Rendering menu > Render > Render Scene dialog > Processing panel > Translator Options rollout
Main toolbar > Render Scene > Render Scene dialog > Processing panel > Translator Options rollout
Note: The Processing panel appears only when the mental ray renderer is the currently active renderer.
Controls in this rollout affect the general operation of the mental ray renderer. They also control the mental ray translator, which can save to an MI file. The translation is in mental ray version 3 (mi3) format. The translator does not support mental ray version 1 (mi1).
To create a rendering from multiple passes:
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Use the Render Type > Selected option to choose only a portion of the scene to render.
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On the Translator Options rollout, in the Render Passes group, click the ellipsis [...] button next to Save.
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A Save As dialog is displayed. Use it to enter a name and location for the PASS file.
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The partial rendering is saved in the PASS file you specified.
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Repeat steps 1 through 4 until you have generated all the passes for the rendering (or all the passes but the last).
Warning: If your scene includes an environment, render it only in the final pass. Rendering the environment in multiple passes is time consuming, and can lead to artifacts such as unwanted color changes to the background. Render all passes but the last one using a default black background.
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In the Render Passes group, click Add to add the various pass files to the list.
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At this point, you might also want to turn off Save, unless you want the final result to be saved as a PASS file as well as a rendering.
Tip: For some purposes, you might want to create the passes, then create a new Autodesk VIZ scene with no objects, set the rendering resolution to match the passes, you created, then merge the passes as described in steps 7 and 8 above.
Use Placeholder Objects—When on, geometry is sent to the mental ray renderer only on demand. Initially, the mental ray scene database is populated only with the size (bounding box) and position of objects in the Autodesk VIZ scene. When the mental ray renderer renders a bucket that contains an object, the object's geometry is sent to the rendering engine only at that point. Default=off.
This option can improve rendering speed when a large amount of the scene's geometry is outside of the view you are rendering.
Tip: When you use placeholders, always calculate buckets in Hilbert order. See Sampling Quality Rollout (mental ray Renderer).
When the mental ray renderer is low on memory (as defined by the Memory Limit setting), Use Placeholder Objects enables it to increase available memory by deleting object geometry from the scene database. This can dramatically reduce memory usage, but with a possible cost in rendering speed.
Memory Limit—The mental ray renderer keeps a count of the memory it uses at render time. If it reaches the memory limit and Use Placeholder Objects is on, the geometry for some objects will be discarded in order to allocate memory for other objects. If Use Placeholder Objects is off, or if after deleting geometry more memory is still needed, the renderer releases texture-map memory as well. Default=1024 MB.
Use mental ray Map Manager—When on, maps are read from disk and if necessary, translated to a format that the mental ray renderer can read. When off, maps are accessed directly from memory, and translation is unnecessary. Default=off.
Following is a complete list of differences between turning this option on and off:
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mental ray reads textures directly from disk (mental ray is able to flush textures out of memory when memory is low). Also, textures are loaded only if needed.
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mental ray uses its built-in pyramid filtering system. These pyramid lookup tables can be flushed out of memory when memory is low.
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Texture formats not supported directly by mental ray are read by Autodesk VIZ and sent, before rendering begins, as binary data to mental ray.
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Autodesk VIZ reads the textures from disk, and then sends individual pixel colors to mental ray as they are needed.
Note: Autodesk VIZ reads the textures from disk and keeps them stored in memory between renders. This can make renders faster, because the bitmaps don’t need to be reloaded every time. Autodesk VIZ will not read the texture from disk if it was already loaded previously (for example, in a previous render, for a Material Editor preview, or for displaying the map in a viewport).
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Rendering uses a pyramid filter shader that is identical to the standard Autodesk VIZ pyramid filter system.
Turning this option on is useful for large scenes that take a lot of memory to render. Turning it off is quicker, because textures already loaded in memory don’t have to be reloaded by mental ray. But turning it off might use more memory and doesn’t allow for flushing when memory is low, unless you use the Autodesk VIZ bitmap pager.
