Brush

Left-click and drag to paint visible faces. The BFS brush spreads along the surface within the radius, staying on the same surface (won't bleed around corners). Adjust radius with the slider.

Sphere Brush

Paints all faces within a 3D sphere radius, including through the model. Useful for painting hollow or complex geometry. Adjust radius with the slider.

Fill

Connected mode: flood-fills all connected faces of the same colour. Angle Limit mode: fills faces within an angle threshold — great for painting a single flat surface.

Colour Picker (Eyedropper)

Click any face to sample its colour into the active paint colour.

Base Colour

Sets the colour for all unpainted faces. "Reset all to base" clears all painting.

Whole Model mode

1. Select gradient colours (From / To) using the colour swatches.
2. Set Direction using the Rotation and Pitch sliders. The purple arrow in the viewport shows the direction.
3. Use the Centre slider to shift where the mid-point of the gradient sits.
4. Adjust Steps to control how many discrete colour bands the gradient uses.
5. Click Apply Gradient.

Selection mode

1. Switch to Selection mode in the gradient panel.
2. Use the Brush or Fill sub-tool to select the faces you want to gradient.
3. Click on the model to set your Start point, then click again for the End point.
4. Click Apply Gradient.

The gradient tool automatically switches back to the Brush tool after applying.

How to use

1. Select the Photo tool from the tool panel.
2. Click Load Photo and choose a JPG or PNG. Transparent PNG backgrounds are respected.
3. Position, resize, and rotate the photo overlay in the viewport so it covers the area you want to paint.
4. Choose Whole Model (paints all visible faces) or Selection mode (only selected faces).
5. In Selection mode, use the Brush or Fill sub-tool to select the hull faces you want to paint first.
6. Click Apply. Filament mode auto-switches to WKCMY for best results with photos.

⚠️ Limitations

Curved surfaces work best. The photo tool maps colours onto individual triangles using a camera projection. On a model with many small triangles (like a curved hull), the result looks excellent. On a perfectly flat surface with very few triangles — like a basic cube face with only 2 triangles — the resolution is limited to a few samples per face.

Apply photo before scaling. If you scale the model after applying the photo, the per-layer export colours will fall back to the face average colour (still correct, but without the fine per-layer variation).

Use WKCMY. Photos contain neutral greys, whites, and blacks that CMY alone can't reproduce well. WKCMY uses white and black filaments to handle these tones accurately.

Bright, high-contrast photos print best. The dithering works on colour differences — a washed-out or grey photo will print as grey.

Dithered export (CMY / WCMY / KCMY / WKCMY / 2-Filament)

The model is sliced into 0.08mm layers and each layer slice is assigned a filament (Cyan, Magenta, Yellow, White, Black). The alternating filament lines optically mix to produce your painted colours. Requires specific slicer settings — 0.08mm layer height, filaments assigned in the correct order.

CMY — 3 filaments, best for vibrant colours with a white printer base.
WCMY — 4 filaments, adds white for cleaner pastels and highlights.
KCMY — 4 filaments, adds black for richer darks.
WKCMY — 5 filaments, best overall accuracy.
2 Filaments — dual nozzle, dithers between two chosen colours.

Solid Colours — No Dithering ✦

Exports each painted face as a solid flat colour. This is NOT the dithered colour-blending export — it's for use with normal multi-colour FDM printing. Use this if you want to paint your model and print it on a multi-filament printer (like a Bambu AMS) using standard solid filament colours, without any CMY dithering. No special slicer settings required.

The Palette Size option reduces all painted colours to a fixed number using colour clustering (k-means). Set this to match the number of filament slots in your slicer — e.g. choose 8 colours for an 8-slot AMS. Colours are automatically merged toward their nearest neighbours so the most visually distinct colours are preserved.

Re-importing into Primed3D: The Solid Colours export also works as a project save format. Export as Solid (Full Spectrum), then re-import the resulting .3mf into Primed3D to continue editing — all your painted colours are preserved on the faces and can be further refined with the brush, gradient, or photo tools before re-exporting as a dithered CMY version.

Filament Colours

Use the 🎨 Filament Colours button to set the actual hex codes of your filaments. This only affects how the slicer preview displays — the dithering ratios themselves are always computed using ideal CMY theory regardless of your specific filament brand.