Tips · · By the usi3d team
How to save filament in 3D printing: infill, walls, supports and vase mode, with real numbers
The biggest filament saving comes from matching infill to what the part is for: on a 50 mm cube, dropping from 25 % to 10 % takes it from about 50 g to about 29 g. Next come tree supports, vase mode for hollow parts, printing slightly smaller and flushing into the part when you use several colours. A thicker layer height saves time, not plastic.
Key points
- On a part with little infill, most of the plastic sits in the walls, top layers and bottom layers.
- For parts that are only looked at, 8-10 % lightning infill holds up the top layers with very little plastic; for load-bearing parts, add walls before infill.
- Vase mode prints a single spiral wall: an 80 × 150 mm vase drops from about 90-100 g to about 25 g.
- At 90 % scale you save between 19 and 27 % of the filament; at 80 %, close to half.
- Every colour change purges filament: with two colours over 300 layers, the purge can weigh more than the figurine.
Where a part's filament goes
A printed part has a skin (walls, top and bottom layers) and an interior filled with infill. With the settings most slicers start from (two walls, 15 % infill and 0.2 mm layers), the skin often weighs as much as the infill or more. That is why cutting infill from 15 % to 5 % does not cut the weight to a third: the skin is still there.
Take a 50 mm cube in PLA (1.24 g/cm³), with 0.42 mm lines and four 0.2 mm layers top and bottom. It is a simplified calculation and your slicer will give slightly different figures, but the proportions hold.
| Setting | Approximate weight | Comment |
|---|---|---|
| Solid (100 %) | 155 g | Only worth it for very small parts or ones you will machine |
| 2 walls, 25 % infill | 50 g | Strong; for parts that do real work |
| 2 walls, 15 % infill | 36 g | The standard profile in many slicers |
| 3 walls, 15 % infill | 40 g | Stronger than going to 25 % and 10 g lighter |
| 2 walls, 10 % infill | 29 g | Plenty for decorative parts |
With PLA at €20 a kilo, each gram costs 2 cents. Saving 20 g on a part is 40 cents, and on a batch of ten parts, €4. For the full sum including electricity and wear, see how much 3D printing costs.
Which infill to use for each kind of part
| Use | Infill | Walls | Why |
|---|---|---|---|
| Decorative (a figurine, an ornament) | 10 % lightning | 2 | Lightning infill only grows under the top layers to hold them up |
| Size or fit test | 8 % lightning | 2 | It will be thrown away: just enough to stop the top sagging |
| Functional (a box, a clip) | 15 % adaptive cubic | 2 or 3 | Dense next to the walls and sparse in the middle |
| Load-bearing or outdoors | 25 % gyroid | 4 | Strength lies mostly in the walls |
Lightning infill is available in Bambu Studio, OrcaSlicer, PrusaSlicer and Cura. It saves a lot on figurines with rounded heads and little on parts with a large flat top, which needs support across its whole surface. Prusa explains it well in its guide to infill patterns.
Walls: more strength per gram
On the cube above, going from 2 to 3 walls costs about 4 g; raising infill from 15 % to 25 % costs about 14 g. The extra wall loop adds more strength than that infill, because bending loads and knocks are carried mostly by the skin. If a functional part keeps snapping, try one more wall before more infill.
Supports: tree style and good orientation
Normal supports raise straight columns under every overhang; tree supports (organic in PrusaSlicer) grow from a few points and branch out, and on figurines they usually use far less plastic. Before that, rotate the part: resting it on the face that leaves the fewest overhangs can remove supports in one go. And paint support blockers where an overhang is short or decorative, because the slicer adds supports by slope, not by need. If supports give you trouble, see the guide to supports that fail or will not come off.
Vase mode: one spiral wall
Vase mode (spiral vase) prints a single wall that climbs in a spiral, with no top and no infill; only the bottom is printed normally. A vase 80 mm across and 150 mm tall, with a 0.4 mm wall and a 1 mm base, weighs about 25 g. The same vase modelled with 2 mm walls and printed normally comes to about 90-100 g.
