Paint-on features in the online slicer

The paint-on tools in SimplyPrint's online slicer let you take fine-grained control over your prints. Instead of relying on automatic detection, you can paint directly on your model to specify exactly where colors go, where supports should be, where seams should be hidden, and which areas get fuzzy skin texture.

In this article

• What you can paint
• How to enter paint mode
• The paint panel
• Painting and erasing
• Color painting
• Support painting
• Seam painting
• Fuzzy skin painting
• Clearing paint
• Exiting paint mode
• Keyboard shortcuts
• Tips for better results

What you can paint

The slicer includes four paint-on modes:

• Color painting - Assign different extruders/filaments to specific areas for multi-color prints
• Support painting - Mark areas that need supports (enforcer) or should never have supports (blocker)
• Seam painting - Control where layer seams appear or are hidden on your model
• Fuzzy skin painting - Apply a textured surface finish to selected regions

How to enter paint mode

1. Upload or open a model in the slicer.
2. Select the object you want to paint.
3. Click one of the paint icons in the top toolbar - color, support, seam, or fuzzy skin.

The scene will switch to an isolated view showing only your selected object, making it easier to paint without other objects getting in the way.

The paint panel

When you enter paint mode, a panel appears on the right side of the screen with all your painting tools.

Brush types

You can choose from four brush shapes:

Brush size

Adjust the brush size using the slider (0.1mm to 8mm) or type a specific value.

Smart fill angle

When using the fill brush, the "Smart fill angle" setting controls how aggressive the fill is. A lower angle (like 15°) stops at sharper edges, while a higher angle (like 60°) fills across more of the surface. Set it to 0° to fill only perfectly flat connected regions.

Painting and erasing

• Left-click and drag to paint
• Shift + left-click and drag to erase

The paint overlay shows your work in real-time as you paint.

Color painting

Color painting is for multi-material or multi-extruder setups. You can assign different extruders to different parts of your model to create multi-color prints from a single object.

Select which extruder to paint with from the list - each shows its assigned color. Then paint directly on the model to assign that extruder to those areas.

Support painting

Support painting lets you override the automatic support detection. This is useful when the slicer misses areas that need support, or adds supports where you don't want them.

Enforcer vs blocker

• Enforcer (green) - Forces supports to generate in the painted area, even if the slicer wouldn't normally add them
• Blocker (red) - Prevents supports from generating in the painted area

Use enforcers for tricky overhangs the slicer misses. Use blockers to keep supports away from detailed surfaces or areas where they'd be hard to remove.

Seam painting

Seams are the small lines where each layer starts and ends. By default, the slicer tries to hide them automatically, but sometimes you want more control.

Enforcer vs blocker

• Enforcer (blue) - Tells the slicer to place seams in the painted area
• Blocker (magenta) - Tells the slicer to avoid placing seams in the painted area

A common technique is to paint seam enforcers along a natural edge or corner where the seam will be less visible, and blockers on prominent surfaces you want to keep clean.

Fuzzy skin painting

Fuzzy skin adds a rough, textured surface finish to your print. Instead of applying it to the entire model, you can paint it only on specific areas.

This is great for:

• Adding grip to handles or surfaces you'll touch
• Creating visual contrast between smooth and textured areas
• Hiding layer lines on curved surfaces

Painted areas show up in orange. The fuzzy skin settings in your print profile control the texture intensity.

Clearing paint

To remove all paint of the current type from your model, click the Clear button at the bottom of the paint panel. This only clears the active paint type - for example, if you're in support paint mode, it only clears support paint and leaves your color or seam paint intact.

Exiting paint mode

Click the active paint button again in the toolbar, or press Escape to exit paint mode and return to the normal view. Your paint data is saved with the project and will be included when you slice.

Keyboard shortcuts

Tips for better results

• Start with the fill brush on large flat areas, then switch to sphere or circle for detail work
• Use a smaller brush near edges and details to avoid painting areas you didn't intend
• Rotate your model frequently to check you haven't missed any spots
• Preview your slice to verify the paint is having the expected effect before printing

Updated on: 20/01/2026