How to Paint Multi-Colour Models in Bambu Studio for the AMS

Getting a clean two-tone or full-colour print out of an AMS comes down to two things working together: telling Bambu Studio exactly which slot paints which region, and tuning how much filament gets purged on every colour swap. Learn to paint multi-colour models in Bambu Studio properly and you turn a printer that swaps filament into one that prints a finished, sharp-edged colour design straight off the plate.

Quick Answer

Use the Colour Painting tool to assign an AMS slot to each region of the model, then adjust Purging Volumes in Filament Settings so each colour change flushes enough old plastic to avoid bleed. Dark-to-light swaps need the most purge (roughly 180 to 240 mm3); light-to-dark need far less (around 100 to 120 mm3). Tick "Flush into infill" or "Flush into object" to dump waste inside the print instead of the purge tower.

Step 1: Load and slot your filaments

Open the AMS panel in Bambu Studio and confirm each spool is set to the correct filament type and colour. The slot colour you pick here is what the painting tool shows you, so set it accurately before you start. If you are running an AMS with four colours, you have four slots to paint with on a single plate. The slicer maps slot one through four to the painting palette in the same order, so a quick glance at the AMS panel tells you which colour you are about to apply.

Step 2: Paint the model region by region

Select the object and open the Colour Painting tool from the left toolbar. Pick the first AMS slot from the palette, then choose a brush. The fill bucket flood-fills a connected surface, the circle brush paints freehand with an adjustable radius, and the triangle or height tools split the model along a flat plane, which is ideal for a logo band or a layer-height colour change. Rotate the model as you go and check every face, because unpainted regions default back to the first slot and that is the most common cause of a stray colour appearing where you did not expect it.

Step 3: Understand what flush volume actually does

Every time the printer switches colour, it has to push the old filament fully out of the hotpath before the new colour comes through clean. That purged plastic is your flush volume. Set it too low and the previous colour bleeds into the new one, leaving a muddy edge. Set it too high and you waste filament and add minutes to every swap. The asymmetry matters: a pale yellow contaminated by even a trace of black looks filthy, so dark-to-light transitions need a heavy purge, while a dark colour hides a little leftover light filament easily and needs much less.

Step 4: Set and trim flush volumes

Go to Filament Settings and open the Purging Volumes matrix. Bambu Studio fills in conservative defaults automatically, and those defaults are a safe starting point. To save filament, lower the values for transitions where the destination colour is dark, and keep them high where the destination is light. Slice, open the preview, and inspect the colour boundaries layer by layer. If you see bleed, raise that specific transition; if the edges are crisp, you have room to trim further. Tuning one transition at a time and re-slicing is the reliable way to find the floor.

Step 5: Cut waste with infill flushing

The purge tower beside your print is pure waste. Enable "Flush into infill" so the slicer pushes purged filament into the model's own infill, or "Flush into object" to route it into a sacrificial body. On a print with dense infill and many colour changes this can reclaim a large share of what the tower would otherwise throw away. For the storage tubs, side cutters, nozzle picks and spare PTFE that make a colour-printing setup run smoothly, the printer accessories and consumables on the best sellers list are worth keeping stocked.

Frequently Asked Questions

Why is my second colour bleeding into the first?

Your flush volume for that transition is too low. The printer has not purged enough of the previous filament before laying down the new colour. Raise the purge value for that specific colour pair in the Purging Volumes matrix and re-slice to check.

Does flushing into infill weaken the print?

Not meaningfully for most parts. The purged filament becomes part of the internal infill, which is hidden and not load-bearing on typical decorative or hobby prints. For functional parts under stress, flush into a separate object instead so the structural infill stays a single colour.

How many colours can I print on one plate?

As many as you have AMS slots loaded, typically four per AMS unit. Painting more colours than you have slots is not possible on a single plate without manual filament swaps mid-print.

Can I save my flush volume settings?

Yes. Once you have dialled in purge values that work for a given set of filaments, save them as a custom filament or process preset so you do not have to retune for the next print using the same spools.