Note: Turning the option on and off might result in very small differences between rendered images because of the different algorithms used in the mental ray map manager and the Autodesk VIZ map manager.
You must turn on “Use mental ray Map Manager” when performing these actions:
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Using distributed bucket rendering.
See Distributed Bucket Rendering Rollout (mental ray Renderer).
When rendered with distributed bucket rendering and the mental ray map manager, images with textures can look different than when rendered with Autodesk VIZ alone, because the filtering technique is different.
Conserve Memory—Tells the translator to be as memory efficient as it can. This can slow down the translation process, but reduces the amount of data being sent to the mental ray renderer. Default=off.
This option is useful when you are trying to render a huge scene and time is not necessarily an issue. When you render to an MI file, this option can also help reduce the size of the output file.
When on, this toggle also tells the mental ray renderer to save frames as temporary .map files. This allows you to render extremely large frames without running out of random-access memory.
The location of the temporary map files is chosen in the following order:
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If the file \[program folder]\mentalray\rayrc contains a registry entry called _MI_REG_FBDIR, the renderer uses this directory.
The entry should have the form
registry "{_MI_REG_FBDIR}" value "<path>" end registry -
If the rayrc file has no registry entry, the renderer uses the directory specified by the TMPDIR environment variable.
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If there is no TMPDIR environment variable, the renderer uses the directory specified by the TEMP environment variable.
Material Override allows you to render a scene with all its materials replaced by a single master material. For example, if you need to do a wireframe pass, you can create a Wire material and then specify it here. When you render, all surfaces will use the Wire material.
Enable—When on, rendering uses the override material for all surfaces. When off, surfaces are rendered with the material applied to them in the scene. Default=off.
Material—Click to display the Material/Map Browser and choose a material to use as the override. Once you have chosen an override material, this button displays the material name.
These controls let you save the translated scene in a mental ray MI file.
Note: Exporting to an MI file is not available when you render to texture.
Export on Render—When on, saves the translated file to an MI file. Turn off to avoid saving the translated scene. Save is available only when you have clicked Files to specify an MI file. Default=off.
Un-compressed—When on, the MI file is not compressed. When off, the file is saved in a compressed format. Default=on.
Incremental (Single File)—When on, an animation is rendered as a single MI file that contains a definition of the first frame and descriptors of the incremental changes from frame to frame. When off, each frame is rendered as a separate MI file. Default=off.
When you render an animation, turning on Incremental can save a considerable amount of disk space.
Controls in this group let you create a rendering out of multiple passes that render portions a scene. This can be a useful way to render large scenes or scenes that have complex effects. It can also be a way to divide the labor on a composited (“merged”) rendering. See the “Procedures” section, above, for more information.
Note: You cannot render to passes when you render to texture.
Save—When on, saves the image currently being rendered (prior to merging) inside the specified PASS file.
If you are rendering a time segment (that is, an animation), the PASS files are created with sequence numbers appended to the main file name (for example, test0000.pass, test0001.pass, and so on).
Merge—When on, the PASS files specified in the list will be merged into the final rendering.
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List of PASS files—Lists the PASS files that will be merged into the final rendering (possibly including the pass that is currently being rendered and saved).
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Add—Click to add a PASS file to the list.
If you choose a PASS file with a sequence number appended to its name, Autodesk VIZ asks if you want to use the individual file or the entire sequence.
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Delete—Click to delete the highlighted PASS file from the list.
Merge Shader—Lets you choose the shader used to merge the PASS files. Clicking the shader button displays a Material/Map Browser so you can choose the shader (when a shader is chosen, its name appears on the button). When the toggle is on, this shader is used for merging.
Important: No merge shaders are provided with Autodesk VIZ. This option is provided for users who plan to write a custom merge shader appropriate to their particular compositing project.
This toggle is for when you are rendering separate elements.
Render Final Image—When on, renders a final, “beauty” pass in addition to the separate elements. When off, renders only the elements. Default=off.