[SItoA] Subdivision settings for polygon meshes

To show you where the polygon mesh subdivision settings are in Softimage, I’m going to start in Arnold and work back into Softimage via SItoA.

So, let’s start with an Arnold polymesh shape, which has a number of subdivision parameters:

C:\solidangle\Arnold-\bin>kick -info polymesh | find "subdiv"
ENUM          subdiv_type                       none
BYTE          subdiv_iterations                 1
FLOAT         subdiv_pixel_error                0
NODE          subdiv_dicing_camera              (null)
ENUM          subdiv_adaptive_metric            auto
ENUM          subdiv_uv_smoothing               pin_corners
BOOL          subdiv_smooth_derivs              false

In Softimage, you access most of these subdivison parameters by adding an Arnold Parameters property to a polygon mesh (you can’t add new parameters to Softimage built-in objects like a PolygonMesh, so we have to use a custom property).

  • subdiv_iterations
  • subdiv_pixel_error
  • subdiv_adaptive_metric
  • subdiv_smooth_derivs (Shape group)

Other Arnold subdiv parameters are mapped to existing Softimage parameters:

  • subdiv_uv_smoothing is mapped to Smooth when subdividing in the
    Texture Projection Property Editor. If Smooth when subdividing is enabled, then subdiv_uv_smoothing is set to pin_corners; otherwise, it’s set to linear.
  • subdiv_type is mapped to the Subdivision Rule list in the Polygon Mesh property editor. Linear goes to linear, and anything else (XSI-Doo-Sabin, Catmull-Clark) goes to catclark.

Finally, subdiv_dicing_camera is on the Subdivision tab of the global Render Settings.

[Arnold] Gamma and linear input data

Arnold has three global settings for linearizing input data by applying an inverse-gamma correction. By default, texture maps, light colors, and shader colors are assumed to be already linear, but if you need to linearize them, set the gammas to 2.2.

C:\solidangle\Arnold-\bin>kick -info options | find "gamma"
FLOAT         texture_gamma                     1
FLOAT         light_gamma                       1
FLOAT         shader_gamma                      1


  • The texture_gamma applies only to non-floating point textures. Floating point (Half, Float) textures are assumed linear.
  • Texture maps used to control things like normals, displacement, and opacity, will also be linearized if you set texture_gamma to 2.2.
  • The light and shader gammas apply to colors picked from color swatches in the application UI (that is, color ports that don’t have a shader tree plugged into them).

In plugins like SItoA and MtoA, you can find these gamma settings in the global render options.

I guess I should mention that in Softimage, you could use the built-in color management and leave these all set to 1.

[MtoA] Deadline and MtoA 1.0.x

Update: Deadline 6.1 and later support MtoA 1.0.x

Recently I discovered that Deadline 6.0 doesn’t work with MtoA 1.0.x, and it’s because of a change to the MtoA verbosity levels controls in the Render Settings UI. I think an update for Deadline will soon take care of this problem.

This is the error that stops everything:

0: WARNING: Strict error checking on, ignoring the following unrecognized error or warning. If it is fatal, please email support@thinkboxsoftware.com with the error message.
0: STDOUT: Error: No object matches name: defaultArnoldRenderOptions.log_console_verbosity

At first, I “ignored” that error in the log, but after I eliminated all other possible causes, I came back to it.

I worked around it by editing the default MayaBatch.py file in the DeadlineRepository (on my machine, that’s here: C:\DeadlineRepository6\plugins\MayaBatch\MayaBatch.py).

Go to lines 910, 911, and 912, and change lines 911 and 912 to look like this:

elif self.Renderer == "arnold" or self.Renderer == "arnoldexport":
self.Verbosity = self.GetPluginInfoEntryWithDefault( "ArnoldVerbose", "2" )
return 'removeRenderLayerAdjustmentAndUnlock defaultArnoldRenderOptions.log_verbosity; catch(`setAttr defaultArnoldRenderOptions.log_verbosity ' + self.Verbosity + '`);'

When you submit a job, make sure you set the Arnold verbosity level to 0, 1, or 2. Nothing higher.

[SItoA] Uninstalling SItoA

When you install an addon like SItoA, you may see an error like this the next time you start Softimage:

// ERROR : 2356 - This plug-in is not installed: ArnoldRenderPreferences

That’s because addons like SItoA install custom preferences, which are left behind when you uninstall the addon. At startup, Softimage finds the custom preference but can’t find the plugin that owns the preference (because it’s been uninstalled).

To get rid of this error, go to your Softimage user folder, and delete the Data\Preferences\Arnold Render.preset file.