juli/OrcaSlicer
1
1
Fork 0
mirror of https://github.com/OrcaSlicer/OrcaSlicer.git synced 2026-10-07 07:41:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

Belt printers: brim laid onto the tilted belt, with a leading apron

Browse Source 
A belt printer slices in a rotated frame, so the belt surface is a tilted
plane rather than the Z=0 bed plane.  Each slicing layer touches the belt
only along a narrow strip at its leading edge - about 0.2mm at 45 degrees -
so a part's first layer is really a first line, with almost no contact patch
to hold it down while the belt drags it forward.  Brim was hard-disabled on
belt printers, leaving no remedy at all.

Generate the brim on the belt plane instead.  The object's belt footprint is
the union over layers of each slice clipped to that layer's contact band; the
brim is offset from it in a "flattened" frame where the shear axis is
stretched by 1/cos(tilt), so ordinary Clipper offsets measure true on-belt
distance.  It is emitted as cross-belt lines, one per layer band, anchored to
a fixed fraction of the band so every line shares a nozzle-to-belt clearance
and therefore comes out the same width; flow is matched to the resulting band
pitch, keeping the sheet uniform and gap-free.

Three new controls, all belt-only:

  * Leading brim length - extends the brim ahead of the part along the belt,
    on every downhill-facing edge of its contact area.  This apron necessarily
    prints BELOW the object's first layer, since layer 0 is the part's leading
    contact, so it needs brim-only bands of its own.
  * Extra brim width - widens the brim sideways across the belt only.
  * Brim type "Leading edge only" - brim at the part's first belt contact and
    nothing after it.  Appended last in BrimType so no existing value shifts;
    degrades to an outer brim off belt printers, with a warning.

The apron bands are lightweight records rather than a Layer subclass, so no
fabricated Layer::id() can leak into initial-layer temperature selection, the
spiral vase probe, cooling or gradual interpolation.  They are generated in
posSupportMaterial because their print_z values must exist before ToolOrdering
is built at psWipeTower, and they are emitted from a short dedicated branch in
process_layer that runs before any layer pointer is dereferenced.

The footprint is closed before offsetting outwards: a belt contact patch is
often a broken-up strip, and the merged offset rings of two islands closer
than 2 x brim_width would otherwise fill the space between them - space that
lies under the part.

Also fixes a pre-existing bug where PrintObject::get_first_layer_bbox()
overwrote a valid bbox with an unassigned one on any belt printer with a brim
configured, because has_brim() was true while make_brim() returned early.

Belt brim is refused alongside the prime tower and spiral vase, and requires
one instance per PrintObject - translating an instance along the belt axis
changes its physical belt-floor Z.  Untilted belt printers are unchanged: they
still get no brim, since the plate brim is emitted out of skirt_brim_groups(),
which _make_skirt() never builds for a belt printer.
This commit is contained in:
harrierpigeon
2026-08-06 01:08:44 -05:00
parent 386364f84b
commit 55b4dca9bc
24 changed files with 1744 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libslic3r/GCode/ToolOrdering.cpp
+43 -2
View File
@@ -468,6 +468,11 @@ ToolOrdering::ToolOrdering(const PrintObject &object, unsigned int first_extrude
zs.emplace_back(layer->print_z);
for (auto layer : object.support_layers())
zs.emplace_back(layer->print_z);
// Belt brim apron bands sit below the object's first layer and have no
// layer of their own, but tools_for_layer() asserts an exact Z match, so
// their print_z must be part of the ordering.
for (const BeltBrimBand &band : object.belt_brim_prologue())
zs.emplace_back(band.print_z);
this->initialize_layers(zs);
}
@@ -512,6 +517,10 @@ ToolOrdering::ToolOrdering(const Print &print, unsigned int first_extruder, bool
zs.emplace_back(layer->print_z);
for (auto layer : object->support_layers())
zs.emplace_back(layer->print_z);
// See the single-object ctor: belt brim apron bands need their own
// ordering entries or tools_for_layer() will assert.
for (const BeltBrimBand &band : object->belt_brim_prologue())
zs.emplace_back(band.print_z);
max_layer_height = std::max(max_layer_height, object->config().layer_height.value);
}
@@ -860,6 +869,30 @@ void ToolOrdering::collect_extruders(const PrintObject &object, const std::vecto
}
}
// Belt brim apron bands own their layers outright: they print below the
// object's first layer, so no object or support layer claims an extruder there
// and process_layer() would bail out at "Nothing to extrude". Claim the
// object's outer wall filament, in the same raw 1-based domain the loops above
// push. Deliberately not layer_tools.has_object, which drives skirt marking
// and wiping overrides.
if (! object.belt_brim_prologue().empty()) {
unsigned int brim_filament = 0;
for (size_t i = 0; i < object.num_printing_regions(); ++ i) {
const unsigned int f = object.printing_region(i).config().outer_wall_filament_id.value;
if (f > 0 && (brim_filament == 0 || f < brim_filament))
brim_filament = f;
}
if (brim_filament == 0)
brim_filament = 1;
for (const BeltBrimBand &band : object.belt_brim_prologue()) {
if (band.fills.empty())
continue;
LayerTools &layer_tools = this->tools_for_layer(band.print_z);
layer_tools.extruders.push_back(brim_filament);
layer_tools.has_belt_brim = true;
}
}
for (auto& layer : m_layer_tools) {
// Sort and remove duplicates
sort_remove_duplicates(layer.extruders);
@@ -902,12 +935,20 @@ void ToolOrdering::fill_wipe_tower_partitions(const PrintConfig &config, coordf_
}
//FIXME this is a hack to get the ball rolling.
// The `print_z < object_bottom_z` clause reads "below the object" as "raft
// gap". On a belt printer that is wrong: the brim apron legitimately prints
// below the object's first layer, and treating those layers as raft would put a
// wipe tower at negative Z. Belt brim and the prime tower are mutually
// exclusive (rejected in Print::validate()), so simply drop the clause there.
const bool belt_no_raft_gap = config.belt_printer.value;
for (LayerTools &lt : m_layer_tools)
lt.has_wipe_tower |= (lt.has_object && (config.timelapse_type == TimelapseType::tlSmooth || lt.wipe_tower_partitions > 0))
|| lt.print_z < object_bottom_z + EPSILON;
|| (! belt_no_raft_gap && lt.print_z < object_bottom_z + EPSILON);
// Test for a raft, insert additional wipe tower layer to fill in the raft separation gap.
for (size_t i = 0; i + 1 < m_layer_tools.size(); ++ i) {
// Skipped on belt printers for the same reason as the clause above: layers
// below the object are brim apron, not raft.
for (size_t i = 0; ! belt_no_raft_gap && i + 1 < m_layer_tools.size(); ++ i) {
const LayerTools &lt = m_layer_tools[i];
const LayerTools &lt_next = m_layer_tools[i + 1];
if (lt.print_z < object_bottom_z + EPSILON && lt_next.print_z >= object_bottom_z + EPSILON) {