Bambu Studio provides a tool for auto-arranging multiple objects on plates. With only one click, many objects can be well arranged.
¶ Parameters and options
There is 1 parameter and 3 options as shown below.
Spacing: the minimum gap between neighboring objects.Auto rotate for arrangement: whether to allow Studio to try multiple angles for better arrangement. A maximum of 4 angles are tried (0, 45, 90, 135 degrees).Allow multiple materials on same plate: whether to allow objects of different materials to be put on the same plate. Note that two materials are regarded asdifferent materialsif they are in different AMS slots, even if they are both the same color PLA.Avoid extrusion calibration region: whether to avoid the extrusion calibration region, which is at the lower part of the heat bed as shown below. If disabled, this region is also utilized for arrangement.
¶ How it works
The underlying algorithm for auto-arranging is libnest2d, a well-known 2D packing package. The process can be shortened as:
- Get the
arrange polygonof all printable objects, which is composed of 1) 2D convex projection polygons, 2) attributes like height, printing temperature, heat bed temperature, etc. A convex projection is the convex hull of the projected polygon onto the heat bed. Non-printable objects are regarded as unpackable and will be put outside of all plates. (in other words, the largest dimensions of the object in any given direction) - Expand the convex polygons by
spacing. (Add the spacing minimum distance to the overall dimensions of the object) - Sort the objects with an ordering function. The ordering function is quite complicated in Bambu Studio. For layered printing (normal slicing), the area is the main concern, meaning that large polygons (objects) are put first. For sequential printing, height is the main concern, meaning lower objects are put first.
- Find a new location for each polygon. libnest2d package gives multiple candidate positions and we find the one with the smallest cost (area used).
- Move objects to their new locations.
¶ When there is a wipe tower
The wipe tower is not movable in auto-arranging to ensure best-wiping effect (can only be manually moved). And to avoid ooze, there are two additional logics:
- When there is a wipe tower on a plate, objects are arranged tightly around the wipe tower but do not exceed the upper bound of the wipe tower. This is to ensure minimum ooze, and always print wipe tower after filament change.
- When doing global arrangement (Arrange All Objects) on multi-color objects, we estimate if a wipe tower is needed. Since we don't know the location of the objects before arranging them, we have to assume that a wipe tower is needed on all plates if it's needed. A wipe tower is needed if:
a. there is a multi-color object;
b. support is enabled and the support interface uses a different filament than the support base;
c.Allow multiple materials on same plateis on, and there are objects using different filaments with the same heat bed temperature (e.g. different color PLA's). - when doing local arrangement (arranging objects on the current plate), we use the actual wipe tower on this plate. So wiping towers on other plates won't affect this plate.
¶ Auto Arranging for by-layer printing
When the print sequence is set to by-layer, the arrange polygon are expanded strictly according to spacing the parameter. Therefore, objects are arranged more tightly near each other.
¶ Auto Arranging for by-object printing
When the print sequence is set to by-object, the arrange polygon are expanded strictly according to max(spacing,extruder_radius). This is to ensure the toolhead won't collide with any already-printed objects (refer to Print-by-object | Bambu Lab Wiki). Therefore, objects are arranged much farther than by-layer printing.
You may notice that the tool head is not symmetric. It's possible to pack objects more tightly if we strictly follow the print order of "bottom to up, then left to right". However, since we allow the free movement of objects and free adjustment of print order, we have to use the maximum radius for collision detection. To keep consistent, the auto-arranging algorithm has to use the same extruder_radius.
¶ How to use
There are 2 modes to do auto-arranging:
- Click the
Arrangebutton in the topmost gizmo, then all objects will be processed. New plates may be added when necessary. Alternatively, use the shortcut keyAto arrange all objects andShift+Ato arrange objects on the selected plate. - Click the arrange icon next to any plate, and then all objects on the plate will be processed. No new plate will be added. If the selected plate can't contain all objects, some will be moved outside.
You may also lock a plate by clicking the lock icon next to it, then the objects on this plate will not be processed by auto arranging.
