Robot simulators provide an easy way for evaluation of new concepts and algorithms in a simulated physical environment reducing development time and cost. Therefore it is convenient to have a tool that quickly creates a 3D landscape from an arbitrary 2D image or 2D laser range finder data. This paper presents a new tool that automatically constructs such landscapes for Gazebo simulator. The tool converts a grayscale image into a 3D Collada format model, which could be directly imported into Gazebo. We run three different simultaneous localization and mapping (SLAM) algorithms within three varying complexity environments that were constructed with our tool. A real-time factor (RTF) was used as an efficiency benchmark. Successfully completed SLAM missions with acceptable RTF levels demonstrated the efficiency of the tool. The source code is available for free academic use.