Category Archives: News

NEW: Getting a trial license for Arnold

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To get a trial license, go to the Free Trial page at https://www.autodesk.com/products/arnold/trial-intake

You have to click the Download button. That’s what generates the trial license and adds it to your Autodesk account. But you don’t need that download (it’s the Arnold SDK, not an Arnold plugin), so Cancel that download after it starts.

You can download the Arnold plugin of your choice from arnoldrenderer.com/download.

To use the trial license, install the Arnold plugin and then start the Arnold License Manager and sign in.

Remapping paths at render time!

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New with Arnold 6.0.4 is path mapping.

All you have to do is create a json file that looks something like this:

{
         "windows": { "S:/": "\\server\projects\" },
         "mac": { "S:/": "/Volumes/projects/"},
         "linux": {"S:/": "/mnt/projects/"}
}

and then set ARNOLD_PATHMAP to point to the json path mapping file

How Arnold handles paths

When you render a frame, here’s what Arnold does for file paths:

  1. Replace backslashes

    When Arnold loads an ass file, Arnold replaces all backslashes ( \ ) with forward slashes ( / )

  2. Expand environment variables

    When Arnold uses a parameter, Arnold expands all environment variable references, which look like this: [MY_TEXTURE_PATH]

  3. Map paths

    After Arnold expands environment variables, Arnold applies the path-mapping rules specified by the Arnold pathmap file.

Arnold expands environment variable expansion and maps paths for:

  • search paths in the options node
  • filename parameters for these nodes:
    • alembic
    • color_manager
    • all driver nodes such as driver_deepexr, driver_exr, driver_jpg, driver_png, and driver_tiff
    • image
    • include_graph
    • materialx
    • photometric_light
    • procedural
    • volume
    • volume_implicit

Setting up path mapping

You can automatically remap paths at render time using a pathmap file.

To use a pathmap

  • Set the ARNOLD_PATHMAP environment variable to point a pathmap file

The pathmap file is a json file. For example:

{
         "windows": { "S:/": "\\server\projects\" },
         "mac": { "S:/": "/Volumes/projects/"},
         "linux": {"S:/": "/mnt/projects/"}
}

Path mapping uses regular expressions. The general format of an entry is this:

{
         "windows": { "regular expression": "replacement string" },
}

For example, this pathmap replaces all drive mappings like E:/ and S:/ with //SERVER/

{
         "windows": { "[A-Z]:/": "//SERVER/" },
}

Arnold converts backslashes ( \ ) to forward slashes ( / ) when it loads the ASS file.

Path mapping happens after that, so pathmaps never have to deal with backslashes.

There can be multiple mappings for each OS:

{
         "windows": { "[A-Z]:": "//SERVER", "sourceimages/": "textures/"},
}

Auto-instancing in Arnold 6.0.2

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Controllable auto-instancing on ASS procedurals: You can now disable the default automatic instantiation of procedurals pointing at the same ASS file with the auto_instancing parameter on each procedural or by the procedural_auto_instancing option. This workaround is sometimes useful when overriding procedural parameters with operators.

Arnold 6.0.2 release notes https://docs.arnoldrenderer.com/x/1gGvBg

So, what’s all that mean?

It means that if you load the same ass file many times, Arnold will load the ass file just one time, and then automatically create instances of that. For example, if I load an ass file three times, I will get two instances.

In previous versions, this was known as the procedural cache, and it was a global option. Now it’s called auto_instancing and you can set it on each procedural node (aka aiStandin in Maya).

In general, you want auto instancing, because instancing is more efficient than loading the same ass file over and over. But if you’re using operators to apply different looks to the same procedural, you need to turn off auto instancing. Otherwise all the procedurals will have the same look (because they all be instances of the same one procedural).

For example, with auto instancing on, I get this, even though I’ve assigned different looks to each procedural (standin):

Everything has the same look with auto instancing on

I can also tell from the Arnold log that I’m getting instances. Note that 2 are reused

| ---------------------------------------------------------
| ass file cache           
|   unique (loaded from disk)              1 (33.33%) 
|   reused (found in cache)                2 (66.67%) 
|   total referenced .ass files            3 (100.00%) 
| ---------------------------------------------------------

If I turn off auto instancing (in the procedural parameters)

then I get three different looks

In the Arnold log, that looks like this (0 reused means 0 instances)

| ---------------------------------------------------------
| ass file cache
| unique (loaded from disk) 1 (100.00%)
| reused (found in cache) 0 (0.00%)
| total referenced .ass files 1 (100.00%)
| ---------------------------------------------------------

Using an operator to override parameters in an ass file

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Arnold 5.1 adds operators, which among other things, allow you to override parameters in ass files loaded by procedural nodes.

Here’s a quick example using the brand new MtoA 3.0

I exported some particles from Softimage, loaded them into Maya with an aiStandin (aka an Arnold procedural), and then used a set_parameter operator to scale the radius by 0.5

Note that I connect my operator by setting the Target Operator in the Render Settings.
set_parameter_radius
I can chain two set_parameter operators together, to set the mode and then scale the radius:
set_parameter_mode_radius

SItoA is open-sourced

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First, here’s some Arnold renders of a few old-time Softimage models:

And now, here’s the announcement:

Softimage to Arnold (or SItoA), the Arnold plugin for Autodesk Softimage is being made available to the community under an Apache2.0 open source license at:

https://github.com/Autodesk/sitoa

This repository contains the official SItoA plugin source code. Solid Angle, the company behind the Arnold renderer, and now part of Autodesk, developed the SItoA plugin commercially from 2009 to 2017.

After the Softimage end-of-life announcement in April 2014, Solid Angle committed to continue the development and maintenance of SItoA for at least a year, and then extended this period until July 2017, porting SItoA to the new Arnold 5 API along the way.

Governance
 

Please submit your issues and pull requests on github, the old Trac server will remain available for a while as read-only but we won’t accept any new users.

We will continue to monitor and review pull requests submitted to this repo on a voluntary basis, but will not release official builds any more.

Acknowledgments

Before it was open-sourced, throughout the years, SItoA has been developed by:

  • Luis Armengol
  • Borja Morales
  • Stefano Jannuzzo

With contributions by:

  • Andreas Bystrom
  • Steven Caron
  • Julien Dubuisson
  • Steffen Dunner
  • Michael Heberlein
  • Paul Hudson
  • Halfdan Ingvarsson
  • Vladimir Jankijevic
  • Alan Jones
  • Guillaume Laforge
  • Thomas Mansencal
  • Helge Mathee
  • Eric Mootz
  • Holger Schoenberger
  • Frederic Servant
  • Jules Stevenson

Special thanks to all the users who passionately provided feedback, production assets, bug reports and suggested features during those years.

Solid Angle’s New Website

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The minimalist solidangle.com is gone. Check out our new web site:

  1. Read the latest Arnold news.
  2. Download and try the latest versions of Arnold for Maya and Softimage.
  3. Check out the Customer gallery and see the amazing work that our users have creating with Arnold. Feel free to participate: send us your amazing Arnold renders.
  4. Learn the technology behind Arnold in the past white papers on our Arnold Research section.

Plus plenty, plenty more. Arnold is no longer in the dark, so come and see what it’s all about.