How to import ground mesh made by 3dmax into UE4 with accurate collision

I build a terrain scence in 3dmax. But when i import the terrain model into UE4 ,I always can’t get accurate collision .That is to say,when I was in the play mode,the charactor will float in the air.what can i do now? You know the scence is a somewhat large one.

Generate a height map from Max and import it using the landscape tool.

Thank you Bino for your instruction,but in this case ,the terrain is generated by the contour line of the terrain .I wanna simulate a existing terrain landscape in a very percision way.So I afraid that height map will not contain so much accurate
information of the terrain surface. Then what can i do about the collision.

I see what you mean.

Two potential options.

If you want accurate but expensive colission. In your static mesh settings set your collision to “use complex as simple”.