This additional panel appears below the Rendered Frame Window when mental ray is the active renderer. It allows for easy adjustment of important settings related to reflection, refraction, final gathering, and more.
Please note: If you change a setting here, the equivalent Render Setup dialog setting updates automatically, but the reverse is not true. If you change a setting on the Render Setup dialog, to see the change on this panel, you must first click the panel to refresh its display.
Provides presets for a number of recommended combinations of minimum and maximum Samples Per Pixel settings. For details, see Samples per Pixel group.
A global multiplier for the Shadow Samples setting in all lights casting soft shadows. This includes all photometric lights (Target Light, Free Light, mr Sky Portal), as well as mr Sun, mr Area Omni, and mr Area Spot. Typically the light should be set to cast ray traced shadows, although in some cases shadow maps work too.
Possible multiplier values are 0.125, 0.25, 0.5, 1, 2, 4, 8, and 16. The leftmost slider position (“Soft Shadows off”) is
equivalent to turning on Area Lights/Shadows as Points. The remaining slider positions are also available as the Global Tuning Parameters rollout 
Soft Shadows Precision control.
For an example, see this illustration.
Provides a range of quick, easy preset solutions for final gathering. The default presets are: Draft, Low, Medium, High, Very High, and Custom (the default choice). Available only when Final Gather is on. For details, see FG Precision Presets.
Controls reflection quality globally and, at the leftmost position, disables all reflections (see Enable Reflections). To improve performance when you don’t require reflections, drag the slider all the way to the left.
At other positions, the slider determines the quality of reflections in all instances of the Arch & Design material and related materials in the scene. The slider setting acts as a multiplier to each material’s Reflection group Glossy Samples setting. For an example, see this illustration.
Glossy Samples settings of 32, 20, and 8, and you set Glossy Reflections Precision to 0.5X (Low), the resultant values as rendered will be 16, 10, and 4. However, the original material settings remain intact, and are restored for rendering purposes when
you set the slider back to 1.0X - Default.
The equivalent Render Setup dialog controls are Glossy Reflections Precision and Enable Reflections.
Controls refraction quality globally and, at the leftmost position, disables all refraction (see Enable Refractions). To improve performance when you don’t require refraction, drag the slider all the way to the left.
At other positions, the slider determines the quality of refractions in all instances of the Arch & Design material and related materials in the scene. The slider setting acts as a multiplier to each material’s Refraction group Glossy Samples setting.
Glossy Samples settings of 32, 20, and 8, and you set Glossy Reflections Precision to 0.5X (Low), the resultant values as rendered will be 16, 10, and 4. However, the original material settings remain intact, and are restored for rendering purposes when
you set the slider back to 1.0X - Default.
The equivalent Render Setup dialog control is Glossy Refractions Precision and Enable Refractions.
Sets the maximum number of times a ray can be reflected. At 0, no reflection occurs. At 1, the ray can be reflected once only. At 2, the ray can be reflected twice, and so on. Default=4.
The equivalent Render Setup dialog control is Max. Reflections.
Sets the maximum number of times a ray can be refracted. At 0, no refraction occurs. At 1, the ray can be refracted once only. At 2, the ray can be refracted twice, and so on. Default=6.
The equivalent Render Setup dialog control is Max. Refractions.
Sets the number of times mental ray calculates diffuse light bounces for each diffuse ray. Default=0.
The equivalent Render Setup dialog control is Diffuse Bounces.
These commands let you save rendering time by reusing translated geometry and final gather solutions. The Final Gather controls are available only when Final Gather is on.
Lock Geometry TranslationDetermines whether changed geometry is retranslated to mental ray format at render time. When on, sub-object-level changes such as vertex editing or adjusting a modifier such as Bend are ignored and don’t cause retranslation. However, object-level changes such as moving or rotating an object are retranslated.
The equivalent Render Setup dialog control is Translator Options rollout Geometry Caching group Lock Geometry Translation.
When on, rendering uses geometry caching. During the first render, the translated geometry is saved to the cache file. Then, in subsequent renderings of the same scene, the renderer uses the cached geometry for any unchanged objects instead of retranslating it. Any changed geometry is retranslated. Default=off.
The equivalent Render Setup dialog control is Translator Options rollout Geometry Caching group Enable.
Clear Geometry CacheThe equivalent Render Setup dialog control is Translator Options rollout Geometry Caching group Clear Geometry Cache.
Lock Final GatherDetermines whether or not mental ray uses the final gather map (FGM) file or files as is. When off, mental ray can add new
final gather points if necessary. When on, mental ray uses only the data in the specified file, and does not generate any
new final gather points during the pre-processing stage. Available only when Reuse Final Gather is on (see following). Default=off.
To create the FGM files, use Generate Final Gather Map Now or the drop-down list next to it (
).
The equivalent Render Setup dialog control is Read FG Points Only from Existing Map Files .
When on and Lock Final Gather is off (see preceding), generates or updates a final gather map (FGM) file. If Lock Final Gather is on as well, mental ray does not perform final gathering, but instead uses cached final gather map data to save rendering time.
If no FGM file is specified on the Render Setup dialog Final Gather rollout (see Final Gather Map group), 3ds Max uses the file name temp.fgm.
The equivalent Render Setup dialog control, when Lock Final Gather is off, is Incrementally Add FG Points to Map Files.
Clear Final Gather CacheDeletes the cached final gather solution.
The equivalent Render Setup dialog control is Reuse rollout Final Gather Map group Delete File.
Choose the result of clicking the Render button:
Use this option when doing quick iterations on the image, usually in parts; for example, working on final gather settings, reflections, or specific objects or areas of the scene.
This choice is also available from a drop-down in the bottom-left corner of the Render Setup dialog. And you can render in either mode from the render flyout on the main toolbar.
