Multiple values in printer definition file

hgschmie · December 2, 2025, 2:49am

Bambu Studio stores its standard printer definition files in BambuStudio/system/BBL//machine. Looking at the ‘X1 Carbon 0.4 nozzle.json’ file (which seems to be the base for all the other nozzle sizes, I noticed that it has multiple values for many of the motion ability parameters (e.g. machine_max_acceleration_ or machine_max_speed_).

In the UI, Bambu Studio only shows one value, and it is not even the top one (e.g. for machine_max_speed_x, there are four values: 500, 200, 200, 200 but Bambu Studio only shows 200 for max_speed_x).

Is there more documentation about those values? I looked at Orca Slicer and the Bambu Wiki but did not find much. How are they selected?

Grateful for any pointers.

-h

Bullocks · December 2, 2025, 4:26am

github.com/OrcaSlicer/OrcaSlicer

resources/profiles/BBL/machine/Bambu%20Lab%20A1%200.4%20nozzle.json

bd6cfd6ce


      
              "226x224",
              "256x224",
              "256x256",
              "226x256"
          ],
          "machine_load_filament_time": "25",
          "machine_max_acceleration_extruding": [
              "12000",
              "12000"
          ],
          "machine_max_acceleration_x": [
              "12000",
              "12000"
          ],
          "machine_max_acceleration_y": [
              "12000",
              "12000"
          ],
          "machine_max_acceleration_z": [
              "1500",
              "1500"

github.com/OrcaSlicer/OrcaSlicer

src/libslic3r/Print.cpp

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                  warning_key = "inner_wall_jerk";
             else
                  warning_key = "default_jerk";
          
             warning->opt_key = warning_key;
          }
          
          if (warning_key.empty() && m_default_object_config.default_jerk > 0) {
             std::vector<std::string> jerk_to_check = {"default_jerk",     "outer_wall_jerk",    "inner_wall_jerk", "infill_jerk",
                                                       "top_surface_jerk", "initial_layer_jerk", "travel_jerk"};
             const auto               max_jerk = std::min(m_config.machine_max_jerk_x.values[0], m_config.machine_max_jerk_y.values[0]);
             warning_key.clear();
             if (m_default_object_config.default_jerk > 0)
                  warning_key = check_motion_ability_object_setting(jerk_to_check, max_jerk);
             if (!warning_key.empty()) {
                  warning->string = L(
                      "The jerk setting exceeds the printer's maximum jerk (machine_max_jerk_x/machine_max_jerk_y).\nOrca will "
                      "automatically cap the jerk speed to ensure it doesn't surpass the printer's capabilities.\nYou can adjust the "
                      "maximum jerk setting in your printer's configuration to get higher speeds.");
                  warning->opt_key = warning_key;
             }

When the slicer accesses the settings it seems to often/always? rip the first from the list. .values[0]

I went down the rabbit hole a little but didnt find anything conclusive. Some printer profiles have 1 value, some have 2, and the 3 i checked did not have a good enough git blame to understand why. Whatever the reason, it’s old

mugglesmuggle · December 2, 2025, 10:03am

Thinking again it is the speed modes, silent, etc, just not sure of the order.

But mostly I see only the 1st value (front) being used:

./GCode.cpp:            int(print.config().machine_max_acceleration_x.values.front() + 0.5),
./GCode.cpp:            int(print.config().machine_max_acceleration_y.values.front() + 0.5),
./GCode.cpp:            int(print.config().machine_max_acceleration_z.values.front() + 0.5),
./GCode.cpp:            int(print.config().machine_max_acceleration_e.values.front() + 0.5));
./GCode.cpp:                       ? int(print.config().machine_max_acceleration_extruding.values.front() + 0.5)
./GCode.cpp:                       : int(print.config().machine_max_acceleration_travel.values.front() + 0.5);
./GCode.cpp:            int(print.config().machine_max_acceleration_extruding.values.front() + 0.5),
./GCode.cpp:            int(print.config().machine_max_acceleration_retracting.values.front() + 0.5),