Relax Brush

The Relax Brush tool allows you to easily and interactively smooth out vertex positions while keeping them on the surface of the source mesh.

You can quickly use the Relax tool while in any other Retopoflow tool with Shift LMB Drag.

Transforming

To use the Relax Brush, simply LMB Drag on vertices. Which vertices are affected can be controlled in the Masking settings.

Brush Settings

• Radius controls the size of the brush and can be adjusted with the hotkey F
• Strength controls how much the brush effects the geometry and can be adjusted with the hotkey Shift F
• Falloff controls how much the strength of the brush is feathered near the edges and can be adjusted with the hotkey Ctrl F

Pinning

You can pin vertices in both Tweak and Relax by selecting them and using the Pin Selected operator in the tool settings. Unpin them by selecting them again and using Unpin Selected.

Pins only affect the brush tools and you can still transform pinned vertices using Grab, Rotate, or Scale.

Retopoflow’s pinning uses Blender’s vertex crease system under the hood to maximize performance and avoid having to keep a copy of the mesh in memory for custom drawing. Because of this, pins are only visible in vertex select mode, so be sure you are in that mode to check for pins if something appears stuck. Retopoflow will preserve vertex creases and allows you to use them separately for masking, but you may see strange behavior if you active adjust creases while inside of Retopoflow tools. If you need to adjust creases while Retopoflow tools are active, you can turn off the pinning system in the Tool Switching preferences and use another attribute (like seams or sharp edges) for pinning instead.

Masking Settings

The Relax Brush has several options to control which vertices are moved and how.

Boundary

• Exclude does not affect vertices along the mesh boundary.
• Slide moves vertices along boundary but only by sliding them along the boundary loop.
• Include moves all vertices under the brush including those along the boundary.

Selected

• Exclude moves only unselected vertices.
• Only moves only selected vertices.
• All moves all vertices within brush regardless of selection.

Transform

• Corners allows moving boundary vertices that are inner or outer corners
• Seams allows moving vertices that are on an edge with a seam
• Sharps allows moving vertices that are on an edge that is marked sharp
• Creases allows moving vertices that have a vertex crease or are on an edge that is creased
• Pinned allows moving vertices that are marked as pins by Retopoflow
• Occluded allows moving all vertices within the brush regardless of whether it is behind another mesh or not.

Algorithm Settings

The Relax Brush is not just averaging vertex locations like a simple smooth brush! Instead, it is more like a simulation that moves vertices towards an optimal arrangement.

Method controls how the below influences are applied while drawing with the brush. The default, Steps, averages multiple iterations while RK4 uses a Runge-Kutta approach to improve stability.

Iterations determines how many times the relax algorithm is run per update. A higher value leads to more agressive smoothing. It is recommended to try increasing the brush strength before increasing this setting.

Strength multiplies how much each iteration affects the result.

Average Edge Lengths enables adjusting the length of edges to move towards the average edge length under the brush.

Average Face Radius enables adjusting the length of edges so that each face’s radius moves towards the average of all face radii under the brush.

Average Face Angles enables moving vertices so that the angle of each corner of each face moves towards the same value.

Average Face Lengths enables adjusting the length of edges to move towards the average length of all edges that share the same face. This option is still experimental and can cause faces to flip.

Straighten Edges enables moving vertices so that their edge loops straighten out.

Correct Flipped Faces attempts to make sure the direction of the face normals under the brush are consistent.

Selection

Even though LMB to select is not available while using the Tweak Brush, you can still select and deselect by using Shift LMB. Box Select B and Lasso Select Ctrl Right Mouse Drag are always available as well.

General selection options for all tools can be read about on the Retopoflow Mode docs page under Selection.