There are two conditions: the part comes out hollow and open at the top, and at any height it can only have one outline. It suits vases, planters and lampshades, not a figurine. Bambu Lab covers it on its spiral vase page.
Scale, layer height and other settings
- Print slightly smaller. Infill drops with the cube of the scale and walls with its square: at 90 % you save between 19 and 27 %, and at 80 % the volume halves (0.8³ = 0.51). Only if size does not matter; never on parts that fit together.
- Layer height saves time, not plastic. Going from 0.2 to 0.28 mm prints the same volume in fewer layers. Worth it for a test print; for a figurine, adaptive layer height is the better choice.
- Brims and rafts only when needed. A raft under a large part can add several grams. If the first layer grips well, you do not need it; if not, fix the cause with the guide to first layer not sticking.
- Use up spool ends. The last few metres are fine for size tests and small single-colour parts.
Several colours: flush into the part
With an AMS or an MMU, every colour change pushes out filament until the new one runs clean. usi3d works on about 435 mm³ per change on a Bambu Lab printer with an AMS, just over half a gram of PLA. A 60 mm figurine with two colours on every 0.2 mm layer adds up to about 300 changes and about 160 g of purge. Flushing into the object's infill or supports puts some of that plastic to use; with light colours, go up to 3 walls so it does not show through. We cover it in depth in how to paint a model in several colours.
The biggest saving: a print that does not fail
An 8-hour print that comes loose at hour 6 wastes more filament than all the settings above put together. Check bed adhesion, damp filament and warping before starting long jobs: there are guides on damp filament and drying and on corners lifting.
How to work out the saving on your part with usi3d
Open your model
Go to Save filament with AI and open an STL, 3MF, GLB or OBJ, or one of the samples: a bull, a vase, a cable winder and a gear. The calculation runs in your browser and uses no credits.
Say what it is for
Choose the use (decorative, vase or lampshade, test print, functional, load-bearing or outdoors), your printer, the material and what a kilo costs you.
Compare the tricks
You see the grams with the standard profile and with each trick that suits that part (infill, walls, supports, orientation, vase mode, scale, flushing), with its effect on strength and time and the sources behind each one.
Or ask the AI
Write what the part is for, for example “a shelf bracket for 3 kg”, and press “Save filament with AI”. It tells you which tricks to turn on and why, with the grams worked out by the page. It is free with your account, with a daily limit of questions.
Download it for your slicer
Bambu Studio, OrcaSlicer and the slicers derived from it, PrusaSlicer and SuperSlicer get a 3MF with the part in its orientation and the settings on the object itself. Cura gets the per-model settings it supports; other slicers get the STL and the settings written out. Since 3 November 2026, the download comes with the Pro, Max or Business plan.
We checked the calculation by slicing five shapes and four sample models with 62 profiles in Bambu Studio: the part comes within 1.3 % of the slicer on average (6 % in the worst case), tree supports within ±15 % and normal ones within ±35 %. It is an estimate: always check the slice preview. For the full cost of the part, use the 3D print cost calculator.
Frequently asked questions
What infill percentage is enough?
For decorative parts, 8-10 % lightning infill; for functional parts, around 15 %; for load-bearing parts, 25 % plus extra walls.
Which infill uses the least filament?
Lightning infill, which only grows under the top layers to hold them up. It suits parts that are only looked at; it adds no strength.
How much filament does vase mode save?
A lot on hollow parts: an 80 × 150 mm vase drops from about 90-100 g to about 25 g. In exchange, the part has a single wall and is open at the top.
Does a thicker layer height save filament?
Hardly at all: the part's volume is the same. What it saves is time, because it prints fewer layers.
Should I add walls or infill to make a part stronger?
Walls. One extra wall loop gives more strength than raising infill and usually uses less plastic.
How do I reduce purge waste when printing in several colours?
Use fewer colours, keep small colour details within a few heights and turn on flushing into the object's infill or supports.