This paper presents the design and implementation of a collision management module. This module is part of a specific graphic engine that manages large size terrain data. This engine has been used for example in a Basque Country terrain demo with a database up to 2.5Gb and texture resolution of 1024x1024 (3mts/pixel). As data textures are increasing resolution it seems convenient to allow near-terrain navigations. This behavior makes more complex the collision problem while navigating a large database. The main purpose of this project is the integration of a new collision module without any remarkable decrease in the performance of the engine. This work comprises the following research topics: preprocessed collision data structure definition, collision data management algorithm in execution time, collision detection algorithms and collision response algorithm. It has provided more flexibility in the interaction of the engine with the user, and more realism overflying terrains.