Q100314: Wacom Pressure Sensitivity updates on Linux may cause issues with Mari and Nuke

Follow

SUMMARY 

Some Linux versions, such as CentOS 6.9, are now shipping with a X11 Wacom driver (0.34.2) that has modified the existing pressure sensitivity range from 0 - 2048 to an extended 0 - 65535 range. This is causing issues with pressure sensitivity recognition in some products such as Nuke and Mari where sensitivity values above 2047 are ignored, causing unexpected behaviour for users.

 

CAUSE

The latest Wacom driver has changed the sensitivity range from 0 - 2048 to 0 - 65535, which neither Mari or Nuke yet support. What this means is that, any pressure over 2048 (which on a range of 0 - 65535 would only cover 3% of all values) will not be registered by Mari, and so it will not draw. 

           
      Fig 1: An example of using the 0 - 2048 pressure      Fig 2: An example of using the 0 - 65535 pressure 
        sensitivity range in Mari.                                              sensitivity range in Mari.

 

In Nuke, this modification to the Pressure Sensitivity range can be examined when attempting to use the RotoPaint node. In the example below, only the lightest pressure is registered correctly when using the Clone Stamp brush; any pressure above the 2048 range creates unexpected results and incorrect, saturated colours when cloning and painting. 

 


Fig 3: An example of using the 0 - 2048 pressure sensitivity range in Nuke


Fig 4: An example of using the 0 - 65535 pressure sensitivity range in Nuke

 

RESOLUTION

Since performing our own tests in house, we have logged separate feature requests for each product to implement additional support for the new 0.34.0 Wacom driver in a future release. For reference, these are logged internally as:

TP 280527 - Add support in Mari for extended pressure sensitivity levels introduced in new Wacom drivers

TP 280528 - Add support in Nuke for extended pressure sensitivity levels introduced in new Wacom drivers


Until we are able to offer support for this extended 0 - 66535 range, there are two possible solutions depending on the capability of your machine and whether or not the driver came pre-installed. You should try:
 
1) If you are able, you will need to roll back to a Wacom driver predating 0.34.2

2) If you are unable to roll back your drivers, you will need to make use of the latest patch of the 'master' branch in Wacom's GIT repository. This patch exposes a "Pressure2K" option that can be used to force the driver into reverting back to 2048 pressure levels.
 
After installing the updated driver, please create a file in the /etc/X11/xorg.conf.d directory with the following contents:
 
Section "InputClass"
Identifier "Wacom pressure compatibility"
MatchDriver "wacom"
Option "Pressure2K" "true"
EndSection
 
Note: This option is only available through xorg.conf / xorg.conf.d. 
 
In some cases you may find that your modifier keys, such as [CTRL] and [ALT] misbehave after implementing the above workflow. If this happens, please check that your Movement Key is set to 'Super (or 'Windows Logo') so that this does not interfere with any product shortcuts and then restart Mari and/or Nuke. 
 
You can find this dialog located in your Linux System preferences under (System > Preferences > Windows).


Fig 3: System > Preferences > Windows > Movement Key
 
Was this article helpful?
0 out of 0 found this helpful