- Implemented vtk base for viewing

drawing_modules/draw_widget2d.py

@@ -635,8 +635,10 @@ class SketchWidget(QWidget):
         return self.width() / self.height() * (1.0 / abs(self.zoom))
 
     def clear_sketch(self):
-        self.points = []
-        self.update()
+        self.slv_points_main = []
+        self.slv_lines_main = []
+        self.reset_buffers()
+        self.solv = SolverSystem()
 
 
 # Example usage