3ds Max 2020.1 Regression Affecting Krakatoa MX 2.9 PRT Loader (plus solution)


A customer reported an issue with the Krakatoa MX 2.9 PRT Loader not showing controls in the Modify panel. This appears to be a regression in 3ds Max 2020.1 itself – the feature works in 3ds Max 2020.0 and any 2019 builds. We have reported the regression to Autodesk.

Here is what is happening:

In 3ds Max 2019, Autodesk added a keyword argument and property called autoLayoutOnResize which, when set to True, allows the Command Panel to auto-resize and move the UI controls to make use of the additional real estate when the panel is resized horizontally. It also lets the developer query the actual new width of the resized panel.

We set this property to True for all rollouts in scripted plugins which include the Krakatoa PRT Loader, and all Stoke objects. We have some additional code to resize controls, but we depend on this property to get this extra code functioning properly in 2019 and higher.

The regression causes any scripted rollout that has this option set to True to basically make all controls disappear. This happens with ANY scripted plugin, not just Thinkbox products. I provided Autodesk with an example where simply adding the keyword argument to a scripted plugin taken from the MAXScript Documentation reproduces the issue.


Temporary Fix

Attached is a modified PRT Loader script file which should turn off the option in 3ds Max 2020.1, but keep it on in previous versions.

To deploy the fix, you should

  • Navigate to your Krakatoa installation and locate the Scripts folder, usually under C:\Program Files\Thinkbox\Krakatoa MX\Scripts
  • Right-click the file KrakatoaPRTLoader.ms and change its Security settings to allow your current user to Write the file (it is Read-only by default)
  • Rename the file to .bak
  • Copy the patched file into the same folder to take its place.
  • Restart 3ds Max 2020.1 and create a PRT Loader

KrakatoaPRTLoader_2.9_20190619.zip (18.6 KB)