I am new to Python. I am facing following error: NameError: name 'ObjFile' is not defined

Question

from objloader import ObjFile


class Renderer(Widget):
    def __init__(self, **kwargs):
        self.canvas = RenderContext(compute_normal_mat=True)
        self.canvas.shader.source = resource_find('simple.glsl')
        self.scene = ObjFile(resource_find("monkey.obj"))
        super(Renderer, self).__init__(**kwargs)
        with self.canvas:
            self.cb = Callback(self.setup_gl_context)
            PushMatrix()
            self.setup_scene()
            PopMatrix()
            self.cb = Callback(self.reset_gl_context)
        Clock.schedule_interval(self.update_glsl, 1 / 60.)

    def setup_gl_context(self, *args):
        glEnable(GL_DEPTH_TEST)

    def reset_gl_context(self, *args):
        glDisable(GL_DEPTH_TEST)

    def update_glsl(self, delta):
        asp = self.width / float(self.height)
        proj = Matrix().view_clip(-asp, asp, -1, 1, 1, 100, 1)
        self.canvas['projection_mat'] = proj
        self.canvas['diffuse_light'] = (1.0, 1.0, 0.8)
        self.canvas['ambient_light'] = (0.1, 0.1, 0.1)
        self.rot.angle += delta * 100

    def setup_scene(self):
        Color(1, 1, 1, 1)
        PushMatrix()
        Translate(0, 0, -3)
        self.rot = Rotate(1, 0, 1, 0)
        m = list(self.scene.objects.values())[0]
        UpdateNormalMatrix()
        self.mesh = Mesh(
            vertices=m.vertices,
            indices=m.indices,
            fmt=m.vertex_format,
            mode='triangles',
        )
        PopMatrix()


class RendererApp(App):
    def build(self):
        return Renderer()


if __name__ == "__main__":
    RendererApp().run()

Answer 1

Your code is copied from the kivy 3dRendereing example, but you haven't copied the entire example. That code requires the objloader.py file (as well as monkey.obj and simple.glsl). Copy all those files into the same folder, then the code should work.