Import Meshed Alpha

Import Meshed Alpha provides an operator to automatically create mesh objects based on an image's alpha channel.

Images can be provided to the tool through either the addon's import menu or by converting existing image reference planes whose object transforms they will inherit. Meshing can be refined though several pre-processing operations which can be tweaked non-destructively. Generated meshed are fully uv unwrapped and optionally assigned a new material with convenience shortcuts to set image sampling parameters.

Usage

1. Using the new add menu item Add Menu > Image > Meshed Alpha, select the image you'd like to generate a mesh from and click Import Meshed Alpha. Alternatively, right click on a image reference object and select Convert to Meshed Alpha
2. Controls for the conversion can be found in the object properties panel under Alpha to Mesh.
3. Optionally, once satisfied with the conversion settings the Finalize button can be used to prevent further editing.

Parameters

Image Processing

• RGB as Alpha: Generate alpha channel from RGB channels. Enabled automatically is necessary
• Method: Method to use for RGB as Alpha Conversion
  1. Luma: Luminance. Weighted (0.2126, 0.7152, 0.0722)
  2. Min: Darkest value per channel
  3. Max: Brightest value per channel
• Black/White Points: Set the back and white points of the image.
• Invert Alpha: Invert the alpha channel.
• Predivide: Divide the alpha channel by itself.
• Dilate/Erode: Dilate with positive values or erode with negative.
• Output Preprocessing Image: Output the result of the image pre-processing step to an image datablock. This is the image used by the image to mesh converted.

Tracing

• Curve Fitting: How the alpha channel is traced internally. Spline traces with curves, Poly with polylines, and None traces per pixel.
• X/Y Align: Align the mesh to the extents of target axis.
• Finalize: Disable further editing of this objects conversion parameters. If the user is concerned about undoing any manual editing to the new mesh object by accidentally changing a property in the addon panel, finalizing the object will remove that possibility.

Mesh Post Processing

• Dissolve Surface: By default meshed are triangulated. This toggle will dissolve inline edges to create ngons where possible.
• XY Divisions: Slice the mesh evenly by the given values.
• Divide Ngons: Triangulate ngons.
• Remove Small Islands: Remove mesh islands whose area, relative to the input image, is smaller than the provided value.

Material Settings

The Default Material is currently intended for quick visualization only

• Use Default: Apply the default material.
• Texture Override Use a different surface texture.
• Default Material Type: Surface rendering type for the default material.
• Default Material Interpolation: Convenience shortcut interpolation parameter of the default material's texture node.
• Default Material Alpha: Convenience shortcut alpha parameter of the default material's texture node.
• Apply Remapped Alpha: Apply the remapped black and white points to the default material's alpha component.
• EEVEE: Render Method: Shortcut to the Eevee specific material setting that determines alpha rendering treatment.
• Alpha: Shortcut to material's texture node alpha property
• Color space: Shortcut to material's texture node color space property

Common Issues/Limitations

1. Material Colors Wrong: Adjust Alpha to Mesh > Material > Color Space to better match scene color management settings. Eg. AgX Base sRGB for AgX
2. Meshing Errors. Without creating a face per pixel, some mesh errors are inevitable: In most cases the meshing can be corrected by experimenting with dilation, pre-dividing, and curve fitting.
3. Need minor mesh adjustment, eg: edges are too tight: First, try the predivide toggle. For minor manual adjustments, in edit mode the mesh can be adjusted without stretching the UVs by first enabling Correct Face Attributes (N Sidebar > Tool > Options > Transform > Correct Face Attributes). Note that any manual mesh adjustments will be undone if the tracing parameters are adjusted afterward. That includes any parameter in the Alpha to Mesh panel except Finalize and material controls.
4. Small islands: Usually the product of a messy alpha channel and can be corrected with Mesh Post > Remove Small Islands
5. Pixel Art is Blurry: Set material interpolation to Closest

Included Wheels

vtracer | MIT | https://github.com/visioncortex/vtracer