Multicolor and Multi-Filament Printing Guide

This guide explains how to create multicolor prints using Tinkercad and ElegooSlicer with the CANVAS system on the Elegoo Centauri Carbon 2 Combo.

By the end, teachers will understand:

• How multicolor printing works

• The difference between OBJ and STL files

• How to keep colors from Tinkercad

• How to add colors inside ElegooSlicer

• The different paint tools in the slicer

• When to use each method

1. How Multicolor Printing Works

The Centauri Carbon 2 Combo can switch between up to four filament colors using the CANVAS module.

Each color must match:

• A spool position on the printer

• A filament slot in ElegooSlicer

For example:

• Slot 1 = White PLA

• Slot 2 = Red PLA

• Slot 3 = Blue PLA

• Slot 4 = Yellow PLA

The slicer then decides when to switch between those colors during the print.

2. STL vs OBJ: Why File Type Matters

When exporting from Tinkercad, there are two common file types:

• STL
  n- OBJ

STL Files

STL files only save the shape.

They do not save:

• Color

• Different parts

• Material information

If you export an STL, everything will come into ElegooSlicer as one color.

OBJ Files

OBJ files save:

• The shape

• Separate colored parts

• Material information

If you want the colors from Tinkercad to stay with the design, you must export as OBJ.

Teacher Rule

• Use STL for single-color prints

• Use OBJ for multicolor prints

3. Creating a Multicolor Design in Tinkercad

To make a multicolor design:

1. Build the design using separate colored shapes.

2. Change each shape to the color you want.

3. Group the shapes if needed.

4. Make sure each colored area is its own object.

Examples:

• White name tag with red letters

• Baseball bookmark with red stitching

• School logo with multiple colors

Important Tip

The different colored parts must stay as separate pieces in Tinkercad.

If everything becomes one solid shape before exporting, the slicer may not know where one color ends and another begins.

4. Exporting an OBJ File From Tinkercad

1. Click Export in the upper-right corner.

2. Choose “Everything in Design.”

3. Select OBJ.

This exports:

• The model

• The colors

• The separate parts

When imported into ElegooSlicer, the slicer will usually ask if you want to import it as a multicolor object.

Choose Yes.

5. Bringing an OBJ Into ElegooSlicer

1. Open ElegooSlicer.

2. Drag the OBJ file into the slicer.

3. When asked, choose to import it as a multicolor object.

4. Match each color to a filament slot.

For example:

• White areas = Filament 1

• Red areas = Filament 2

If the colors do not match correctly, use the Remap Filaments button.

6. Adding Color Inside ElegooSlicer

Sometimes you may have:

• An STL with no color

• A single-color model that you want to paint

• A design where you want more control than Tinkercad provides

In that case, you can add color directly inside ElegooSlicer.

1. Select the object.

2. Click Color Painting.

3. Choose which filament number you want to paint with.

The screenshot shows the four filament slots at the top:

• 1 = Usually the main color

• 2, 3, and 4 = Accent colors

7. Understanding the Color Painting Tools

ElegooSlicer includes several ways to add color.

Each tool works best in a different situation.

Brush Tool

The round brush lets you paint by hand.

Best for:

• Coloring letters

• Logos

• Small details

• Touching up mistakes

Why teachers use it:

It works like a paintbrush and is the easiest tool to understand.

Fill Tool

The fill tool colors an entire connected surface at once.

Best for:

• Large flat areas

• Entire letters or logos

• Whole sections of a model

Example:

On a bookmark, you could click the baseball stitching once and the whole stitched area turns red.

This is usually faster than brushing every line individually.

Smart Fill or Surface Fill

This tool looks for connected areas and tries to color them automatically.

Best for:

• Models with clear edges between colors

• Logos or signs

Why teachers use it:

It can save time, but sometimes it colors more than expected.

If that happens, undo and use the regular fill or brush tool.

Height Range Tool

The striped tool colors everything at a certain height.

Best for:

• Name tags with raised text

• Logos that sit above a flat background

• Objects where one color is on top of another

Example:

If a name tag has raised letters that are 1 mm tall, you can tell the slicer to color only the top 1 mm red.

This is often one of the easiest ways to color raised text.

Section View Tool

The section view slider lets you cut into the model and see inside.

Best for:

• Looking at hidden features

• Painting inside holes or recessed text

• Checking whether a color goes all the way through

Why teachers use it:

Without section view, it can be hard to tell if the correct parts are colored.

8. Vertical and Horizontal Painting

The screenshot also shows options for:

• Vertical

• Horizontal

These control the direction of the painting.

Vertical

Vertical painting colors straight up and down.

Best for:

• Side text

• Logos on the side of an object

• Vertical stripes

Horizontal

Horizontal painting colors layer by layer.

Best for:

• Top surfaces

• Raised text

• Objects with one color on top of another

Example:

For a bookmark with a baseball on the surface, Horizontal is usually the easiest option.

9. Pen Size

Pen Size changes how large the paintbrush is.

• Small pen = More detail

• Large pen = Faster painting

Best practice:

• Start large for big areas

• Switch smaller for details

10. Remap Filaments

The Remap Filaments button lets you switch which color is assigned to each spool.

Example:

If the slicer thinks the baseball stitching should be blue but you loaded red in slot 2, use Remap Filaments to fix it.

This is much easier than repainting the entire object.

11. Prime Towers and Why They Matter

Whenever the printer changes colors, it needs to clean out the old filament.

The slicer creates a Prime Tower beside the object.

The prime tower:

• Uses extra filament

• Makes sure colors stay clean

• Helps prevent one color from mixing into another

Without a prime tower, you may see:

• Pink where red should be white

• Blue streaks in yellow

• Mixed colors at the start of each section

12. Ways to Reduce Wasted Filament

Multicolor prints use more filament because of the color changes.

To reduce waste:

• Use fewer color changes

• Keep colors on the same layer together

• Use Flush Into Infill when possible

• Avoid tiny color details unless necessary

Teacher Tip:

A design with two colors is much faster and wastes less filament than a design with four colors.

For a first project, try:

• White background

• One accent color

13. Best Beginner Multicolor Projects

Good first projects include:

• Name tag with colored text

• Bookmark with a simple logo

• School mascot keychain

• Sports logo with two colors

These are easier because:

• The color areas are large

• The print stays flat

• There are only one or two color changes

Avoid:

• Tiny detailed logos

• Four-color prints

• Miniatures with many color changes

14. Common Problems and Fixes

15. Best Workflow for Teachers

For most classroom projects:

1. Design in Tinkercad

2. Use different colors on different shapes

3. Export as OBJ

4. Import into ElegooSlicer

5. Match the colors to filament slots

6. Adjust with the paint tools if needed

7. Slice and print

If students already built a project as an STL, you can still add color afterward in ElegooSlicer using the paint tools.

The easiest path is usually:

• Use Tinkercad colors when possible

• Use the slicer paint tools for small changes and touch-ups