How to Change Proportional Size in Blender?

In Blender, you change the proportional size, also known as the influence radius of Proportional Editing, primarily by using your mouse wheel during a transformation or by adjusting a slider in the Redo panel immediately after an operation.

Understanding Proportional Editing

Proportional Editing is a powerful feature in Blender that allows you to transform (move, scale, or rotate) selected elements (vertices, edges, faces, or objects) while simultaneously affecting nearby unselected elements. The "proportional size" refers to the radius or sphere of influence around your selection, determining how far out the transformation affects other parts of your model. It's incredibly useful for making smooth, organic changes to your mesh, avoiding sharp, unnatural deformations.

Activating Proportional Editing

Before you can change its size, Proportional Editing must be enabled. You can do this in a couple of ways:

Keyboard Shortcut: Press the O key on your keyboard. This acts as a toggle to turn it on or off.
UI Button: Click the "Proportional Editing" icon (looks like two concentric circles) located in the header of the 3D Viewport, usually next to the Snap toggle.

Once activated, when you begin a transformation, a white circle will appear in the 3D View, indicating the current proportional size.

Adjusting Proportional Size During Transformation

The most common and intuitive way to change the proportional size is while you are performing a transformation (e.g., moving, scaling, or rotating).

Mouse Wheel: After initiating a transform operation (e.g., G for Grab/Move, S for Scale, R for Rotate), scroll your mouse wheel (scroll up or down). Scrolling up will increase the radius, while scrolling down will decrease it.
Page Up/Page Down Keys: Alternatively, you can use the Page Up and Page Down keys to adjust the radius during a transform.

As you adjust, the white circle in the 3D View will visually expand or contract, showing you the active area of influence.

Fine-Tuning with the Redo Panel (After Operation)

For precise control or to make adjustments immediately after completing a transform operation, Blender provides the Redo panel.

As per the reference, "In the Redo panel located at the bottom of the Tool Shelf ( N in the 3D view) or found by pressing F6, there is a slider to adjust the Proportional size. Note that this only applies immediately after a transform operation."

Here's how to use it:

Perform your transformation with Proportional Editing enabled (e.g., move a vertex).
Immediately after completing the operation (before performing any other action), access the Redo panel:
- Press F6 on your keyboard.
- Alternatively, open the Tool Shelf (also known as the N panel) by pressing N in the 3D Viewport, and look for the Adjust Last Operation (or Redo) panel at the very bottom.
Within this panel, you will find a Proportional Size slider. You can drag this slider to precisely adjust the radius of influence of your last operation.

This method is particularly useful if you need to numerically input a specific radius or fine-tune the effect after observing the initial result.

Proportional Falloff Types

While not directly changing the "size," understanding falloff types is crucial as they define how the proportional influence is distributed within the defined size. The falloff type determines the curve of the transformation's intensity from the center to the edge of the influence radius. You can select a falloff type from the dropdown menu next to the Proportional Editing toggle button in the 3D Viewport header.

Common falloff types include:

Smooth: A gentle, gradual falloff.
Sphere: A more pronounced, spherical influence.
Root: A sharper falloff near the center, then gradual.
Inverse Square: Intensity drops off rapidly from the center.
Constant: Applies the full transformation within the radius, then nothing outside.
Random: Applies random transformation within the radius.

Experimenting with these types allows for diverse and complex organic modifications.

Step-by-Step Guide to Proportional Resizing

Here’s a quick workflow for using proportional editing and adjusting its size:

Select the object or components (vertices, edges, faces) you wish to transform.
Enable Proportional Editing by pressing O or clicking the icon in the 3D View header.
Choose a Falloff Type from the dropdown menu next to the toggle button (optional, defaults to Smooth).
Initiate a Transformation (e.g., G to move, S to scale, R to rotate).
Adjust the Proportional Size by scrolling your mouse wheel up or down. Observe the white circle to see the influence radius.
Confirm the Transformation by left-clicking.
(Optional) Fine-tune by pressing F6 immediately or opening the N panel to adjust the Proportional Size slider in the Redo panel.

Key Shortcuts for Proportional Editing

Mastering these shortcuts will significantly speed up your workflow:

Action	Shortcut	Description
Toggle Proportional Editing	`O`	Turns proportional editing on or off.
Adjust Proportional Size	`Mouse Wheel`	Changes the radius during a transform operation.
Adjust Proportional Size	`Page Up`/`Page Down`	Alternative to mouse wheel during a transform.
Open Redo Panel	`F6`	Accesses the `Adjust Last Operation` panel for post-transform fine-tuning.
Open Tool Shelf / N Panel	`N`	Contains the `Adjust Last Operation` (Redo) panel at the bottom.

By understanding these methods, you can effectively control the proportional size in Blender, enabling you to create intricate and smooth deformations with ease.

askvity