Measuring diagonal wobble

I measure diagonal wobble using a simple procedure

Resources

Diagonal template image - a standard PNG file created with using Adobe Illustrator. This provides visual guides that make it easier for the testing. Image is shown later in this doc.

Ruler - I use a simple plastic ruler. I do not use metal rulers because they might interfere with the EMR tech in the pen.

Driver - I use the latest manufacturer driver. For very old tablets that don't have recent drivers, I use OpenTabletDriver.

Application - Krita

Testing process

• Verify the plastic ruler has no rough spots or bumps that would affect the measurement. It should be smooth.

• Tablet configuration

  • For pen tablets, set the active area to a single display.

  • For pen tablets, set the driver to match the aspect ratio of the tablet to the display.

• App configruation

  • Load the diagonal template image

  • Set Krita zoom to 100%.

  • Set Brush to Ink-2 Fineliner with default brush settings and set size to 5 pixels.

  • 
• Drawing

  • The template requires 3 sets of lines drawn at different speeds - 3 lines for each speed

  • Draw the line from the lower left to the upper right.

    • Follow the specified speed as much as possible

    • pen tilt = about 30 to 40 degrees from vertical.

• Save as a PNG

Evaluation wobble (DRAFT)

Considerations

• MAGNITUDE - how wobble is physical displaced from "center" of line.

• VELOCITY - Is wobble visible in slow, medium, fast strokes

Scale

• VERY LOW - Strokes easily confused for a perfectly straight line

• LOW - lines mostly straight with occasional and minor wobble

• MEDIUM - moderate Wobble visible in majority of lines

• HIGH - moderate wobble available in lots of lines

• VERR HIGH - lots of wobbling in lines

Wobble testing template image