi_irradmap_interpFrames : integer
  .caustics_on : boolean
  .caustics_searchDist : worldUnits
  .caustics_maxPhotons : integer
  .caustics_multiplier : float
  .caustics_mode : integer
  .caustics_dontDelete : boolean
  .caustics_loadFileName : filename
  .caustics_saveFileName : filename
  .casutics_autoSave : boolean
  .caustics_autoSaveFileName : filename
  .caustics_switchToSavedMap : boolean
  .caustics_maxDensity (caustics_maxDens) : worldUnits
  .caustics_showCalcPhase : boolean
  .environment_gi_on : boolean
  .environment_gi_color : RGB color
  .environment_gi_color_multiplier : float
  .environment_gi_map : texturemap
  .environment_gi_map_on : boolean
  .environment_rr_on : boolean
  .environment_rr_color : RGB color
  .environment_rr_color_multiplier : float
  .environment_rr_map : texturemap
  .environment_rr_map_on : boolean
  .environment_refract_on : boolean
  .environment_refract_color : RGB color
  .environment_refract_color_multiplier : float
  .environment_refract_map : texturemap
  .environment_refract_map_on : boolean
  .gbuffer_channelMask : integer
  .colorMapping_type : integer
  .colorMapping_darkMult : float
  .colorMapping_brightMult : float
  .colorMapping_gamma : float
  .colorMapping_affectBackground : boolean
  .colorMapping_clampOutput : boolean
  .colorMapping_clampLevel : float
  .colorMapping_subpixel : boolean
  .colorMapping_adaptationOnly : boolean
  .colorMapping_linearWorkflow : boolean
  .camera_type : integer
  .camera_overrideFOV : boolean
  .camera_fov : float
  .camera_cyl_height : float
  .camera_fish_autoDistance : boolean
  .camera_fish_distance : float
  .camera_fish_curve : float
  .dof_on : boolean
  .dof_distance : worldUnits
  .dof_getFromCamera : boolean
  .dof_shutter : worldUnits
  .dof_subdivs : integer
  .dof_bias : float
  .dof_sides_on : boolean
  .dof_sides_num : integer
  .dof_sides_rotation : angle
  .dof_anisotropy : float
  .moblur_on : boolean
  .camera_motion_blur : boolean
  .moblur_duration : float
  .moblur_intervalCenter : float
  .moblur_geomSamples : integer
  .moblur_prepassSamples : integer
  .moblur_dmc_minSamples (moblur_minSamples) : integer
  .moblur_geometryParticles : boolean
  .moblur_bias : float
  .system_distributedRender : boolean
  .system_raycaster_maxLevels : integer
  .system_raycaster_minLeafSize : worldUnits
  .system_raycaster_faceLevelCoeff : float
  .system_raycaster_memLimit : integer
  .system_instancedObjects : integer
  .system_raycaster_optLevel : integer
  .system_region_x : integer
  .system_region_y : integer
  .system_region_meaning : integer
  .system_region_sequence : integer
  .system_region_sequence_reverse : integer
  .system_previousRender : integer
  .system_region_lockSize : boolean
  .system_frameStamp_on : boolean
  .system_frameStamp_string : string
  .system_frameStamp_fullWidth : boolean
  .system_frameStamp_justify : integer
  .system_workInCameraSpace : boolean
  .system_checkForMissingFiles : boolean
  .system_optimizedAtmospherics : boolean
  .system_lowThreadPriority : boolean
  .system_vrayLog_show : boolean
  .system_vrayLog_level : integer
  .system_vrayLog_file : filename
  .system_vrayLog_ccToDebugger : boolean
  .system_numThreads : integer
  .dmc_timeDependent (mc_lockToPixels) : boolean
  .dmc_importanceSampling (mc_importanceSampling) : float
  .dmc_earlyTermination_amount (mc_earlyTermination_amount) : float
  .dmc_earlyTermination_threshold (mc_earlyTermination_threshold) : float
  .dmc_earlyTermination_minSamples (mc_earlyTermination_minSamples) : integer
  .dmc_subdivs_mult (mc_subdivs_mult) : float
  .dmc_pathSampler_type (mc_pathSampler_type) : integer
  .photonMap_bounces : integer
