Blender has several features for using brushes. From sculpt mode to texture painting and weight painting. No matter what you are currently trying to paint, it is important to have good control over your brush settings. Changing the size is one of the fundamental settings that we often must adjust.
To change the size of your brush, press the F key and move your mouse, you will see a visual indicator of the size change. To lock in the new size, press left mouse button.
While we are at it, using Shift+F will let you change the strength instead.
Let's now dive into the details of changing the brush size. Some common pitfalls when painting that are related to brush size and some variations between size settings in different modes.
To change the brush size in sculpt mode we have a few different options. The first one is using the F key as described above followed by dragging the mouse and left click to confirm the new size. But we can also change the brush size using the radius slider in the header as well as the right-side properties panel.
To change the brush size using the header, find the radius widget just to the left of the strength slider. Either click it and type the size you want or click hold and drag the slider.
We can find the same slider in the right-side properties panel. Bring it up by pressing N then go to the tools tab and expand the brush setting section. The topmost slider is the radius slider, and it works the same way as the slider in the header.
Sculpt mode also has this feature where we can base the brush size on either the view or the scene. You can find this setting just below the radius setting in the properties panel or by pressing the brush menu in the header. There you will find the brush radius unit as the first setting.
The difference between view and scene is that when set to view, the brush size will be in pixels and based on the view. So, if you zoom in the view, the brush will sculpt smaller on your mesh.
If instead we set the radius unit to scene, the size of the brush is fixed and does not change as we zoom the view. Instead of pixels the radius unit change the scene units. This is a feature that we don't have when for example texture painting but hopefully it is an upcomming feature.
You may have noticed that there is a button to the right of your radius setting and similarly there is an identical icon to the right of the strength slider.
If you have a pen tabled or display that supports pressure sensitivity, you can press this button so that it turns blue to enable this feature for either the size, strength, or both. In that case we set the maximum radius or strength we can reach through pressure, so you might want to turn up the values slightly so that you don't have to press as hard.
When texture painting, we can either paint directly in the 3D viewport or the image editor. The brush size in both of these editors is linked meaning that if we change the size in one, we will change the size in the other as well.
Let's start with the 3D viewport. While in texture paint mode, we find the radius slider in the header a little further to the right compared to sculpt mode, but still next to the strength setting. Here we also have the pressure sensitivity next to each slider so that we can use pen tabled pressure if we have one.
Likewise, we can press N and navigate to the tool tab and expand the brush settings to find the radius slider as the second option just below the blend mode.
Similarly, we can find the radius slider in the image editor both in the header or using the right-hand side properties panel.
Of course, the F key works as well to change the brush size together with Shift+F for the strength
As I was testing this, I found a few issues that you might run into, so let's cover them here.
While in the 3D viewport, no matter your brush size, if you zoom in too far, I noticed that my brush strokes did not make a mark. Simply zoom out further and try to paint again. Another reason that you might not be able to paint is that your blend mode might be set to something that simply doesn't give a change in color.
To change the blend mode, go to the right-side panel by pressing N then go to the tools tab and expand the brush settings section if it is not already open and change the blend mode. The default is called mix and that should work for you to at least give of a mark as you paint.
Similarly, to sculpting and texture painting, we can change the brush size with F, in the properties panel, by opening the N panel or in the header.
In weight painting we are not painting a color though, instead we are painting a value between 0 and 1 for each vertex in our mesh. This is represented by blue for zero and red for one and a scale from green to yellow and orange for the values inbetween.
Related content: How to weight paint in Blender
In vertex paint mode it is like a mix between texture painting and texture painting. Instead of painting on a texture that we mapped to our object, we assign color values directly to each vertex and the density of the mesh determines how dense or how high the resolution of that color will be.
In this article we learned that there are many ways we can change the brush size in Blender for some of the ways we can paint or use brushes in Blender.
What we didn't cover was grease pencil. For that, you can start here:
Related content: Can you draw with Blender?
Thanks for your time.
