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Assign Vertex Color

Writes a flat color into a mesh's color attribute, either on the selected vertices in Edit Mode or on every vertex/corner of selected mesh objects in Object Mode. The color source is the Scene.IOPS.iops_vertex_color picker, with quick override toggles for solid black, grey, and white. Missing color attributes are created on the fly using the chosen domain and data type.

Assign Vertex Color

bl_idname: iops.mesh_assign_vertex_color Mode: Object / Edit Mesh Context: VIEW_3D Modal: no HUD: no

Overview

A single-shot color writer for the active color attribute. It bridges the gap between Blender's vertex paint workflow and a simple "fill selected with this color" action that survives mode switches. In Edit Mesh it only touches selected geometry; in Object Mode it fills every element of the attribute on each selected mesh.

If the target object has no color attribute, a new one is created using Color Attribute Name, Attribute Type, and Domain from the operator props. Newly created attributes are made active.

Usage

  • Requires an active mesh object. In Edit Mesh, vertices must be selected to receive color; in Object Mode, every element of the attribute is filled.
  • No default keymap binding — invoke via menu/search or a custom shortcut.
  • Pick a color in the F6 redo panel (or via the Scene IOPS color slot) and run the operator. Use one of the Fill Black / Grey / White toggles for a quick override; those flags reset to off after each run.

Properties

Name Type Default Description
use_active_color Bool True Write to the mesh's active color attribute. If unset, uses col_attr_name.
col_attr_name String Color Name of the color attribute to create or target when not using the active one.
fill_color_black Bool False One-shot override: fill with (0, 0, 0, 1). Auto-resets after execution.
fill_color_white Bool False One-shot override: fill with (1, 1, 1, 1). Auto-resets after execution.
fill_color_grey Bool False One-shot override: fill with (0.5, 0.5, 0.5, 1). Auto-resets after execution.
domain Enum POINT Domain for newly created attributes. Items: POINT (Point), CORNER (Corner).
attr_type Enum FLOAT_COLOR Data type for newly created attributes. Items: FLOAT_COLOR (Float Color), BYTE_COLOR (Byte Color).
use_override_color Bool False Fill with override_color instead of the picker / black-grey-white flags. Not auto-reset (driven by callers like the Vertex Color widget).
override_color Float[4] (1, 0, 0, 1) Explicit RGBA fill color used when use_override_color is on. Wins over the scene picker and the fill flags.

The base color comes from context.scene.IOPS.iops_vertex_color. The fill toggles take precedence in order black > grey > white.

Notes

  • Edit Mesh path: iterates selected vertices for POINT-domain attributes; for CORNER-domain it fills every loop of any face that has at least one selected vert.
  • Object Mode path: fills the entire attribute data array, regardless of vertex selection state.
  • All selected mesh objects are processed, not just the active one. If an object lacks the target attribute, one is created and set active.
  • The fill flags (fill_color_black/grey/white) are mutated to False inside execute() after a run, so reopening the redo panel will not stick on a previous override.
  • A WARNING is reported if the active object is not a mesh and the mode is neither Edit nor Object.

Assign Vertex Color Alpha (bl_idname: iops.mesh_assign_vertex_color_alpha)

bl_idname: iops.mesh_assign_vertex_color_alpha Mode: Edit Mesh Context: VIEW_3D Modal: no HUD: no

Overview

Writes only the alpha channel of the active color attribute on selected vertices, leaving RGB untouched. Useful when alpha is used as a mask, weight, or AO channel and you don't want to disturb existing color data.

Usage

  • Requires an active mesh object in Edit Mode.
  • No default keymap binding.
  • The operator temporarily switches to Object Mode to read selection state, applies the alpha, then returns to Edit Mode.

Properties

Name Type Default Description
vertex_color_alpha Float 1.0 Alpha value to write. Range 0.0 (transparent) – 1.0 (solid).

Notes

  • If the mesh has no color attribute, a new one named Color of type FLOAT_COLOR on the CORNER domain is created before writing.
  • If there is no active color attribute but at least one exists, the first attribute becomes active and is used.
  • POINT domain: alpha is written per selected vertex. CORNER domain: alpha is written for every loop whose vertex is selected.
  • Wrapped in a try/except — on failure the operator attempts to restore Edit Mode and reports an ERROR.

Vertex Color Preview (viewport)

A reversible viewport preview of the active color attribute, driven by the Vertex Color widget's Preview VC toggle (scene.IOPS.iops_vc_preview).

  • Turning it on builds/reuses a temporary material IOPS_VC_Preview (Color Attribute → Emission → Material Output) and assigns it to view_layer.material_override. Emission is unlit, so the raw vertex color reads correctly in both EEVEE and Cycles. The shading switch is context-aware: if the active 3D viewport is already in Rendered (EEVEE or Cycles) or Material Preview, it is left unchanged, respecting whatever engine/mode is already active. Only a Solid (or Wireframe) viewport is switched to Material Preview (EEVEE-based, which shows the override regardless of the scene's render engine).
  • Turning it off clears the override and restores the previous viewport shading if one was stored (stored in scene.IOPS.iops_vc_preview_prev_shading, only when the viewport was switched on enable).
  • Implemented by vc_preview_set(context, enable) in operators/assign_vertex_color.py; the toggle is view-layer-wide (every object renders as its vertex color while active) and mutates no user materials.

The widget's Black and White fill swatches use the same explicit-color override as R/G/B (use_override_color with override_color (0,0,0,1) / (1,1,1,1)).

Vertex Color Channel (bl_idname: iops.mesh_vertex_color_channel)

Sets, adds to, or subtracts from a single R/G/B channel of the active color attribute on the selection, preserving the other channels and alpha.

Properties

Name Type Default Description
channel Enum R Target channel: R / G / B.
mode Enum SET SET (=): set channel to 1.0 and zero the other two RGB channels; ADD (+): min(1, channel + amount); SUB (−): max(0, channel − amount).
amount Float 1.0 Step for ADD / SUB.

Alpha is always preserved. Works in Edit Mesh (selected verts / corners of faces with a selected vert) and Object Mode (whole attribute), on POINT/CORNER domains and FLOAT_COLOR/BYTE_COLOR types. If the active object has no color attribute, a default Color (FLOAT_COLOR, POINT) is created.

The Vertex Color widget's "Fill RGB" section drives this operator: each channel is a row of a colored swatch (=, pure fill via mode=SET) plus + (ADD) and − (SUB) buttons.