DriverHelper

DriverHelper is a Blender add-on that helps you quickly generate normalized driver expressions for Shape Keys and other float properties.

Features

• Instantly create driver formulas for Location, Rotation, or Scale.
• Normalize any value range to [0, 1] for easy use in Shape Keys and other drivers.
• Supports custom easing (linear, ease-in, ease-out, etc.) with a Power parameter.

How It Works

1. Add a driver to your Shape Key or any float property as usual.
2. In the Shape Keys panel, use the DriverHelper UI:
   • Driver Mode: Choose what you want to drive by (Location, Rotation, or Scale).
   • Min / Max: Set the minimum and maximum values of your input range. These will be mapped to 0 and 1, respectively.
   • Power: Adjust the curve of the transition:
     • 1.0 = Linear
     • 2.0 = Ease-in (quadratic)
     • 3.0 = Ease-in (cubic)
     • 0.5 = Ease-out
3. Click Generate Formula. A popup will appear with the generated driver expression.
4. Copy the formula and paste it into your driver expression field in Blender.

Example

Suppose you want a Shape Key to activate fully when a bone rotates from 0° to 90° (in Blender, driver variables for rotation are in radians):

• Driver Mode: ROT
• Min: 0
• Max: 90
• Power: 2.0 Ease-in (quadratic)

Click Generate Formula. The popup will show:

pow(min(max(var/1.5707963267948966,0),1),2.0)

Paste this into your driver expression. Now, when the bone's rotation is 0°, the value is 0; at 90°, it's 1.

Notes

• For ROT mode, enter angles in degrees; the add-on will convert them to radians for you.
• The variable var in the formula refers to your driver variable (e.g., a bone's rotation).
• You can use this for any float property that supports drivers, not just Shape Keys.