Options For Smoothly Scaling Bezier Curve Bevels In Blender

Adjusting Bevel Settings for Smoothness

One of the most impactful ways to improve the smoothness of a beveled edge in Blender is to adjust the bevel settings themselves. By changing the bevel profile from a custom shape to a half or full round shape, more supportive geometry is automatically generated, removing angular banding artifacts. Additionally, increasing the number of bevel resolution segments provides more geometry along the beveled area to smooth out the shape. Enabling the “Loop Slide” option in the bevel settings allows this new geometry to be evenly distributed along the adjacent edges, enhancing smoothness.

Changing Bevel Profile from Custom to Half or Full

The bevel tool in Blender provides several built-in profile shapes that can be used when beveling edges. By default, a custom profile is used which matches the exact shape of the selected edge. This often results in angular bandingartifacts along curves. Switching the profile to half or full round options adds more geometry and smoothing without the need for additional segments.

1. In edit mode, select the edges you wish to bevel
2. In the toolbar, locate the bevel settings
3. Change the profile from custom to half or full
4. Observe smoothing introduced along the bevel

Increasing Bevel Resolution Segments

The segments setting in the bevel tool controls how many concentric rings of geometry are created along the beveled face. Higher values smooth the shape. However, too many segments can also negatively impact performance.

1. With edges selected, adjust bevel segments in toolbar
2. Increase segments until smooth bevel achieved
3. Utilize segment modifier to selectively increase segments only on curved areas

Enabling ‘Loop Slide’ for Even Distribution

The loop slide option in the bevel tool tells Blender to evenly distribute the supportive geometry added during the bevel operation. This helps minimize uneven banding by spreading additional edge loops smoothly along the mesh.

1. In bevel settings, check the Loop Slide box
2. New geometry flows cleanly along edges

Using Supporting Geometry

Adding additional edge loops adjacent to beveled edges can greatly enhance smoothness. The edge loops provide geometry for the bevel tool to blend smoothly into. This topology flow is critical for creating a clean beveled surface.

Adding Edge Loops Near Beveled Edges

Manually placing edge loops allows precise control over topology flow. More loops near curved areas, fewer on straight edges. Follow bevel contour for best results.

bpy.ops.mesh.loopcut(number_cuts=3)

This script demonstrates how to automatically add 3 edge loops along a selection with Python. The loops will follow the contours of the mesh surface.

Improving Topology Flow

In addition to adding more supporting edge loops, improving overall topology flow will enhance bevel smoothness. Relaxing geometry distortions through limited dissolve operations can help align topology along natural contours.

Relaxing Geometry with Limited Dissolve

The limited dissolve operation slightly smooths geometry by removing underutilized edges and faces. This relaxation can improve bevel topology flow.

bpy.ops.mesh.dissolve_limited() 

Dissolve limited automatically removes distracting geometry. Use iteration count to control strength of operation.

Optimizing Geometry

Once supporting geometry in place, optimization tools like decimation can reduce polygons while still preserving desired bevel smoothness.

Decimating Mesh While Preserving Bevel Shape

The decimate modifier reduces overall polygon count, targeting underutilized geometry while attempting to preserve essential shape characteristics.

bpy.ops.mesh.decimate()

Proper use of decimate modifier optimizes topology without damaging bevel shape. Iterate settings for best results. Other modifiers like filters can also improve mesh density.

Troubleshooting Banding and Pinching

Despite best efforts, sometimes beveled edges still exhibit angular banding, distortion, pinching and other artifacts. Identifying the problem areas to apply targeted adjustments can help troubleshoot these issues.

Identifying Problem Areas on Mesh

Angular distortions most commonly occur along areas of high curvature. Use gizmos to analyze geometry shape. Mark distortions clearly before adjusting.

Using Bevel Weight to Selectively Adjust

Painting bevel weight onto edges allows custom control over the bevel intensity across the mesh. Increase bevel weight to smooth distortions.

1. Enable Bevel Weight overlay mode
2. Paint higher weight values on problem edges
3. Only those edges receive more intense beveling

Achieving Smooth Curves with Subdivision Surface

Adding a subdivision surface (subsurf) modifier after beveling is complete provides iterative smoothing without destroying bevel shape. Useful for final polish.

Adding Subdivision Surface Modifier

Subsurf adds smoothing by dividing mesh faces and displacing vertices. Does not change vertex count allowing optimization first.

1. With mesh optimized, add subsurf modifier
2. Increase viewport and render iterations to smooth bevels

Increasing View and Render Iterations

The viewport and render iteration settings control subsurf performance impact and strength of the smoothing effect. Can refine mesh infinitely but increases geometry.

Summary

Smoothly scaling bezier curve bevels requires adjusting bevel settings, adding supporting loops, optimizing topology flow, troubleshooting distortions, and finally polishing with subdivision. Follow these key guidelines to create flawlessly smooth beveled surfaces within Blender.