I'm trying to import a stl file manually via python. My code below is pretty straight forward, but I'm struggling with the following line. I'm not sure about the syntax and format of the arguments:

bpy.ops.import_mesh.stl(filepath=???, files=???)

The current state of my operator:

import bpy

class FILE_OT_import_stl(bpy.types.Operator):

    bl_idname = "file.import_model_stl"
    bl_label = "Import Model STL"
    bl_options = {'REGISTER', 'UNDO'} # Must have REGISTER!   

    def execute(self, context):
        #my_filepath = 'K:/PQJ/Mold Generator/Blender test/'
        #filepath = '//898L-OutputModel-SLA[]_09'
        bpy.ops.import_mesh.stl(filepath=my_filepath, files=all_files)
        return {'FINISHED'}

class FILE_PANEL_PT_import_export(bpy.types.Panel):
    bl_label = "Import/Export"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    # bl_context = "object" # object vs edit mode

    def draw(self, context):
        layout = self.layout
        layout.prop(context.scene, "import_path")
        row = layout.row()                

classes = (

def register():
    for cls in classes:
        bpy.types.Scene.import_path = bpy.props.StringProperty(name='Import path', subtype='FILE_PATH')

def unregister():
    del bpy.types.Scene.import_path
    for cls in classes:

if __name__ == "__main__":

Q: How to import a certain STL file using the file browser (and add a custom material)?

  • $\begingroup$ Do bpy.ops.import_mesh.stl(filepath="your/path/here.stl"). $\endgroup$ – scurest Nov 13 '20 at 9:59
  • $\begingroup$ I tried that but it didn't work. Also I am trying not to hard code the path but get it from my custom prop. $\endgroup$ – DrDress Nov 13 '20 at 10:09
  • 1
    $\begingroup$ Depending on the situation you can just call bpy.ops.import_mesh.stl('INVOKE_DEFAULT') or use layout.operator("import_mesh.stl", text="Import STL", icon='FILE_NEW') in your draw method if you want to import 1 file. Have a look into the Operator File Import template (magic is done by its ImportHelper class). Related: How to use the File Browser's (with ImportHelper) execute function?, batch import example: How to batch import Wavefront OBJ files?. Do you'd like to import 1 or a few files? $\endgroup$ – brockmann Nov 13 '20 at 12:06
  • $\begingroup$ It's just 1 file and it needs to be selected by mouse click. After import I need to do a few things to the object - otherwise I could just use the import in the menu $\endgroup$ – DrDress Nov 13 '20 at 12:07
  • $\begingroup$ It is selected anyway... $\endgroup$ – brockmann Nov 13 '20 at 12:07

You can just add the built-in operator import_mesh.stl to your draw method of your panel which will open up the File Browser as usual and allows the user to select one .stl file:

enter image description here

import bpy

class OBJECT_PT_CustomPanel(bpy.types.Panel):
    bl_label = "My Panel"
    bl_idname = "OBJECT_PT_custom_panel"
    bl_space_type = "VIEW_3D"   
    bl_region_type = "UI"
    bl_category = "Tools"
    bl_context = "objectmode"

    def draw(self, context):
        layout = self.layout
        #layout.operator_context = 'INVOKE_DEFAULT' #'INVOKE_AREA'
        layout.operator("import_mesh.stl", text="New", icon='FILE_NEW')

def register():

def unregister():

if __name__ == "__main__":

Related: How to call a confirmation dialog box?

In case you want to import and modify the .stl object for whatever reason, have a look into the Operator File Import template (operator_file_import.py) that comes with Blender.

enter image description here

Demo operator based on the template, allows to import the file, print the object reference and assigns a new material to the incoming object in one go:

# ImportHelper is a helper class, defines filename and
# invoke() function which calls the file selector.
from bpy_extras.io_utils import ImportHelper
from bpy.types import Operator

class ImportSomeData(Operator, ImportHelper):
    """This appears in the tooltip of the operator and in the generated docs"""
    bl_idname = "import_test.some_data"
    bl_label = "Import Some Stl File"
    bl_options = {'REGISTER', 'UNDO'}
    # ImportHelper mixin class uses this
    filename_ext = ".stl"
    filter_glob: bpy.props.StringProperty(
    def execute(self, context):
        if self.filepath:
            # Print the imported object reference
            print ("Imported object:", context.object)
            # Create a material
            mat = bpy.data.materials.new(name="STLMaterial")
            # Append the material to the last slot

        return {'FINISHED'}

Further reading:

  • $\begingroup$ Yeah. The 'INVOKE_DEFAULT' works like a charm. But I need to change the name of the object right after import (and maybe a few other things). This only imports (like in the menu) $\endgroup$ – DrDress Nov 13 '20 at 12:42
  • $\begingroup$ I have seen the template and it just says: "bpy.ops.import_mesh.stl(filepath=self.filepath)". I can't find where "self.filepath" is set. $\endgroup$ – DrDress Nov 13 '20 at 12:47
  • $\begingroup$ Comes from the ImportHelper class, see my demo code. $\endgroup$ – brockmann Feb 22 at 10:06

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