  .photonMap_searchDist : worldUnits
  .photonMap_autoDist : boolean
  .photonMap_maxPhotons : integer
  .photonMap_convert : boolean
  .photonMap_interpSamples : integer
  .photonMap_multiplier : float
  .photonMap_convexHullEstimate : boolean
  .photonMap_storeDirectLight : boolean
  .photonMap_retraceCorners : float
  .photonMap_retraceBounces : integer
  .photonMap_maxDensity : worldUnits
  .photonMap_mode : integer
  .photonMap_loadFileName : filename
  .photonMap_saveFileName : filename
  .photonMap_dontDelete : boolean
  .photonMap_autoSave : boolean
  .photonMap_autoSaveFileName : filename
  .photonMap_switchToSavedMap : boolean
  .photonMap_showCalcPhase : boolean
  .options_displacement : boolean
  .options_lights : boolean
  .options_hiddenLights : boolean
  .options_shadows : boolean
  .options_defaultLights : integer
  .options_reflectionRefraction : boolean
  .options_limitDepth : boolean
  .options_maxDepth : integer
  .options_maps : boolean
  .options_filterMaps : boolean
  .options_transpMaxLevels : integer
  .options_transpCutoff : float
  .options_dontRenderImage : boolean
  .options_overrideMtl_on : boolean
  .options_overrideMtl_mtl : material
  .options_showGIOnly : boolean
  .options_ray_bias : float
  .options_glossyEffects : boolean
  .options_geom_backfaceCull : boolean
  .options_mtl_filterMaps_indirect : boolean
  .options_useLegacyModels : boolean
  .options_use3dsMaxPhotometricUnits : boolean
  .output_on : boolean
  .output_aspectlock (Lock_aspect) : boolean
  .output_imageaspect (Image_aspect) : float
  .output_width : integer
  .output_height : integer
  .output_aspect : float
  .output_fileOnly : boolean
  .output_saveFile : boolean
  .output_fileName : string
  .output_saveRawFile : boolean
  .output_rawFileName : filename
  .output_useram : boolean
  .output_genpreview (output_genrpeview) : boolean
  .output_splitgbuffer : boolean
  .output_splitfilename : filename
  .output_splitbitmap : bitmap
  .output_getsetsfrommax : boolean
  .output_splitRGB : boolean
  .output_splitAlpha : boolean
  .output_renderType : integer
  .output_regxmin : integer
  .output_regxmax : integer
  .output_regymin : integer
  .output_regymax : integer
  .output_force32bit_3dsmax_vfb : boolean
  .output_rawExrUseHalf : boolean
  .displacement_overrideMax : boolean
  .displacement_edgeLength : float
  .displacement_viewDependent : boolean
  .displacement_maxSubdivs : integer
  .displacement_tightBounds : boolean
  .displacement_amount : float
  .displacement_relative : boolean
  .dmcgi_subdivs (mcgi_subdivs) : integer
  .dmcgi_depth (mcgi_depth) : integer
  .lightcache_subdivs : integer
  .lightcache_sampleSize : float
  .lightcache_filter_type : integer
  .lightcache_filter_size : float
  .lightcache_bounces : integer
  .lightcache_showCalcPhase : integer
  .lightcache_storeDirectLight : integer
  .lightcache_multipleViews : boolean
  .lightcache_scale : integer
  .lightcache_mode : integer
  .lightcache_retrace_on : boolean
  .lightcache_retrace_threshold : float
  .lightcache_loadFileName : filename
  .lightcache_saveFileName : filename
  .lightcache_interpSamples : integer
  .lightcache_prefilter_on : boolean
  .lightcache_prefilter_samples : integer
  .lightcache_dontDelete : boolean
  .lightcache_autoSave : boolean
  .lightcache_autoSaveFileName : filename
  .lightcache_switchToSavedMap : boolean
  .lightcache_useForGlossyRays : boolean
  .lightcache_numPasses : integer
  .lightcache_adaptiveTracing : boolean
  .lightcache_adaptiveTracing_dirsOnly (lightcahe_adaptiveTracing_dirsOnly) : boolean
  .lightcache_minPathsPerSample : integer
  .excludeListOverrideMtl : node array
  .includeListOverrideMtl : node array