Here’s a way to use standins with MASH dynamics: instance a low-poly mesh that has its Arnold Translator set to procedural.
I have another, more general, version of this post here. This one is for new Arnold users with Maya 2017.
Here’s what to do if you get errors like this:
// Error: file: C:/Program Files/Autodesk/Maya2017/scripts/startup/autoLoadPlugin.mel line 32: Unable to dynamically load : C:/solidangle/mtoadeploy/2017/plug-ins/mtoa.mll The specified module could not be found. // // Error: file: C:/Program Files/Autodesk/Maya2017/scripts/startup/autoLoadPlugin.mel line 32: The specified module could not be found.
As of Arnold 4.2.16.2, the SSE requirement is now SSE4.1
If this is the first time you’ve tried to use the Maya to Arnold (MtoA) plugin, then check whether your processor supports SSE4.1.
If MtoA used to load, but now it doesn’t, then something happened to the MtoA installation. I’ve seen several cases where DLLs were missing from the MtoA bin folder; most importantly, Arnold itself was missing (Arnold is ai.dll on Windows, or libai.so on Linux, or libai.dylib on OSX).
If you make a backup copy of the MtoA install folder, we can investigate after you fix things by installing MtoA.
If a clean install of MtoA doesn’t work (and the computer does support SSE4.1), then “The specified module could not be found.” usually means there’s a missing dependency. Dependency Walker is a decent, if aging, tool for checking out dependencies, but for leaving no stone unturned, I prefer Process Monitor.
The MtoA plugin (mtoa.mll) depends on a handful of files only. Here’s the log of loaded DLLs for a working MtoA:
Here’s a quick walkthrough (no audio) of how to get a Process Monitor log:
You may have noticed the Force Translate Shading Engine option in the export dialog (or in the Feature Overrides section of the Render Settings).
Force Translate Shading Engines forces MtoA to export shape nodes with a shader link, like this:
polymesh
{
...
shader "aiStandard1SG"
declare mtoa_shading_groups constant ARRAY NODE
mtoa_shading_groups "aiStandard1SG"
}
where “aiStandard1SG” is the name of a MayaShadingEngine shader node.
This allows you to keep your shapes and shaders in separate ASS files. For example, you could have one standin that loads the shapes, and a second standin that loads the shaders. As long as the shape nodes include links to the shaders, Arnold will resolve the links and render the shapes with the right shaders.
For the render -rt 1 command, you can specify the output ASS name in
the defaultArnoldRenderOptions.output_ass_filename attribute. For example:
set PRE_RENDER_MEL="setAttr -type \"string\" defaultArnoldRenderOptions.output_ass_filename \"c:/Users/StephenBlair/Documents/example\";" render -s 6 -e 8 -r arnold -rt 1 -preRender %PRE_RENDER_MEL% C:\projects\Support\scenes\_2016\XSI_deformed_logo.mb
This will export ASS files named “example.ass”.
The scene should have the Frame/Animation ext set to something like
“name.#.ext”. Otherwise, if it is “name.ext” you’ll get filenames like
“example.ass.0004.ass”
output_ass_filename can have environment variables, but you have to be
careful to use forward slashes. For example:
set PRE_RENDER_MEL="setAttr -type \"string\" defaultArnoldRenderOptions.output_ass_filename \"%OUTPUT_ASS_FILENAME%\";" set OUTPUT_ASS_FILENAME=C:/Users/StephenBlair/Documents/example render -s 6 -e 8 -r arnold -rt 1 -preRender %PRE_RENDER_MEL% C:\projects\Support\scenes\_2016\XSI_deformed_logo.mb
There’s also the arnoldExportASS command, if you want to script the export.
maya -batch -file scene.mb -command "arnoldExportAss -f "/home/blairs/Desktop/example.ass" -mask 255 -lightLinks 1 -compressed -shadowLinks 2 -cam sideShape;"
The Arnold log is important, not just for troubleshooting and getting help from us at Solid Angle, but also for understanding what’s going on when Arnold renders your scene.
To get an Arnold log:
For batch rendering, Arnold log messages go into mayaRenderLog.
If you have both Renderman and MtoA installed, you may see a warning that says “Arnold for Maya degrades Renderman performance.” Unless you are running a version of MtoA from 20 months ago, this performance warning is false. MtoA does not degrade Renderman performance.
This was fixed in Arnold 4.2.3.1 (fix #4393 main thread was pinned to a single core) back in January 2015.
There’s an Arnold error that recommends setting the load_at_init parameter, but people don’t always know where to find that in their favorite Arnold plugin.
ERROR| [proc] c4d|Arnold_Procedural: bounds supplied to procedural node are not large enough to contain the actual underlying geometry. Replace given bounds: (-1, -1, -1) X (1, 1, 1), with: (-9.4028616, -9.43616867, -9.21633244) X (9.3304739, 9.43616867, 9.21633244). Setting the procedural's load_at_init parameter to true would also fix this.
The load_at_init parameter controls whether the procedural (standin) is loaded during scene intialization (before rendering starts), or during rendering (when a ray hits the procedural bounding box).
By default, load_at_init is false, which means that procedural loading is deferred until render time.
And so, in MtoA, C4DtoA, and SItoA, the load_at_init parameter is exposed as Defer Standin Load, which is enabled by default. In HtoA, you have a Load At Init parameter on for the Arnold Procedural node.
I woke up this morning and my MtoA was gone 😉
It turned out that mtoa.mll, ai.dll, and all the other DLLs were gone from the MtoA installation directory. How’d that happen? Probably when my computer had a critical Kernel Power error at 4:30am and crashed.
The C4DtoA installer puts the C4DtoA plugin in the default location: the plugins folder of the Cinema 4D install.
If you want to put C4DtoA somewhere else, like a shared network location, you can use the C4D_PLUGINS_DIR environment variable to point to your custom plugin location.
For example, on Windows I moved C4DtoA to a different drive and then set my environment like this:
set C4D_PLUGINS_DIR=F:\plugins set PATH=F:/plugins/C4DtoA/arnold/bin;%PATH%
Note that I had to set PATH so C4D could find ai.dll, and that I had to use forward slashes (on Windows, C4D doesn’t like backslashes in the PATH and drops them).
On Windows, the C4DtoA installer puts a second copy of ai.dll in the C:\Program Files\MAXON\CINEMA 4D R17, so you’ll have to remove that ai.dll, and use PATH to point to the ai.dll in the C4DtoA arnold/bin folder.
You can make your ASS files portable across different platforms by using relative paths and the texture search path. For example, if all textures are specified by relative paths like “textures/noicon.tx”, then you just have to set options.texture_searchpath to specify the location of the textures folder.
For example
kick -set options.texture_searchpath //server/project/ -dp -dw example.ass
Or if the texture search path is set to an environment variable
export ARNOLD_TEXTURE_PATH=//server/project ./kick example.ass
To use relative paths for texture file names in nodes like MayaFile, aiImage, aiPhotometricLight, and aiSkydomeLight, you just need to do the following:
You can put multiple locations, using either : or ; to separate the paths (Arnold supports both separators on all platforms: OSX, Linux, and Windows)
You can use environment variables by putting the environment variable name in square brackets. For example:
"[ARNOLD_TEXTURE_PATH]:C:/Assets/IES/;C:/maya/projects/Support/sourceimages"
Forward slashes work on all platforms.
MtoA appends the current project’s sourceimages folder to the texture search path.
Arnold Support Corner 