"smooth terrain" is correct and can be used in written English.
It refers to a surface or landform that is even and free of roughness or obstacles. Example: The hikers were relieved to finally reach the smooth terrain at the base of the mountain, after struggling through rugged terrain for hours.
Eagle had touched down in the Sea of Tranquility, an area selected for its level and smooth terrain.
But there is much evidence of wind erosion — the crater has widened to about 2,500 feet, forming indentations and promontories along the rim, and ejected rocks outside have been planed down, leaving smooth terrain.
Nine years after New Horizons launched, the flyby past Pluto quickly delivered stunning results: the first clear image of the distant planet since its discovery, a world capped by icy poles, spotted with dark patches and stamped by a huge, heart-shaped swath of smooth terrain.
The boundary layer is 60 m high for smooth terrain.
An inchworm locomotion device is presented that can walk on smooth terrain.
Rambling around the world is a bouncy and playful process, with smooth terrain that doesn't really scream voxel in any way.
And that error is larger than any of the apparently smooth terrains in the J zone.
And that error is larger than any of the apparently smooth terrains on the reachable parts of the comet.
Therefore, we conduct the experiments on smooth terrains and down a slope to evaluate the performance of the roller-skating motion, including gait stability and velocity.
Its surface was basically rough and covered with boulders, but smooth terrains such as MUSES-C Regio also existed where the first and second touchdown operations were conducted for sample collection (see Fig. 1).
In order to improve the speed performance of the spherical robot on a slope or comparatively smooth terrains, we propose a new roller-skating mode for the robot by equipping a passive wheel on each leg to implement the roller-skating motion in this paper.
